I think you are the first person on earth (at least on RUclips) taking all the suggestions seriously and try those out. But trying no harm as long as you have all the options with you. I really appreciate your sincerity in trying things and for respecting your subscribers!
Thank you, Nazeer, for saying so. I'm still learning. And a lot of good ideas and info comes in the comments section. Thank you for the encouraging words and thanks for watching.
Thanks for the encouragement Craig. RUclips is a knowledge community and the video creators don’t always have all the answers. Lots of great feedback and ideas in the comments. Thanks for watching.
i love the fact that you muted the noise from the grinder. Nobody else seems to be able to figure that out. It is so much better to not have to listen to the power tools. Major thumbs up. Thank you.
One thing you might want to try on the next stove to prevent cracking is waiting longer before firing it. Normal concrete usually takes 28 days to achieve the majority of its strength. Using perlite it may take even longer.
I don't know what I would do without you-tube. Having you-tube is the best for interesting issues, it's a marvelous time to be alive. I'am truly learning a lot. And the thought of a little stove to cook with when you are away from home out camping or just taking a nature trip, I'am so grateful for the many people who are investing their ideas on you-tube. THANK YOU
I like the steel band that's now holding the concrete together so the rocket stove can properly burn its fuel. The fact that you are using that band to hold up the feed ramp is a nice design detail. Keep cooking Tom!
Thanks Greg. I think I may add another band. The method I used to connect the two ends of the band allows for some expansion, which will allow the concrete to breathe a little. Thanks for the feedback.
To me, it seems your feeder is feeding the wood more to the edge of the stove instead of the middle of the stove where your fire is. Seems like the fuel feed hole should be a little higher and the upper and lower edge should have a 45 degree angle so that the wood feeds into the center of the fire chamber better.
I agree. I saw what you are seeing. I had a suggestion to angle the roof of the firebox up. That would allow the ramp to be higher and a steeper angle. Both of those things would help get the fuel into the middle of the firebox versus the edge. Thanks for all the feedback.
I wonder if you’ve considered aligning your rocket stoves with the prevailing winds. I learned that from a Thai woman who is accustomed to building her own outdoor earthen cooker for her big wok. She says it’s common practice in Thailand to point the air gap (and fuel gap) toward the incoming wind. It makes sense to me.
What rail line do you live next to? One suggestion when making a new core, don't bother with the pvc insert. Just use a heavier grade cardboard tube like the ones used for carpet rolls. Once the core is set, you can just burn the cardboard out.
This is a good design and to make it seem easy to build which means it must be easy, definitely going to be an addition to my pizza oven area which is also going to be your design
Methinks the grate on right angles to the feed tube is stopping the fuel from making it right into the chamber, causing burning at the front and the j tube to be quite ineffective. It's also likely to be helping the existing crack get worse as there's heat right under that part of the wall.
I found your youtube site today and I find it to be super interesting with fun projects to do with my grandson. I've been following the videos on your rocket stove builds, you have come a long way with improvements. I was sad to see that you got a crack in your last project stove and I had a feeling that would happen without any internal wire reinforcements. The metal band is the best solution for that, but you really need to make it relatively tight, really tighten down on it and add a second band down lower near the fire box opening or at least half way down. The feed ramp, like you said is a great addition, but not necessary, but when I make one with my grandson, I will add one, as it serves as a great place to stag some fuel and feed it in. Again, so happy I found your site, I also love the bread oven project, another one for me and my grandson.
This is the answer to all your problems. First of all, when mixing all the ingredients use as little water as possible, such as just enough, because to much water will weaken the cement. Also, there is to much friction for dry wood to slide down a piece of rough bare steel, so simply lay some bathroom tiles on it for a non friction slide, and you will find that you can get away with much less of an angle if you want because the wood will slide very easily. Also, and a major point here, the whole slide itself should be higher, to the point that all the wood wants to head for the rear of the riser. This means that the side opening needs to be higher and not down to the bottom of the riser as you have it now. Don't worry, as the wood burns, it will fill the entire bottom, and will burn extremely well. Also, those that commented about the grate are right, as the grate bars need to run in the direction that the wood wants to slide down, otherwise the wood hits them and stops. Another major point, to prevent cracking, not only wait a month for it to dry, but the first six fires should be very small. This is very MAJOR. Light a small fire using only a few pieces of small wood, and let it burn out and then wait for the stove to cool completely, then do the same thing five more times. After that make a medium size fire and let it cool. If you do all these very simple things you will be ready to do some serious cooking.
If you want to do long fires that don’t need to be tended you would definitely benefit from a feed system. However using long sticks like that won’t funnel in easily. Make a bunch of charcoal from those dried scraps and use that initial height of the ramp. The smaller charcoal pieces will fall down into it without being forced. P.S. make a tray to catch the ash and collect it to use in conjunction with the perlite in your next concrete mixture.
So using the ramp, I would Remove the grate to let sticks fall in deeper inside to the ground and still keep the unburned fuel segregated. Continue to use the underneath bricks elevating ramp or grate for the air path. Like you did, using the ramp to separate the unburned fuel while resting on the bricks should suspend the wood over the air-gap without the grate sufficiently, you think? Ramp OR grate, maybe not both together? Bricks underneath and dug out for the airchannel, both ways, are the key factors I noticed.
The rails of the gate need to run with the flow of the wood not against it percents the wood from feeding if the grate was cut so the wood could slide the ramp could be any angle and not impede the feed
When you build your next stove. An idea for the reenforcement: 1. Run the rebar (pot pegs) all the way through the form and use a round hoop at the top and bottom of the form to hold in place.
Perhaps nuts and bolts might work better for the pot holders since you can fix the depth with the nut. Im inspired to make my own rocket stove. Do you think I could use clay harvested from the lake instead of cement?
Might not hurt to extend the riser about another foot or two by making another tube from the mix and putting it on top of what's there now. Also make the hole taper slightly to reflect some of the heat back downwards and help increase the updraft speed.
I'm sure someone has pointed this out already, or you have figured it out yourself. The main problem with your feed ramp is not the ramp, it's the direction of your grate. The wood cant slide in as it burns down, because it's catching on the grate underneath the feed ramp. Rotate your ramp 90 degrees and your feed ramp will work properly. Great video, thank you for the effort and instruction.
Hi Avatar. Yes, you are correct on both accounts. :-) The grate is the wrong way, and a lot of people have noticed that as well. I think I'll just eliminate the grate when I use the feed ramp. And only use the grate when it goes in flat. Thanks for the feedback.
Sewer hose clamps hooked end to end make a very easy strap. There is nothing wrong with a crack in your stove as long as you have straps to hold it together. For that matter you could cast your stove in parts and clamp the parts together. It would be an interesting experiment to clamp your C Channel vertically to the face of your stove so that sticks slide down into the mouth of the opening creating your J channel. Another idea to give yourself height, cast two buckets. The lower one would be the burn chamber and the upper one would be the chimney. Lower chamber would be made like a normal rocket stove. Although you can make the burn chamber larger...perhaps 6 or 8 inch...and with the standard side feeding channel. Come to think of it, if the top piece is the chimney/cook top, then the bottom piece could be cast in a rectangular box to allow for creativity...even a J channel.
Hey GreenShortz, A true J tube actually contains the the feed section on the short side of the > J where the wood will stand straight up, and slowly drop as it burns. The burn area is along the bottom horizontal section of the J , and the fire is naturally drawn sideways from the burning wood by the draft from the chimney/heat riser. The heat riser is along the long side of the J < . I would recommend fire brick for the feed and burn sections, and then a section of steel well pipe for the heat riser, then using a larger diameter of HVAC round duct, you can create an area to fill with vermiculite to insulate the steel pipe with makes is like a catalytic converter. then put your cement mixture around the outside of the duct if you are using outdoors for stove. If wanting to convert to a rocket heater, I would not use cement, it would not stand up to sustained high temp burning.
I haven't read the comments to find out if someone else may have made this suggestion but your grate to allow for air flow grills should run parallel with feed instead of perpendicular which causes the fuel to hang up at the mouth.
I was wondering....when you do the initial build and put your milk bottle in, could you angle it a bit to help with the slope of the J ramp thing? Would that help it instead of doing that part at a right angle?
@GreenShortz DIY A good suggestion I’d say to help your chute feed the main chamber is to make your grill runs, run vertical to your chute as apposed to laterally (parallel) and gravity will be your best friend. Keep up the great work ✌🏽.
Look at mark Thomas 6” rocket stove. He has a 4” also. Adapt his feed to the front of your cement stove. Should work very well. Great vids. Can’t wait to make on of these.
I'm loving the stove. I'm a little late to the party, but I wonder if your grate is actually hindering the autofeed.. Maybe if you had it where the grating was parallel to the feed ramp instead of perpendicular, if may autofeed a little better. My thinking is that it is catching the leading edge of the wood and stopping it.
You're never late to a rocket stove party! :-) I do think you are right. I think the grid works better without a ramp. And the ramp should work better without the grate, or at least switching the direction of the grid to the same direction as the feed. Thanks for the feedback. Thanks for watching.
With that grill running across the feeder, it will always catch what you trying to feed in. If the grill was running inline with the feeder the wood should slide in better.
Hi Glen. I had a similar thought. I’ve still got the other 2/3rds of that grill. I’ll have to make that mod when I redo this. Thanks for the suggestion.
Can you do a video showing how to install a copper pipe heat exchanger to heat hot water by natural heat siphoning process ? How much time and fuel is needed to heat 40 gallons ?
If you block the airflow from below the grate and just use that as a clean out port, you wont have to worry about the fire rising up the feed tube because the air draw will stop that from happening. This is also why a vertical feed tube for gravity feed of the sticks works without the feed tube becoming a chimney.
to add another element to your stove use a much larger bucket to form a new outside of your stove. to create a void between the 2 buckets for you to fill with pearlite. that will allow for a super heated flue. extend the floor of your burn chamber and make a ceiling out of your firebrick, then add your ramp at the very end of the new floor of your burn chamber. Oh I just remembered something: the grate is not a good idea you needed a piece of plate steel instead. hot air on top, cold air underneath creates a vortex in flue if I remember correctly.
Your grate needs to have wide slats, flat and smooth, parallel to the fuel/sticks. The grate also could have a slant to it half that of the feed ramp for another way to help product move into the firebox. I like the palm frond stems, slick on their exterior, stiff. But not much mass, so they don’t move in well. Placing a weighted sled behind them would keep them against the back of the firebox, and as they are consumed and crumple, the smooth grate may allow them to advance....
The Grate impedes the use of the ramp. Maybe a perforated sheet metal interior grate? The ramp does allow for longer fuel to be added and manually pushed in as needed. Short of burning pellets of a uniform size and a shaker to help feed. I can not see where the ramp is a plus.
Excellent work, dude! One thing that might make the self feeding easier is to make the gate run parallel to the direction of wood travel. Right now, the wood has to jump over obstacles to slide in.
Good suggestions Roy. Thanks for the feedback. I’ll be making several more of these rocket stoves to incorporate all the good ideas. Thanks for sharing.
What did you do with the rest of the grill grate? Cut it so the wood feeds parallel with the grate instead of perpendicular. You might have to use two sections together to get the length you want
Hi Stephen. I still have the other piece. I think in the end I will use the grate without the feed ramp and the feed ramp without the grate. But, your observation is correct, the perpendicular bars, stopped the wood from feeding. Thanks for the feedback.
sherri I think the feed ramp is fine. However, I believe you need a longer air feed to create a type of vacuum of air to create a vortex in the chimney, hence hotter BTUs. Just a thought....It works for me.
Hi Clifton. I think to heat an inclosed space like your pool house, you'll want to make a rocket mass heater. Similar principles to this stove, but adding a mass to absorb the heat and radiate it out into the space. Here's a short intro to the concept by an expert on the subject, Paul Wheaton. ruclips.net/video/fwCz8Ris79g/видео.html
You might try not overloading the fire chamber. The reason that lowering the ramp made the fire better was because you temporarily opened up more of an air passage through that area. This allowed more air to flow into the fire chamber. Using that kind of ramp that sits outside the fire box, on top of a grate, will work, at a steep angle, but the fire will be concentrated right where the ramp meets the grating. Only the very ends of the sticks will really burn but, they WILL feed down into the existing fire.
I agree with your assessment, Al. To much fuel in the fire box. I definitely need to adjust the dimensions of fire box to allow for the slope of the feed. Thanks for the feedback.
I think, after watching your few videos of this, that right at the beginning I would build the feed chamber a little higher on the bucket and at the angle that I want my feed ramp and not even worry about a feed chamber at the very bottom. sit the whole thing on bricks as you have so that there is airflow still. use something slick (like enameled tile, as one commenter suggested) to build the extension of the feed chamber. thanks for all the information, I am looking to build one of these so I can take my wok outside and use it at the high temp that it needs to stir-fry correctly.
I think part of what could be causing the crack is the addition of vermiculite. In the last video you mentioned that the outside of the stove wasn't hot at all. By insulating the concrete you have dramatically increased the heat differential in the concrete. The inside is expanding while the outside isn't. This is putting the outside under tensile stress which concrete doesn't withstand well; especially with the addition of the vermiculite. Maybe the addition of fiberglass would help?
Good feedback, Jane. Thank you. I’ll definitely be adding an armature for my next rocket stove build with concrete and perlite. I don’t think the crack will be catastrophic now that I’ve added the banding. It functions as an expansion joint. Thanks for watching.
Seems that you discovered that the flatter fuel loading system works better; looking down the rocket we could see that the high angle had the burn only a third the way across the firebox, but flatter the fuel was right across, hence better burn and better vortex. If yo cast another rocket, I suggest two or three rings of 3/8 in rebar - one near bottom, one about half way and the third near the top. The rebar rings are best welded but a wired overlap might be OK. Enjoyed watching, and being part of your "voyage of discovery". Cheers.
Thanks Derek. I agree that flat fueling works well with this rocket stove, especially for cooking, which likes a hot, fast burn. I do plan to build a few more iterations of this stove to test a few things, a slanted top to the firebox is one of them. Thanks for the feedback.
Based on other builds I've seen, the J tube might need to be more enclosed, hence the name J Tube. Good job on this build. I like it in it's original design.
Change your base. Make your steel grate at the same angle and same level as your as your feeder ramp. This will take some extra time and work to figure out but your burn will be stronger and your wood will self feed into the fire.
That was probably part of it. The grate was definitely catching the tips of the branches. I did notice them sliding in a little, but I think the angle of the firebox needs to be changed too. Thanks for the feedback.
Crystal Fugmann definitely the grate. The bars on the grate should go in the same direction as the wood, for the wood to be able to slide in. Now the bars are across and stopping the wood. And another thing, u should grind off part of the upper lip of the inlet on the stove so the wood enters into the burnchamber instead of just to the entrance.
@@Gjorten I agree wholeheartedly the grate seems to be a major hangup,a great journey watching the development of this fun project.thank you for making these lovely bitesized morsels..
I like the basic design. I would suggest that an actual 'tunnel' for the air inlet would help give you more of the rocket effect you are looking for. The open sides and top tend to let a little too much air in. Glad you went with the lower angle for the feed tube. I would add a couple more bands around the unit to reduce the crack - and use nuts and bolts to hold it tight. Good project!
Thanks Mark. I'll try the tunnel method. I'll likely be adding nuts and bolts to the band and probably another band for extra support. Thanks for your support, by the way. :-)
Greenshortz, Great stuff, friend! Experiment, learn, have fun, and connect to make the Earth a better place, together. I love the messages you promote. Never get tired of presenting them. We need more people thinking of better ways to govern their lives, and importantly enjoy doing it.... Thanks for the recognition! I hope I returned the same motivation I received from the vids and interactions. It's been a pleasure... We are finally getting warmer days here. The concrete is turning greyer on everything I made and the test fire brick is near cured. When I return from vacation I want to torch the brick and see what happens. I'll pass on the results.... Anyone who tries this, the waiting is the hardest part. This is a fun project that can be as usefully crafty as we are creative... If you decide to make 8 different designs my suggestion, that I considered myself, is having the feed tube placed for molding with an angle higher up through the sidewall with armature above and below the opening. The bucket and pipes will need to be cut differently obviously. I had no problems using thick cardboard tube that peeled out in chunks while wet after 2-3 days perfectly fine... A friend of mine is curious to make one after we see my how well my version of material blend works out. Good ideas always spread. Im a firm supporter of "Crack-resistant" concrete after your original has held up with the heat... Enough of my chatter. Keep up the good work!
Ha! The waiting is hardest part. I hear Tom Petty right now. :-). Glad you are getting into warmer days. I remember when temps would get into the 40s and we’d break out the shorts. After teens and 20s, 42 felt like Spring. Will definitely be trying the crack resistant concrete again and the angled firebox. Thanks for all the feedback.
GreenShortz DIY more thoughts; I may shape something of the firebrick mixture to enclose the mouth. Imagine this: a tall workboot with the toe cut off so-to-say, for the overall shape after adding the stove's feed/mouth attachment. I feel the stove will burn the horizontally loaded, longer, sticks internally more as the fire crawls along the wood and forcing the air to continue along the fuel, and without buring outside the desired chamber, hopefully keeping the vaccuum effect longer before needing more fuel maintenance.... I'm excited to finally test fire the mortar/perlite sample brick under torch induced heat and minor pressure this week. The cement is turning light grey thoroughly. Make or break time... I'm so close to using my own!!
In your current design, your fuel is hung up on the front of the grill, preventing the fuel from moving into the center of the chimney, where air current is highest. As others have mentioned below, you could make an angled opening, or you could re-design the base/grill/feedramp. Instead of placing the grill on the brick base, you could connect it to the feed ramp, like an extension. The grill could extend from the ramp to the back corner of your brick foundation allowing the fuel to move all the way to the back of the chamber. This would be a little iron work instead of re-casting the whole stove. I didn't see the first video in whole, but you should consider adding some steel bands to add tension strength to the concrete. Some steel loops could also hold your rebar vertical as you place your concrete mix.
Hi! Sorry, but the obvious reason for a feeding problem in my mind is the grating. how are you gonna slide something over perpendicular stops? if there were some elevations which allowed the fuel to "flow" down the rocket stove..
Agree with the assessment. A few other comments have noted the same issue. I plan to switch the grate out for the next version of the build. Thanks for watching.
The ramp is good but the grate makes the fuel get stuck on the bottom so if you changed it to a metal plate with small holes drilled into it it would slide well
Another great video. Well done, sir! As for changing the stove to a heater? Interesting. I find part of the enjoyment of my own rocket stove is tending the fire. As for a 'self feeding heater'? I suggest you consider changing the fuel from sticks (They will ALWAYS demand constant attention) to wood pellets. The wood pellets will more readily fall down the ramp into the burn chamber. With respect I suggest you decide if you want a stove or a heater.
Thanks for the pellet suggestion. And agreed on the joy of tending the fire...one of the innate human satisfactions I think. Either that, or we are just pyros. :-) I do see your point of choosing stove or heater. Some fundamental design differences. Thanks for the feedback and ideas.
The ramp feeding into the grill plate didn't seem like it would work but a short piece of the steel channel feeding into the fire box maybe 3/4 in, may be helpful to slide longer pieces of fuel in. Just not too long so you can still clean it out. Nice work on this
I would expect your stove to have one horizontal crack, even if you made it out of refractory concrete, because the interior of the riser is going to expand relative to the exterior riser. The crack becomes a stress-relief joint, and is not necessarily a bad thing. When stoves are lined with refractory bricks, there are joints between the bricks that accommodate expansion-contraction stresses. Your joint came naturally during use. The steel strap is a good idea. On other matters, lining the interior with a coating of clay will help protect the concrete from higher temperatures. When I use perlite in the concrete mixture, I grind it down to a maximum size of coarse sand. That seems to make a stronger concrete body. I like your video series. It will be good to see what you find with the long-term durability of your stoves. For us, that may be your most important finding. Keep up the good work.
Good feedback, Julien. I need to do some more testing on the stoves. Thank you for sharing your perlite and clay ideas. I will incorporate those in future builds. Thank you for watching.
@@epiphgd4302 Grinding makes for a more uniform concrete mass, but it is also more dense than concrete with large perlite particles. The effect of perlite particle size on the thermal and strength properties should be systematically studied, but I have not yet found research on this. I use loops of old bicycle brake cable in the concrete as reinforcement. In some cases, I also use hardware cloth. Even refractory concrete can crack when it is unevenly heated.
I just did a search on the Web of Science using the keywords "concrete" AND "perlite" and found a few articles. I will get back on this subject in a few days.
I find your videos inspiring, I may very well start my own RUclips channel. Perhaps you would be interested in coaching a newbie??? I don’t know where you currently are on your rocket stove builds and feed ramps but I have a couple of ideas for you The iron grating at the bottom of your stove... use a piece with the slots flipped to assist the feed of fuel rather than hinder it sliding into the chamber On your next creation of a concrete rocket stove… I would cut the 5 gallon bucket and put your square milk jug in at the angle preferred for your feeding shoot I would be extra mindful to make sure the fire has an adequate chamber for fuel without the feeding shoot intruding into the burn chamber itself I can share drawings with you if you are interested In addition I would make some samples rather than pouring a complete stove. I would work on getting the mix of the three ingredients and the water measures just right before pouring another an entire stove. While it’s kind of fun hanging onto the edge of my seat watching how things are going to turn out it might also be fun to witness the creation of a test laboratory I know the goal is to get it just right in order to increase the installation and reduce the weight To reduce the weight you might consider aircrete
The things I've said about loading can be seen in action in 2 very short videos on my channel. The neighbors thought I was hanging around a burning broken gas-line before they brought over some drinks and joined me. I may mold a 2nd cylinder to stack on top of the stove for more height. Not the full height of the 7-gallon bucket either, like half way. I will add a few air channels on one surface for secondary oxygen between the stacks. I intend to let temperature variations expand the concrete independently throughout.
One way to improve the feed would be to turn your grate 90 degrees so that the top wires go longwise with the stove instead of crosswise with the stove. As it is, the sticks seem to catch on the grate wires. If they were going from the front to the back vs. side to side, the fuel would slide into the stove better, methinks. :)
I agree Bryan. I may actually do away with grate when I use the ramp. And use the grate without the ramp. Just means I need more rocket stoves. :-) Thanks for watching.
Smart idea - adapt the strap to secure the j-tube! But, counterbalance needed? Will the the unit pull forward without something to "anchor the back? Considering the weight of the steel feed ramp. As I watch you handle the ramp, thinking the weight isn't going to be a factor. I think you are right about the ramp-nice place to put the fuel, less messy than an unconstrained version (simply loading onto the grate). Dried sunflower stalks work nicely for fuel. When you have the unit raised up- the ramp won't be much of an obstruction when cleaning underneath.
lol. when you said that, I thought about an Alaskan rough strip just over 900 yards long (that I was tasked to remove big rocks from at what used to be known as Rainy Pass Lodge) and I thought, yeah... on a small-scale, yes! You could land a plane there, esp. after smoothing the rough edges. ;)
Cut two rectangular pieces from your leftover steel channel. Make them as wide as your steel strap, and as long as the bent strap extends outward. Drill a 17/64" hole in the center of each, for the insertion of a 1/4" bolt. Tighten these rectangular "washers" on either side of your bent straps to tension the strapping and keep the crack from opening. If it were my concrete crack, I'd feel more comfy with two straps, but then--- ;-) ---you'd need to make four rectangular "washers." Mold release wolud probably work for removing concrete from the bucket , but not for removing PVC from the concrete. Removing plastic items from molds in manufacturing processes requires the item to be tapered, and there are formulas for determining the minimum amount of taper required. Consider using stovepipe and just leaving it in place. If you don't have a scrap piece of stovepipe just the right length and are forced to purchase a whole new joint, flatten out the leftover piece and use tin snips and pop rivets to form the entire firebox. Now that I've suckered you this far in, go procure a metal 5-gallon bucket. Cut a round hole in the bottom of the bucket, and make appropriately sized notches in the side and the lid. Take the firebox-chimney assembly that you were intending to use as a concrete form and affix it to the inside of the bucket. Then fill the entire space between the bucket and the firebox-chimney with perlite. At the appropriate fabrication step, you can put bolts through the bottom of the bucket, attached by nuts on the outside, to use for pot supports. If you leave the bail on the bucket, you'll have a convenient handle for easy transportation. Take it and run, Or ditch it and dump it. But heat up some water For tea and a crumpet.
I'm thinking instead of a separate ramp, why not have a feed hole that starts somewhere in the middle and angles down to the burn chamber, with a separate hole at the bottom for air and big enough to light the fire from. And I still like the idea of building a lower rocket stove with the before mentioned angled feed hole, but no fastened bolts on top so that you could set a separate section on top of the first with just a hole running all the way through that extends the chimney for better draft. The second section would have the fastened bolts for holding the pot.
I’ve seen rocket stove designs with a mid-chimney air tube to add extra combustion air. I will try that at some point. Thanks for the feedback. Thanks for watching.
Have you ever made charcoal? I wonder if you could purpose-build a rocket stove to fit around a paint bucket, that way you could turn that excess palm into some real nice coals. Also, I wonder if filling the crack and lining the inside with some fireplace mortar would help mitigate the crack and give you more thermal efficiency.
I haven’t done charcoal, but that would be a fun exercise. I do think the mortar would help the crack. I want to observe it for a while longer as is to see what happens.
Hi Wally. I’ve done some testing with aircrete. It’s time to make this stove again with that material. Thank you for the suggestion. Thank you for watching.
Looking good. In addition recent comment, most all concrete will crack. After several hot fires, and if you aren't gonna move the thing, cracks are not a big deal. And if someone wants more asthetic, options include- breaking terracotta tiles into pieces and grout them on. Great vids! Rock on
Thanks Randy. A good friend of mine shared the same perspective on concrete always cracking. I may include a piece of chip board in the pour to provide a clean crack location.
It looks like the air vent grate is working against you by catching the wood. Turning the grate 90 degrees many work. I believe a small tin skid plate would work better at getting the wood to slide in to the central burn zone. This would help your feed ramp work better and keep the air contact with the fire deeper inside.
I think it may work better if the bottom of the steel ramp finishes at inside diameter of the fire tube and the concrete hole is cast to a suitable angle to allow the wood to slide into the center or to the back wall. actually same as what William M has said... thanks for the video as it helps others with design ideas which are great.
Good suggestion Greg. My latest rocket stove build, with the chimney flue pipe, uses a ramp angle to get the wood to the back of the firebox. It works much better. Thanks for watching.
I can’t find my hanging scale. :-) My shop is in disarray. As soon I can get it organized (and find the dang scale), I’ll get a proper weight. My estimate is about 15 pounds lighter. We’ll see how close I am. Thanks for watching.
I'm curious if your feed would work better if you found a grate that runs the other direction. I wouldn't give up on the feeder nor would I give up on the grate idea.
I agree. I think I am going to try a grate without a ramp and a ramp without a grate. I'm assuming that the drop on the ramp will supply the air gap under the wood being fed in. I think the grate is definitely stopping the angled feed, primarily because of its orientation. Rotating the grate 90 degrees would help, but I think taking it out all together would be even better. Thanks for watching and for the feedback.
I need to try soap making. Right now, I know nothing about that. :-) I’ll have to start with some research. Thank you for the suggestion. Thank you for watching.
Advice for when using the grinder to cut, the thicker wheels are intended for grinding not cutting through metal and are strongest when pressing down into them, a thin cut off wheel is much safer for making a cut like that you just can't use it like a normal grinding wheel to clean up cuts when your done, also the thin wheels make it much quicker since there is less material being removed, just make sure you let the wheel do the work not trying to force the cut through it will make your wheels last longer .
Thanks for the feedback. I agree. I’ve since watched a couple other RUclipsrs using a thin cutoff wheel and agree I was only making my job harder with the thick grinding wheel. Thanks for watching.
Just found your channel, interesting, but I think one of your issues with the feed is the direction of the bar's in your lifting grate. You have the end of your new fuel hitting what effectively are speed bumps stopping the material from sliding into your furnace burn area. Try to see if you can re-orient the grate material by 90 degrees, I think it will help in your self feeding of material. Also If I were going to build it, I would open up another channel or two for air from other directions, then you would increase your air flow through the burn chamber. Imagine you have your same 3 points like when you placed your 3 rebar supports for your pan, but now the main is your fuel entrance and the other two could be a bit smaller but from two directions. That would in my opinion help in air flow not having to come through your burn fuel, and with the grate at 90 degree change the fuel would slide into the furnace better. Note, I like the concept, maybe one day when I get my life back, I can build one myself. Further the feed ramp I think at about 45 degrees not the 60 you have, and maybe have a large supply of fuel to add in a side bucket or box, near by. I would also consider taking the time to make a lot of fuel in a short length to keep the size down making the fuel flow into the stove better. If you are going to make it again, make the fuel opening large enough to accommodate the size of your feed ramp to prevent blockage into the furnace, finally maybe a short drop off the ramp into the stove, that way you have less of a chance of stopping the flow of material.
Good feedback, Daniel. Thank you. You’re right in the grate issue. Ive gotten a lot of comments with that observation. I’ve actually just removed the grate when I use a ramp. The sticks do drop down though, so I might add the grate back. I’ll definitely be adding some secondary air channels in the next build on this stove. Thanks for watching. Hope things go well for you in the new year.
@@GreenShortzDIY Maybe two levels, one for the ramp, and a grate below for allowing the fuel to fall into the oven, but still allow lower level air flow. If you are going to build it on top of a counter, use the height to incorporate lower air flow. Another idea, put tile or wide spaced bricks as the floor, but allow air flow from under neath.
haha that's funny I just commented in the last video that you could put a strap around the outer portion of the stove and I get to this one and well it's already been done haha.
The moment you took away the ramp, the flames shot way higher! Your original build stove will work beautifully here in backwoods Philippines and you are correct, the "firewood" shown in this video is plentiful here. We just pick them up off the ground.
True. I like the way the grate works without the ramp. The ramps works better without a grate. I need to modify the firebox roof though, making it slanted, to accept more wood. What island are you on in the Philippines? Are you tropical or sub-tropical? Definitely lots of found fuel to use. You going to build one?
@@GreenShortzDIY - Thank you for taking notice of my comment. I live a little bit north of Manila . the climate here I'd say is tropical. Yes I am definitely going to copy your original build of a rocket stove. My only worry is that Perlite may not be readily available here. I have never heard of it before seeing your video.To me your original design is perfect just the way it is. Again, thank you.
You’re welcome. I try to respond to all the comments I can. The opportunity for interaction is one of the best things about RUclips. We are halfway around the world from each other, but discussing ideas and solutions. That’s pretty cool. Here are a couple ideas for substitutes for the perlite, but the stove works fine without an insulator, as you’ve observed. If you can find broken ceramic tile, it can be crushed into small bits and mixed in with the concrete. You could also try sawdust, but only mix that into a three-inch (10 cm) inner ring of the concrete right around the chimney. I haven’t done this yet, but plan to try it soon. If you use the tile, but only have a limited amount, you could do the inner ring with that as well. I’d love to know how your project goes. Keep me posted.
@@GreenShortzDIY - Thank you for the great tips. Things I really never knew before - like "it takes 28 days for concrete to properly cure". God bless, more power.
@@herminigildojakosalem8664 You're welcome. I also learned the 28-day-cure fact from the comments on my video. :-) God bless to you as well. Have a great night.
correct me if Im wrong.. a ramp works as a slide so that gravity ensures your fuel sticks are self fed into the fire.. having said that, my understanding is that the rocket principle is more on burning gas emission rather than the fuel source itself.. ergo, you'd need to have a combustion chamber deep down and centre to accumulate the gas which are then burnt at the upper level of the stove.. that's where the air holes around the edges come in to allow mixture of secondary air with gases that ignite cleaner.. trust your good sense to make this happen than.. tooddle do!
To me, what you are describing sounds more like a wood gasifier. I'm not a full expert on rocket stoves just yet, but I think the main goal is rapid airflow for oxygen boosting the burn. However, oxygen is a "gas." So maybe we are saying the same thing, different ways. I am going to try a modified version of this stove with a secondary air feed. I'm looking forward to see how that plays out. Thanks for watching.
I love your idea of the C-channel but I can't believe none of your commenters mentioned the typical J-tube on a rocket stove is at a 45 degree angle. Of course, this isn't a typical rocket stove but the info might have helped you. The steel band is a good idea but I've used those pallet straps at work and I can say there's a few problems with them. As you pointed out they bend easily, which is why we overlapped the strap and used a tightener to snug them before clamping them together. You have the band connected about 1/2 inch from the concrete and that gap will allow the band to bend when the concrete expands. Kind of defeats the purpose. The band is strong enough, but IDK how you would tighten it down to remove the slack so it won't work, sorry. My suggestion would be a large circumference ring clamp. They're cheap enough and easy enough to tighten with a simple screwdriver.
I think you are the first person on earth (at least on RUclips) taking all the suggestions seriously and try those out. But trying no harm as long as you have all the options with you. I really appreciate your sincerity in trying things and for respecting your subscribers!
Thank you, Nazeer, for saying so. I'm still learning. And a lot of good ideas and info comes in the comments section. Thank you for the encouraging words and thanks for watching.
I love the fact that you admit you don’t know and welcome criticism/critique and are willing to experiment and change.
Thanks for the encouragement Craig. RUclips is a knowledge community and the video creators don’t always have all the answers. Lots of great feedback and ideas in the comments. Thanks for watching.
i love the fact that you muted the noise from the grinder. Nobody else seems to be able to figure that out. It is so much better to not have to listen to the power tools. Major thumbs up. Thank you.
On top of this note…. Most have obnoxiously loud intros. Both of these are killers for headphone users
One thing you might want to try on the next stove to prevent cracking is waiting longer before firing it. Normal concrete usually takes 28 days to achieve the majority of its strength. Using perlite it may take even longer.
I love the way you feature comments in your successive videos!
I don't know what I would do without you-tube. Having you-tube is the best for interesting issues, it's a marvelous time to be alive. I'am truly learning a lot. And the thought of a little stove to cook with when you are away from home out camping or just taking a nature trip, I'am so grateful for the many people who are investing their ideas on you-tube. THANK YOU
I like how with this stove design is easy to add fuel with very little risk of being burned by the fire.
I like the steel band that's now holding the concrete together so the rocket stove can properly burn its fuel. The fact that you are using that band to hold up the feed ramp is a nice design detail. Keep cooking Tom!
Thanks Greg. I think I may add another band. The method I used to connect the two ends of the band allows for some expansion, which will allow the concrete to breathe a little. Thanks for the feedback.
To me, it seems your feeder is feeding the wood more to the edge of the stove instead of the middle of the stove where your fire is. Seems like the fuel feed hole should be a little higher and the upper and lower edge should have a 45 degree angle so that the wood feeds into the center of the fire chamber better.
I agree. I saw what you are seeing. I had a suggestion to angle the roof of the firebox up. That would allow the ramp to be higher and a steeper angle. Both of those things would help get the fuel into the middle of the firebox versus the edge. Thanks for all the feedback.
I wonder if you’ve considered aligning your rocket stoves with the prevailing winds. I learned that from a Thai woman who is accustomed to building her own outdoor earthen cooker for her big wok. She says it’s common practice in Thailand to point the air gap (and fuel gap) toward the incoming wind. It makes sense to me.
What rail line do you live next to? One suggestion when making a new core, don't bother with the pvc insert. Just use a heavier grade cardboard tube like the ones used for carpet rolls. Once the core is set, you can just burn the cardboard out.
Thanks for cutting out the sound of that tool running! I really hate it when I am enjoying a video and someone fires up a bunch of noise
You’re welcome. I try to spare the ears of my viewers. Thanks for watching.
This is a good design and to make it seem easy to build which means it must be easy, definitely going to be an addition to my pizza oven area which is also going to be your design
when I lived in Loa we made all our stove's from clay ,cook food ,melted rocks to make concrete, medel for tools
Methinks the grate on right angles to the feed tube is stopping the fuel from making it right into the chamber, causing burning at the front and the j tube to be quite ineffective. It's also likely to be helping the existing crack get worse as there's heat right under that part of the wall.
I found your youtube site today and I find it to be super interesting with fun projects to do with my grandson. I've been following the
videos on your rocket stove builds, you have come a long way with improvements. I was sad to see that you got a crack in your last
project stove and I had a feeling that would happen without any internal wire reinforcements.
The metal band is the best solution for that, but you really need to make it relatively tight, really tighten down on it and add a second
band down lower near the fire box opening or at least half way down.
The feed ramp, like you said is a great addition, but not necessary, but when I make one with my grandson, I will add one, as it serves
as a great place to stag some fuel and feed it in.
Again, so happy I found your site, I also love the bread oven project, another one for me and my grandson.
This is the answer to all your problems. First of all, when mixing all the ingredients use as little water as possible, such as just enough, because to much water will weaken the cement. Also, there is to much friction for dry wood to slide down a piece of rough bare steel, so simply lay some bathroom tiles on it for a non friction slide, and you will find that you can get away with much less of an angle if you want because the wood will slide very easily. Also, and a major point here, the whole slide itself should be higher, to the point that all the wood wants to head for the rear of the riser. This means that the side opening needs to be higher and not down to the bottom of the riser as you have it now. Don't worry, as the wood burns, it will fill the entire bottom, and will burn extremely well. Also, those that commented about the grate are right, as the grate bars need to run in the direction that the wood wants to slide down, otherwise the wood hits them and stops. Another major point, to prevent cracking, not only wait a month for it to dry, but the first six fires should be very small. This is very MAJOR. Light a small fire using only a few pieces of small wood, and let it burn out and then wait for the stove to cool completely, then do the same thing five more times. After that make a medium size fire and let it cool. If you do all these very simple things you will be ready to do some serious cooking.
If you want to do long fires that don’t need to be tended you would definitely benefit from a feed system. However using long sticks like that won’t funnel in easily. Make a bunch of charcoal from those dried scraps and use that initial height of the ramp. The smaller charcoal pieces will fall down into it without being forced.
P.S. make a tray to catch the ash and collect it to use in conjunction with the perlite in your next concrete mixture.
So using the ramp, I would Remove the grate to let sticks fall in deeper inside to the ground and still keep the unburned fuel segregated. Continue to use the underneath bricks elevating ramp or grate for the air path. Like you did, using the ramp to separate the unburned fuel while resting on the bricks should suspend the wood over the air-gap without the grate sufficiently, you think? Ramp OR grate, maybe not both together? Bricks underneath and dug out for the airchannel, both ways, are the key factors I noticed.
Derber Masliph Yep think also the grade prevents the wood to get in deeper, so the wood needs to be all the way into the chamber.
instead if removing the grate keep it where it is and simply add an additional layer of bricks.
Pietje NL agreed
The rails of the gate need to run with the flow of the wood not against it percents the wood from feeding if the grate was cut so the wood could slide the ramp could be any angle and not impede the feed
When you build your next stove. An idea for the reenforcement: 1. Run the rebar (pot pegs) all the way through the form and use a round hoop at the top and bottom of the form to hold in place.
Perhaps nuts and bolts might work better for the pot holders since you can fix the depth with the nut. Im inspired to make my own rocket stove. Do you think I could use clay harvested from the lake instead of cement?
Might not hurt to extend the riser about another foot or two by making another tube from the mix and putting it on top of what's there now. Also make the hole taper slightly to reflect some of the heat back downwards and help increase the updraft speed.
I'm sure someone has pointed this out already, or you have figured it out yourself. The main problem with your feed ramp is not the ramp, it's the direction of your grate. The wood cant slide in as it burns down, because it's catching on the grate underneath the feed ramp. Rotate your ramp 90 degrees and your feed ramp will work properly. Great video, thank you for the effort and instruction.
Hi Avatar. Yes, you are correct on both accounts. :-) The grate is the wrong way, and a lot of people have noticed that as well. I think I'll just eliminate the grate when I use the feed ramp. And only use the grate when it goes in flat. Thanks for the feedback.
Sewer hose clamps hooked end to end make a very easy strap.
There is nothing wrong with a crack in your stove as long as you have straps to hold it together. For that matter you could cast your stove in parts and clamp the parts together.
It would be an interesting experiment to clamp your C Channel vertically to the face of your stove so that sticks slide down into the mouth of the opening creating your J channel.
Another idea to give yourself height, cast two buckets. The lower one would be the burn chamber and the upper one would be the chimney.
Lower chamber would be made like a normal rocket stove. Although you can make the burn chamber larger...perhaps 6 or 8 inch...and with the standard side feeding channel.
Come to think of it, if the top piece is the chimney/cook top, then the bottom piece could be cast in a rectangular box to allow for creativity...even a J channel.
Hey GreenShortz,
A true J tube actually contains the the feed section on the short side of the > J where the wood will stand straight up, and slowly drop as it burns.
The burn area is along the bottom horizontal section of the J , and the fire is naturally drawn sideways from the burning wood by the draft from the chimney/heat riser.
The heat riser is along the long side of the J < . I would recommend fire brick for the feed and burn sections, and then a section of steel well pipe for the heat riser, then using a larger diameter of HVAC round duct, you can create an area to fill with vermiculite to insulate the steel pipe with makes is like a catalytic converter. then put your cement mixture around the outside of the duct if you are using outdoors for stove. If wanting to convert to a rocket heater, I would not use cement, it would not stand up to sustained high temp burning.
I haven't read the comments to find out if someone else may have made this suggestion but your grate to allow for air flow grills should run parallel with feed instead of perpendicular which causes the fuel to hang up at the mouth.
I was wondering....when you do the initial build and put your milk bottle in, could you angle it a bit to help with the slope of the J ramp thing? Would that help it instead of doing that part at a right angle?
I was wondering if you could put a flat griddle or other piece of heat conductive material on top and use the rocket stove as a cooktop?
Great job, that's a good example of a hands on research.
Thanks for watching, Allan. I appreciate the feedback.
@GreenShortz DIY A good suggestion I’d say to help your chute feed the main chamber is to make your grill runs, run vertical to your chute as apposed to laterally (parallel) and gravity will be your best friend. Keep up the great work ✌🏽.
Look at mark Thomas 6” rocket stove. He has a 4” also. Adapt his feed to the front of your cement stove. Should work very well. Great vids. Can’t wait to make on of these.
I'm loving the stove. I'm a little late to the party, but I wonder if your grate is actually hindering the autofeed.. Maybe if you had it where the grating was parallel to the feed ramp instead of perpendicular, if may autofeed a little better. My thinking is that it is catching the leading edge of the wood and stopping it.
You're never late to a rocket stove party! :-) I do think you are right. I think the grid works better without a ramp. And the ramp should work better without the grate, or at least switching the direction of the grid to the same direction as the feed. Thanks for the feedback. Thanks for watching.
With that grill running across the feeder, it will always catch what you trying to feed in. If the grill was running inline with the feeder the wood should slide in better.
Hi Glen. I had a similar thought. I’ve still got the other 2/3rds of that grill. I’ll have to make that mod when I redo this. Thanks for the suggestion.
Can you do a video showing how to install a copper pipe heat exchanger to heat hot water by natural heat siphoning process ? How much time and fuel is needed to heat 40 gallons ?
If you block the airflow from below the grate and just use that as a clean out port, you wont have to worry about the fire rising up the feed tube because the air draw will stop that from happening. This is also why a vertical feed tube for gravity feed of the sticks works without the feed tube becoming a chimney.
Interesting. Thanks for the suggestion. Thanks for watching.
to add another element to your stove use a much larger bucket to form a new outside of your stove. to create a void between the 2 buckets for you to fill with pearlite. that will allow for a super heated flue. extend the floor of your burn chamber and make a ceiling out of your firebrick, then add your ramp at the very end of the new floor of your burn chamber. Oh I just remembered something: the grate is not a good idea you needed a piece of plate steel instead. hot air on top, cold air underneath creates a vortex in flue if I remember correctly.
Thanks for the suggestion Scott. Sounds interesting.
Your grate needs to have wide slats, flat and smooth, parallel to the fuel/sticks. The grate also could have a slant to it half that of the feed ramp for another way to help product move into the firebox. I like the palm frond stems, slick on their exterior, stiff. But not much mass, so they don’t move in well. Placing a weighted sled behind them would keep them against the back of the firebox, and as they are consumed and crumple, the smooth grate may allow them to advance....
Have you ever thought about trying to do a multi burner using smaller pvc at angles to do a griddle type stove
Not yet, but that sounds cool! Thanks for sharing your idea.
The Grate impedes the use of the ramp. Maybe a perforated sheet metal interior grate? The ramp does allow for longer fuel to be added and manually pushed in as needed. Short of burning pellets of a uniform size and a shaker to help feed. I can not see where the ramp is a plus.
Agreed on the grate. I think it helps with a flat feed, but not a slanted one. I think I’ll try the ramp without the grate. Thanks for the feedback.
Excellent work, dude!
One thing that might make the self feeding easier is to make the gate run parallel to the direction of wood travel. Right now, the wood has to jump over obstacles to slide in.
Also, maybe the grate should be angled down towards the bottom and back of the rocket tube?
Good suggestions Roy. Thanks for the feedback. I’ll be making several more of these rocket stoves to incorporate all the good ideas. Thanks for sharing.
can we contol the burn rate if we put a sliding door on the air intake
What did you do with the rest of the grill grate? Cut it so the wood feeds parallel with the grate instead of perpendicular. You might have to use two sections together to get the length you want
Letting the wood slide free instead of stopping against crossbars
Hi Stephen. I still have the other piece. I think in the end I will use the grate without the feed ramp and the feed ramp without the grate. But, your observation is correct, the perpendicular bars, stopped the wood from feeding. Thanks for the feedback.
sherri
I think the feed ramp is fine. However, I believe you need a longer air feed to create a type of vacuum of air to create a vortex in the chimney, hence hotter BTUs. Just a thought....It works for me.
Thanks for the feedback Sherri. I’ll try that in my next rocket stove build. Thanks for watching.
What do you think about using one of these for a pool house? To heat 25 foot radius (50 foot diameter), how big of a core do you think may be needed?
Hi Clifton. I think to heat an inclosed space like your pool house, you'll want to make a rocket mass heater. Similar principles to this stove, but adding a mass to absorb the heat and radiate it out into the space. Here's a short intro to the concept by an expert on the subject, Paul Wheaton. ruclips.net/video/fwCz8Ris79g/видео.html
Clifton, here is a more detailed build video. ruclips.net/video/BoW-ICO83hM/видео.html
You might try not overloading the fire chamber. The reason that lowering the ramp made the fire better was because you temporarily opened up more of an air passage through that area. This allowed more air to flow into the fire chamber.
Using that kind of ramp that sits outside the fire box, on top of a grate, will work, at a steep angle, but the fire will be concentrated right where the ramp meets the grating. Only the very ends of the sticks will really burn but, they WILL feed down into the existing fire.
I agree with your assessment, Al. To much fuel in the fire box. I definitely need to adjust the dimensions of fire box to allow for the slope of the feed. Thanks for the feedback.
I think, after watching your few videos of this, that right at the beginning I would build the feed chamber a little higher on the bucket and at the angle that I want my feed ramp and not even worry about a feed chamber at the very bottom. sit the whole thing on bricks as you have so that there is airflow still. use something slick (like enameled tile, as one commenter suggested) to build the extension of the feed chamber. thanks for all the information, I am looking to build one of these so I can take my wok outside and use it at the high temp that it needs to stir-fry correctly.
I think part of what could be causing the crack is the addition of vermiculite. In the last video you mentioned that the outside of the stove wasn't hot at all. By insulating the concrete you have dramatically increased the heat differential in the concrete. The inside is expanding while the outside isn't. This is putting the outside under tensile stress which concrete doesn't withstand well; especially with the addition of the vermiculite. Maybe the addition of fiberglass would help?
Good feedback, Jane. Thank you. I’ll definitely be adding an armature for my next rocket stove build with concrete and perlite. I don’t think the crack will be catastrophic now that I’ve added the banding. It functions as an expansion joint. Thanks for watching.
Seems that you discovered that the flatter fuel loading system works better; looking down the rocket we could see that the high angle had the burn only a third the way across the firebox, but flatter the fuel was right across, hence better burn and better vortex.
If yo cast another rocket, I suggest two or three rings of 3/8 in rebar - one near bottom, one about half way and the third near the top. The rebar rings are best welded but a wired overlap might be OK.
Enjoyed watching, and being part of your "voyage of discovery". Cheers.
Thanks Derek. I agree that flat fueling works well with this rocket stove, especially for cooking, which likes a hot, fast burn. I do plan to build a few more iterations of this stove to test a few things, a slanted top to the firebox is one of them. Thanks for the feedback.
Based on other builds I've seen, the J tube might need to be more enclosed, hence the name J Tube. Good job on this build. I like it in it's original design.
Change your base. Make your steel grate at the same angle and same level as your as your feeder ramp. This will take some extra time and work to figure out but your burn will be stronger and your wood will self feed into the fire.
hi was just wondering if it might be your grate that is stopping it from feeding with the J tube
That was probably part of it. The grate was definitely catching the tips of the branches. I did notice them sliding in a little, but I think the angle of the firebox needs to be changed too. Thanks for the feedback.
Crystal Fugmann definitely the grate. The bars on the grate should go in the same direction as the wood, for the wood to be able to slide in. Now the bars are across and stopping the wood. And another thing, u should grind off part of the upper lip of the inlet on the stove so the wood enters into the burnchamber instead of just to the entrance.
@@Gjorten I agree wholeheartedly the grate seems to be a major hangup,a great journey watching the development of this fun project.thank you for making these lovely bitesized morsels..
I like the basic design. I would suggest that an actual 'tunnel' for the air inlet would help give you more of the rocket effect you are looking for. The open sides and top tend to let a little too much air in.
Glad you went with the lower angle for the feed tube.
I would add a couple more bands around the unit to reduce the crack - and use nuts and bolts to hold it tight.
Good project!
Thanks Mark. I'll try the tunnel method. I'll likely be adding nuts and bolts to the band and probably another band for extra support. Thanks for your support, by the way. :-)
You should put a dial indicator on your ramp. Following the adjustable slope it would indicate the output temperature!!
Greenshortz, Great stuff, friend! Experiment, learn, have fun, and connect to make the Earth a better place, together. I love the messages you promote. Never get tired of presenting them. We need more people thinking of better ways to govern their lives, and importantly enjoy doing it.... Thanks for the recognition! I hope I returned the same motivation I received from the vids and interactions. It's been a pleasure... We are finally getting warmer days here. The concrete is turning greyer on everything I made and the test fire brick is near cured. When I return from vacation I want to torch the brick and see what happens. I'll pass on the results.... Anyone who tries this, the waiting is the hardest part. This is a fun project that can be as usefully crafty as we are creative... If you decide to make 8 different designs my suggestion, that I considered myself, is having the feed tube placed for molding with an angle higher up through the sidewall with armature above and below the opening. The bucket and pipes will need to be cut differently obviously. I had no problems using thick cardboard tube that peeled out in chunks while wet after 2-3 days perfectly fine... A friend of mine is curious to make one after we see my how well my version of material blend works out. Good ideas always spread. Im a firm supporter of "Crack-resistant" concrete after your original has held up with the heat... Enough of my chatter. Keep up the good work!
Ha! The waiting is hardest part. I hear Tom Petty right now. :-). Glad you are getting into warmer days. I remember when temps would get into the 40s and we’d break out the shorts. After teens and 20s, 42 felt like Spring. Will definitely be trying the crack resistant concrete again and the angled firebox. Thanks for all the feedback.
GreenShortz DIY 50s with sunshine is Short's weather for sure! Backyard season finally.... Sunshine and some Mr. Petty on the radio= good day
GreenShortz DIY more thoughts; I may shape something of the firebrick mixture to enclose the mouth. Imagine this: a tall workboot with the toe cut off so-to-say, for the overall shape after adding the stove's feed/mouth attachment. I feel the stove will burn the horizontally loaded, longer, sticks internally more as the fire crawls along the wood and forcing the air to continue along the fuel, and without buring outside the desired chamber, hopefully keeping the vaccuum effect longer before needing more fuel maintenance.... I'm excited to finally test fire the mortar/perlite sample brick under torch induced heat and minor pressure this week. The cement is turning light grey thoroughly. Make or break time... I'm so close to using my own!!
Any suggestions for a solar powered fan for a mini earth battery?
I am not an expert on earth batteries. Not sure about the size of fan you’d need. Thanks for watching.
In your current design, your fuel is hung up on the front of the grill, preventing the fuel from moving into the center of the chimney, where air current is highest. As others have mentioned below, you could make an angled opening, or you could re-design the base/grill/feedramp. Instead of placing the grill on the brick base, you could connect it to the feed ramp, like an extension. The grill could extend from the ramp to the back corner of your brick foundation allowing the fuel to move all the way to the back of the chamber. This would be a little iron work instead of re-casting the whole stove.
I didn't see the first video in whole, but you should consider adding some steel bands to add tension strength to the concrete. Some steel loops could also hold your rebar vertical as you place your concrete mix.
Hi! Sorry, but the obvious reason for a feeding problem in my mind is the grating. how are you gonna slide something over perpendicular stops? if there were some elevations which allowed the fuel to "flow" down the rocket stove..
Agree with the assessment. A few other comments have noted the same issue. I plan to switch the grate out for the next version of the build. Thanks for watching.
The ramp is good but the grate makes the fuel get stuck on the bottom so if you changed it to a metal plate with small holes drilled into it it would slide well
Another great video. Well done, sir!
As for changing the stove to a heater? Interesting.
I find part of the enjoyment of my own rocket stove is tending the fire.
As for a 'self feeding heater'?
I suggest you consider changing the fuel from sticks (They will ALWAYS demand constant attention) to wood pellets.
The wood pellets will more readily fall down the ramp into the burn chamber.
With respect I suggest you decide if you want a stove or a heater.
Thanks for the pellet suggestion. And agreed on the joy of tending the fire...one of the innate human satisfactions I think. Either that, or we are just pyros. :-) I do see your point of choosing stove or heater. Some fundamental design differences. Thanks for the feedback and ideas.
The ramp feeding into the grill plate didn't seem like it would work but a short piece of the steel channel feeding into the fire box maybe 3/4 in, may be helpful to slide longer pieces of fuel in. Just not too long so you can still clean it out. Nice work on this
Say bro...i know you know...but your a smart builder 👍
I would expect your stove to have one horizontal crack, even if you made it out of refractory concrete, because the interior of the riser is going to expand relative to the exterior riser. The crack becomes a stress-relief joint, and is not necessarily a bad thing. When stoves are lined with refractory bricks, there are joints between the bricks that accommodate expansion-contraction stresses. Your joint came naturally during use. The steel strap is a good idea.
On other matters, lining the interior with a coating of clay will help protect the concrete from higher temperatures.
When I use perlite in the concrete mixture, I grind it down to a maximum size of coarse sand. That seems to make a stronger concrete body.
I like your video series. It will be good to see what you find with the long-term durability of your stoves. For us, that may be your most important finding. Keep up the good work.
Good feedback, Julien. I need to do some more testing on the stoves. Thank you for sharing your perlite and clay ideas. I will incorporate those in future builds. Thank you for watching.
@@epiphgd4302 Grinding makes for a more uniform concrete mass, but it is also more dense than concrete with large perlite particles. The effect of perlite particle size on the thermal and strength properties should be systematically studied, but I have not yet found research on this. I use loops of old bicycle brake cable in the concrete as reinforcement. In some cases, I also use hardware cloth. Even refractory concrete can crack when it is unevenly heated.
I just did a search on the Web of Science using the keywords "concrete" AND "perlite" and found a few articles. I will get back on this subject in a few days.
I find your videos inspiring, I may very well start my own RUclips channel. Perhaps you would be interested in coaching a newbie???
I don’t know where you currently are on your rocket stove builds and feed ramps but I have a couple of ideas for you
The iron grating at the bottom of your stove... use a piece with the slots flipped to assist the feed of fuel rather than hinder it sliding into the chamber
On your next creation of a concrete rocket stove… I would cut the 5 gallon bucket and put your square milk jug in at the angle preferred for your feeding shoot
I would be extra mindful to make sure the fire has an adequate chamber for fuel without the feeding shoot intruding into the burn chamber itself
I can share drawings with you if you are interested
In addition I would make some samples rather than pouring a complete stove.
I would work on getting the mix of the three ingredients and the water measures just right before pouring another an entire stove. While it’s kind of fun hanging onto the edge of my seat watching how things are going to turn out it might also be fun to witness the creation of a test laboratory
I know the goal is to get it just right in order to increase the installation and reduce the weight
To reduce the weight you might consider aircrete
You should be using all that leaf litter as your tinder!
I also wonder what results you would get from doubling the length of the chimney.
Thanks for the feedback, Jeff. I’ll have to experiment with a taller chimney. I do plan to make a proper rocket stove soon. Thanks for watching.
The things I've said about loading can be seen in action in 2 very short videos on my channel. The neighbors thought I was hanging around a burning broken gas-line before they brought over some drinks and joined me. I may mold a 2nd cylinder to stack on top of the stove for more height. Not the full height of the 7-gallon bucket either, like half way. I will add a few air channels on one surface for secondary oxygen between the stacks. I intend to let temperature variations expand the concrete independently throughout.
Where are these videos I would like to see them please
One way to improve the feed would be to turn your grate 90 degrees so that the top wires go longwise with the stove instead of crosswise with the stove. As it is, the sticks seem to catch on the grate wires. If they were going from the front to the back vs. side to side, the fuel would slide into the stove better, methinks. :)
I agree Bryan. I may actually do away with grate when I use the ramp. And use the grate without the ramp. Just means I need more rocket stoves. :-) Thanks for watching.
Smart idea - adapt the strap to secure the j-tube! But, counterbalance needed? Will the the unit pull forward without something to "anchor the back? Considering the weight of the steel feed ramp. As I watch you handle the ramp, thinking the weight isn't going to be a factor. I think you are right about the ramp-nice place to put the fuel, less messy than an unconstrained version (simply loading onto the grate). Dried sunflower stalks work nicely for fuel. When you have the unit raised up- the ramp won't be much of an obstruction when cleaning underneath.
I really do think a plane could land on that steel. It did seem to be fairly sturdy at the base. Thanks for the feedback.
lol. when you said that, I thought about an Alaskan rough strip just over 900 yards long (that I was tasked to remove big rocks from at what used to be known as Rainy Pass Lodge) and I thought, yeah... on a small-scale, yes! You could land a plane there, esp. after smoothing the rough edges. ;)
Cut two rectangular pieces from your leftover steel channel. Make them as wide as your steel strap, and as long as the bent strap extends outward. Drill a 17/64" hole in the center of each, for the insertion of a 1/4" bolt. Tighten these rectangular "washers" on either side of your bent straps to tension the strapping and keep the crack from opening. If it were my concrete crack, I'd feel more comfy with two straps, but then--- ;-) ---you'd need to make four rectangular "washers."
Mold release wolud probably work for removing concrete from the bucket , but not for removing PVC from the concrete. Removing plastic items from molds in manufacturing processes requires the item to be tapered, and there are formulas for determining the minimum amount of taper required. Consider using stovepipe and just leaving it in place. If you don't have a scrap piece of stovepipe just the right length and are forced to purchase a whole new joint, flatten out the leftover piece and use tin snips and pop rivets to form the entire firebox.
Now that I've suckered you this far in, go procure a metal 5-gallon bucket. Cut a round hole in the bottom of the bucket, and make appropriately sized notches in the side and the lid. Take the firebox-chimney assembly that you were intending to use as a concrete form and affix it to the inside of the bucket. Then fill the entire space between the bucket and the firebox-chimney with perlite. At the appropriate fabrication step, you can put bolts through the bottom of the bucket, attached by nuts on the outside, to use for pot supports. If you leave the bail on the bucket, you'll have a convenient handle for easy transportation.
Take it and run,
Or ditch it and dump it.
But heat up some water
For tea and a crumpet.
If your rebuilding it anyway you could use grinder to put angle opening
I'm thinking instead of a separate ramp, why not have a feed hole that starts somewhere in the middle and angles down to the burn chamber, with a separate hole at the bottom for air and big enough to light the fire from. And I still like the idea of building a lower rocket stove with the before mentioned angled feed hole, but no fastened bolts on top so that you could set a separate section on top of the first with just a hole running all the way through that extends the chimney for better draft. The second section would have the fastened bolts for holding the pot.
I’ve seen rocket stove designs with a mid-chimney air tube to add extra combustion air. I will try that at some point. Thanks for the feedback. Thanks for watching.
Have you ever made charcoal? I wonder if you could purpose-build a rocket stove to fit around a paint bucket, that way you could turn that excess palm into some real nice coals.
Also, I wonder if filling the crack and lining the inside with some fireplace mortar would help mitigate the crack and give you more thermal efficiency.
I haven’t done charcoal, but that would be a fun exercise. I do think the mortar would help the crack. I want to observe it for a while longer as is to see what happens.
Thanks for another great video!
Why not thread the hook arrangement at the ramp hole end so you can adjust the angle of the ramp?
Nice idea Nick. I could make that happen with some all-thread. I just happened to have a tent stake on hand. Thanks for sharing.
Have you considered using aircrete as the material for the rocket stove?
Hi Wally. I’ve done some testing with aircrete. It’s time to make this stove again with that material. Thank you for the suggestion. Thank you for watching.
Looking good. In addition recent comment, most all concrete will crack. After several hot fires, and if you aren't gonna move the thing, cracks are not a big deal. And if someone wants more asthetic, options include- breaking terracotta tiles into pieces and grout them on. Great vids! Rock on
Thanks Randy. A good friend of mine shared the same perspective on concrete always cracking. I may include a piece of chip board in the pour to provide a clean crack location.
turn the grate so fuel will slide in easier?
Thanks for the suggestion, Dale. I’m going to give that a try. Thanks for watching.
It looks like the air vent grate is working against you by catching the wood. Turning the grate 90 degrees many work. I believe a small tin skid plate would work better at getting the wood to slide in to the central burn zone. This would help your feed ramp work better and keep the air contact with the fire deeper inside.
Thanks for the feedback, Will. I’m going to make some tweaks on this in the coming weeks. Thanks for watching.
I think it may work better if the bottom of the steel ramp finishes at inside diameter of the fire tube and the concrete hole is cast to a suitable angle to allow the wood to slide into the center or to the back wall. actually same as what William M has said... thanks for the video as it helps others with design ideas which are great.
Good suggestion Greg. My latest rocket stove build, with the chimney flue pipe, uses a ramp angle to get the wood to the back of the firebox. It works much better. Thanks for watching.
Your grate is perpendicular to the material, stopping it from sliding inward.
If you turn them 90 degrees the material may slide in better
I’m doing it! Thanks for the videos
Awesome! Good luck with your build. Thank you for watching.
Great video , your a natural
Thanks for the encouragement Yvon. I appreciate it. :-)
What's the weight difference?
I can’t find my hanging scale. :-) My shop is in disarray. As soon I can get it organized (and find the dang scale), I’ll get a proper weight. My estimate is about 15 pounds lighter. We’ll see how close I am. Thanks for watching.
Try your bathroom scales?
The answer will be in today's video. :-)
How about using a welded steal rebar framework added to the structure
Hi Gary. A good suggestion. I've got some concrete mesh I plan to use as an armature for the next build. Thanks for the feedback.
I totally want to try making this!
Awesome. Let me know how it goes!
I'm curious if your feed would work better if you found a grate that runs the other direction. I wouldn't give up on the feeder nor would I give up on the grate idea.
I agree. I think I am going to try a grate without a ramp and a ramp without a grate. I'm assuming that the drop on the ramp will supply the air gap under the wood being fed in. I think the grate is definitely stopping the angled feed, primarily because of its orientation. Rotating the grate 90 degrees would help, but I think taking it out all together would be even better. Thanks for watching and for the feedback.
GreenShortz DIY this whole idea is interesting to me. Did you find out the weight difference between this version and the last?
The weight answer will be in today's video. :-)
GreenShortz DIY I better make sure I’m subbed!
gotta place the burning grate at the same angle as the feed tube?
Thanks for the suggestion. I’m going to try that in one of the next rocket stove builds. Thanks for watching.
When I was 6, I mentioned to my dad that the sidewalk has a crack. My dad replied, " Don't worry it will be fine, you have a crack too".
Nao faz fumaça?
You can use the ash to make lye for homemade soap.
I need to try soap making. Right now, I know nothing about that. :-) I’ll have to start with some research. Thank you for the suggestion. Thank you for watching.
Advice for when using the grinder to cut, the thicker wheels are intended for grinding not cutting through metal and are strongest when pressing down into them, a thin cut off wheel is much safer for making a cut like that you just can't use it like a normal grinding wheel to clean up cuts when your done, also the thin wheels make it much quicker since there is less material being removed, just make sure you let the wheel do the work not trying to force the cut through it will make your wheels last longer .
Thanks for the feedback. I agree. I’ve since watched a couple other RUclipsrs using a thin cutoff wheel and agree I was only making my job harder with the thick grinding wheel. Thanks for watching.
Just found your channel, interesting, but I think one of your issues with the feed is
the direction of the bar's in your lifting grate. You have the end of your new fuel
hitting what effectively are speed bumps stopping the material from sliding into your furnace burn area. Try to see if you can re-orient the grate material by 90 degrees, I think it will help in your self feeding of material.
Also If I were going to build it, I would open up another channel or two for air from other directions, then you would increase your air flow through the burn chamber. Imagine you have your same 3 points like when you placed your 3 rebar supports for your pan, but now the main is your fuel entrance and the other two could be a bit smaller but from two directions. That would in my opinion help in air flow not having to come through your burn fuel, and with the grate at 90 degree change the fuel would slide into the furnace better. Note, I like the concept, maybe one day when I get my life back, I can build one myself. Further the feed ramp I think
at about 45 degrees not the 60 you have, and maybe have a large supply of fuel to add in a side bucket or box, near by. I would also consider taking the time to make a lot of fuel in a short length to keep the size down making the fuel flow into the stove better. If you are going to make it again, make the fuel opening large enough to accommodate the size of your feed ramp to prevent blockage into the furnace, finally maybe a short drop off the ramp into the stove, that way you have less of a chance of stopping the flow of material.
Good feedback, Daniel. Thank you. You’re right in the grate issue. Ive gotten a lot of comments with that observation. I’ve actually just removed the grate when I use a ramp. The sticks do drop down though, so I might add the grate back. I’ll definitely be adding some secondary air channels in the next build on this stove. Thanks for watching. Hope things go well for you in the new year.
@@GreenShortzDIY Maybe two levels, one for the ramp, and a grate below for allowing the fuel to fall into the oven, but still allow lower level air flow. If you are going to build it on top of a counter, use the height to incorporate lower air flow. Another idea, put tile or wide spaced bricks as the floor, but allow air flow from under neath.
haha that's funny I just commented in the last video that you could put a strap around the outer portion of the stove and I get to this one and well it's already been done haha.
great minds, Tyson...great minds. :-) Thanks for watching and for your comments.
Ireland:
Simple is good. The most successful things in life are simplest.
No ramp, and I would buy it.
The moment you took away the ramp, the flames shot way higher! Your original build stove will work beautifully here in backwoods Philippines and you are correct, the "firewood" shown in this video is plentiful here. We just pick them up off the ground.
True. I like the way the grate works without the ramp. The ramps works better without a grate. I need to modify the firebox roof though, making it slanted, to accept more wood. What island are you on in the Philippines? Are you tropical or sub-tropical? Definitely lots of found fuel to use. You going to build one?
@@GreenShortzDIY - Thank you for taking notice of my comment. I live a little bit north of Manila . the climate here I'd say is tropical. Yes I am definitely going to copy your original build of a rocket stove. My only worry is that Perlite may not be readily available here. I have never heard of it before seeing your video.To me your original design is perfect just the way it is. Again, thank you.
You’re welcome. I try to respond to all the comments I can. The opportunity for interaction is one of the best things about RUclips. We are halfway around the world from each other, but discussing ideas and solutions. That’s pretty cool. Here are a couple ideas for substitutes for the perlite, but the stove works fine without an insulator, as you’ve observed. If you can find broken ceramic tile, it can be crushed into small bits and mixed in with the concrete. You could also try sawdust, but only mix that into a three-inch (10 cm) inner ring of the concrete right around the chimney. I haven’t done this yet, but plan to try it soon. If you use the tile, but only have a limited amount, you could do the inner ring with that as well. I’d love to know how your project goes. Keep me posted.
@@GreenShortzDIY - Thank you for the great tips. Things I really never knew before - like "it takes 28 days for concrete to properly cure". God bless, more power.
@@herminigildojakosalem8664 You're welcome. I also learned the 28-day-cure fact from the comments on my video. :-) God bless to you as well. Have a great night.
Looking good. I watched 80% of this and got interrupted. Not sure how I missed commenting. We need to make a stand for that.
I like the stand idea, Chad. I want to have one of these on the deck for cooking. A classy stand would help sell the wife. :-) Thanks for the idea.
a j tube is for long burn times .use chips or pellets ? the fuel mass will have more surface to burn .gl
correct me if Im wrong.. a ramp works as a slide so that gravity ensures your fuel sticks are self fed into the fire.. having said that, my understanding is that the rocket principle is more on burning gas emission rather than the fuel source itself.. ergo, you'd need to have a combustion chamber deep down and centre to accumulate the gas which are then burnt at the upper level of the stove.. that's where the air holes around the edges come in to allow mixture of secondary air with gases that ignite cleaner.. trust your good sense to make this happen than.. tooddle do!
To me, what you are describing sounds more like a wood gasifier. I'm not a full expert on rocket stoves just yet, but I think the main goal is rapid airflow for oxygen boosting the burn. However, oxygen is a "gas." So maybe we are saying the same thing, different ways. I am going to try a modified version of this stove with a secondary air feed. I'm looking forward to see how that plays out. Thanks for watching.
sure mate...glad to help anyway I can... if at all..:-)
I love your idea of the C-channel but I can't believe none of your commenters mentioned the typical J-tube on a rocket stove is at a 45 degree angle. Of course, this isn't a typical rocket stove but the info might have helped you.
The steel band is a good idea but I've used those pallet straps at work and I can say there's a few problems with them. As you pointed out they bend easily, which is why we overlapped the strap and used a tightener to snug them before clamping them together. You have the band connected about 1/2 inch from the concrete and that gap will allow the band to bend when the concrete expands. Kind of defeats the purpose. The band is strong enough, but IDK how you would tighten it down to remove the slack so it won't work, sorry. My suggestion would be a large circumference ring clamp. They're cheap enough and easy enough to tighten with a simple screwdriver.
You could use chicken or rabbit wire to wrap your stove and then your clamps around it and probably won't fall apart or separate any further.