If you put aluminum powder into a mix with water glass. The high base environment will produce hydrogen that will foam up and make an aircrete like material. The hydrogen will escape from the material soon after leaving a safe fire proof foam. But your max temp with waterglass will be around 2200F
Into Evans uses pearlite mixed with a small amount slurry of bentonite to make an insulated castable for the riser. Using the waterglass and dry bentonite might just be an improvement.
I so wish that those who help with low income folk like myself and my husband, we're both disabled but we could manage a wood stove like this, could install something like this in our homes rather than throw money to oil companies, to electric companies...it would be such a blessing!
We installed a "regular" wood burning cook stove, and it is a real blessing. It saves on propane and electric expenses, but it is a lot of work. Answersfromgod.com/?youtube=NcVlb-z6Y94
Just for the record the water glass is reacting with carbon dioxide heat just speeds up the reaction. The crust you see is silicon dioxide and sodium carbonate.
The main purpose of a rocket mass heater is to transmit as much heat from the burning into the mass - allowing for that heat to migrate into living space. Theoretically, you want the smoke ultimately leaving the chimney to the outdoors to be cool. Aircrete, perlitecrete and other kinds of air entraining methods will act as an insulator, not as a reservoir for heat - meaning you'll end up losing most of your heat out the chimney. You can buy bags of refractory cement, but the most cost effective method I've used is adding a good shovelful of fire clay to each 80 lb bag of ready mix concrete. Or, if you are laying in stones, you add the fire clay to a similar weight of mortar mix. I've built a pizza oven and I can assure you that thing gets hot. I've had no degrading of any portland cement product I've used.
If this is working right it will get way to hot for normal cement. Cement disintegrates at about 1000 F The riser in the stove can reach 1900. Nearly double the 1000 degrees of a pizza oven.
@@ghz24 ... Yes in part. I have a steel angle iron in my brick oven that deformed slightly in the heat. I take this to mean the top of the pizza oven reached close to 1900F. Still, even with that heat, the portland/clay mortar joints between the oven's red clay bricks have not been affected. Disintegration certainly has not happened. By comparison then, for a rocket mass heater, a well designed, heat resistant firebox is necessary, but adding clay to concrete mix for the mass - often benches - will be adequate to sustain the high temperatures
Good stuff. I was looking into how I could use aircrete in a rocket mass heater and here it is. Made the foam generator got some decent aircrete now on the the water glass. I was thinking starlite or the glue baking soda cornstarch mix might also be an option.
Suggestion procedure: You might pre=make sections of aircrete riser with groove on top ide and lip on bottom to interlock. Then take cured unit drop in tank of water glass solution to coat all surfaces. Then coat with Portland cement and stack up sections and finish bonding water glass with fire.. Then determine temperature and cooking time to finished product.
Rocket heaters can easily be made lightweight and portable. Rocket mass heaters, as the name implies, can not. Once you remove the mass from a rocket mass heater, it becomes a simple rocket heater. Conversely, a rocket mass heater is simply a rocket heater with a massive thermal battery attached to it to store excess heat. I didn't write this to put you down. I just want to highlight the differences between rocket heaters and rocket mass heaters. You built an awesome rocket heater. Without the thermal battery, it is not a rocket mass heater. I do like the creativity in using aircrete for the insulated riser. This is an important part of making an efficient rocket heater.
Have you given any thought to possibly installing the actual burn chamber of the rocket heater outdoors? The children could be inside while the high heat fire would be outside and away from the small structure. You could route the flu chamber to wind inside of the cabin to produce heat with the threat of a ultra hot fire on the outside.
If you were to put that glass with the aircrete in a vacuum environment and then alternate between vacuum and refreshing you could probably get the absorption rate way up there
@@vanderumd11 but where's the fun in that? ..not to mention, 5 bags for 1 rocket stove? Will you be flying it to the moon? Considering the mix, I was thinking maybe ½ a bag would make a nice sized rocket stove..
I am glad your HVAC system is more to your liking. This does not mean that your wood produces more energy than your neighbor's. Your system EXTRACTS more energy from your stove in the manner you have designed it. Your residence is probably better insulated and your comfort level may also be different than others. Some have poor insulation, others might feel that a temperature of 78 degrees is what makes them feel comfortable. You extract more from a chord of wood by heating solid masses than someone else's heating system that utilizes a fireplace for heating their living space. It all has to do with the degree of insulation of the living space and the method of extraction of heat from the fuel(wood) that is burned and COMFORT LEVEL for different people. I noticed you looked comfortable inside your house dressed in your overcoat. Someone else might feel more comfortable being in a t-shirt while indoors. Your comfort level is obviously different. Someone else might prefer more humidity in his indoor space than you do. Insulate your house better and extract heat more efficiently from your fuel within the parameters of your comfort zone.
Thanks for publishing this info! Refractory mixes are not hard to find, but I hadn't considered the weight. I just assumed I'd have to put up with a terribly heavy set-up. Thanksfully, I found this before I was about to start on my own.
The thing is, you won't have to let the fire burn into the night, you can time the burn to end before you want to get to bed, the bench will keep your kids from freezing.
You should take advantage of the size of your segments! Use a vacuum chamber and submerge your riser segment for permeation. You'll be able to use a more concentrated mix of sodium silicate and slow cure it. I'd bet that your overall product would be a lot closer to what you want.
Great idea - THANKS! Really, really helpful. By the way, yes the heat blasts off the water but it's the CO2 gas from the combustion process that does the curing of the water glass (from torch combustion, or gas (not electric) oven, or just use dry ice from the local welding supply - you get it). Air curing to glass is pretty slow only because ordinary outdoor air is only about 0.04% CO2. That is, it is not the heat that makes the solution into glass. Most off the shelf water glass solution is about 40% silicate in suspension and the rest is in fact water, so the expansion to the perlite-like appearance is caused by steam escaping from the heated water only. But who cares - the end results are perfect! Thanks again!
have you ever done a pressure test on aircrete like you use to do on the bridge concrete?..i guess what i am getting at is...have you come up with a load bearing mix for building structure walls in homes, etc.?
I built 6 rocket mass heaters (rebuilt it 6 times) in a dome I had over two winters in Wisconsin. I learned a great deal about them and how they fail. If a riser has a catastrophic failure, it can drop materials into the burn chamber and the active flame comes out the inlet of the RMH. It happened to me and luckily I was sitting here there and I had plenty of water from my aquaponics system to extinguish the flame. I absolutely love RMHer's. I was able to heat my 20' dome that only had two layers of 6mil plastic to 75 degrees each night. As I remember the coldest night was -23 degrees F. And, the most wood I ever used in a night was 3 paper grocery bags of pallet wood. Nothing better than cherry tomatoes in late January in Wisconsin! I miss my dome!
“If a riser has a catastrophic failure, it can drop materials into the burn chamber and the active flame comes out the inlet of the RMH. It happened to me and luckily I was sitting here there and I had plenty of water from my aquaponics system to extinguish the flame.” And this is the problem. The idea is awesome. But Paul Wheaton doesn’t seem willing to admit the flaws. You cannot get insurance on your house for this reason. Codes will not allow the RMH for this reason. They are being built by AMATEURS which is fine, but there is no accepted design parameters, no UL testing. It’s an awesome thing, until it isn’t.
@@brucea550 these things are slowly changing thankfully. There are stoves getting approval that can be run through a mass. The legal one I know right now is like $2500, which is a lot. But if you have an expensive home it's worth it to get insured
@@priestesslucy I’m not sure what you mean about stoves that can be run through a mass. The system has to be designed as a system, not a factory woodstove and a home built mass. Could you maybe mention a source for what you know of? I do know there are companies making the actual prefab riser that you can buy for your RMH fabrication, but still not a complete UL system that will satisfy codes or insurance underwriters. I’d LOVE to find one! Paul W. makes ‘I know of a guy’ comments but never any actual facts or sources. Even if you have a non-expensive home, having homeowners insurance provides you with liability protection if, for example, someone gets hurt on your property. It’s not just about ‘if the house catches fire’. All these uninsured folks are living on ‘a wing and a prayer’, and their only protection from potentially getting sued is their own poverty- can’t get blood from a turnip. It’s also highly irresponsible putting these experimental heaters in occupied spaces where people sleep. Please don’t misunderstand, I think experimental stuff is great, and I have now built an RMH in a detached garage, with the firebox separated from the rest of the structure by a concrete wall. So far I like it. But it’s clearly experimental, and I wouldn’t put one in my house.
An old "recipe"for build walls with refractory bricks,is a mix of ashes and portland cement.Maybe that mixture results a even better special heat resistant air crete.
Hi Julie and Darwin- I watch both your channels avidly. -Im living a similar life down in NZ. Why Im here is to ask If I might pay homage to you two and show some snips of this video? to introduce you and show how im making my reaction chamber insulation for my plastic depolymerisation machine- turning waste plastic into diesel fuel
You are going through more work than you have to,I am a ticketed refractory bricklayer,and have been relinning lime kilns,power and recovery boilers,furnaces etc for 20 years.all you need is a bag of lightweight castable.ther is no abrasion so a llightweight castable should work no problem and a bag should only cost you 20 30 bucks,we use it by the pallet and b train.
not sure if you check the comments mate but it might be useful to try vacuum impregnation similar to how you use a vacuum to get epoxy into fibreglass or carbon fibre.
It's a shame that they stopped using the shuttle you could have made cheaper tiles on the bottom for re-entry and probably better. Well done professor honey do carpenter
Well, I thank him for thinking in the future and sharing for free. Our world is moving in a new direction, freeing us with technology... you may want to look into blockchain technology, it is the way of the future for contracts of all kind$.
they invented a plastic in the eighties that could take an acytiline torch they could have dipped the entire shuttles into they didnt award the contract to the man and ruined his life
Getting a patent is easy. Showing that your admixture remains stable over time and does not fall apart is a different thing. Building new system might be easy for some. Building something that lasts and does not show material defect with the passage of time is a different thing. As the saying goes in the advertising business: "-Charlie, we don't want a tuna with good taste; we want a tuna that tastes good!"
-48 a few days ago with more to come, a bit tired of those $250 a month natural gas bills. I've had many wood stoves over the years, many bought and built. The one thing I've learned is burning green wood is when creosote can become a problem. So as long as you don't burn green wood you hopefully won't that problem. ( However in a wood stove, 3 dry logs and 2 green logs makes for a fire that isn't as hot. )
We burn really dry wood but it is soft wood. We only grow soft wood in our area, pine and douglas fir. We had creosote buildup every six weeks in our conventional wood cook stove. The new rocket stove hasn't had any creosote with the same wood now that we have the aircrete chimney on it for insulation.
@@dirtpatcheaven Have you tried burning pallet wood? I picked up 250 free pallets, many are built with hardwood, these burn very very "HOT" so doesn't take a whole bunch to warm the double garage up. I usually run a skill saw, inside the stringers on each side, of the pallet, then only have the middle nails to deal with. I honestly believe you're mass heater should have been about 1/2 the size, as big as it is, as you live in a tiny house. ( It would also take up less space. "It must get horribly "HOT" up-top/ in the loft, as hot air rises. "Just my thinking" I find the problem with wood burning is it is incredibly hard to control temperatures. There is another style of wood heating system I tried and really liked, however when it went below -10, it couldn't keep the place warm even when burning massive amounts of wood. Check this out; --ruclips.net/video/v_i5Cj2LSUo-/видео.html- - I'm sure you're buddy could rig one of these up for you, the thing literally functions like a natural gas furnace, with a thermostatic heat controlled fan. I built one, just to test, and really really liked it, but because it gets so cold here, it would have burned to much wood, to be efficient.- ruclips.net/video/2mZM74qPVrM/видео.html
you need not heat water glass to harden it. it hardens due to co2 absorption. it hardens with your torch because combustion causes co2 to be created. it will harden on its own with time as it gets it co2 from the air or you can force it in seconds with co2 gas injection from a tank and it will not expand like it does when you head it. I use it for making sand casting cores for molten metal. I'm going to try just perlite wetted lightly with with water glass the rammed in a form and injected with co2.
Kilns and pottery wheels are needed, butnat times well most cant afford....i am one so we want to grow our craft and way of using pottery for our needs. Itll keep us busy to fire our grandsons projects easily
There is a major oversight I will attempt to explain. Any and all materials have a couple of important properties as they pertain to RMH's . One is thermal storage capacities known as "K" value and the other is insulation value known as "R" value. The two properties are inverse to each other meaning if it is a good insulator its a terrible heat storage material or to say it another way would be the more R then the less K or the more K the less R. being that RMH work with principal of heat storage. Making a RMH out of foam aircrete will greatly reduce the very principal RMH are built on and that is heat storage. Thermal capacity material charts are available on line to view. water is the unit of measure for K value and water is 1k value stone is .2 thus water holds 5 times more heat than stone pound for pound but stone is more dense ( water is 63 pounds per cubic foot while stone is 95) thus by area water stores 3.26 more heat than solid stone (not gravel or rocks with spaces). concrete is equal to solid stone in heat capacity for storage but when you add the air bubbles the insulation value of the concrete goes way up and the ability to store heat known as K value goes way down defeating the main functioning principal of the RMH , any questions?
So good application for the hot flue gas insulating components but bad idea in the thermal transfer sections... Makes a better cast insulating ring / penetration assy for the flue pipe though, assuming the physicals are there or can be boosted with glass/ceramic/wire or whatever. Good explanation. Thanks.
Good points Van Powell. Ideally though a good system utilizes insulators in the right key points to also protect system componets from premature failure while it maximizes the burn, transfers, then captures, stores and then releases the heat in as efficent a manner to conserve the resources. Combustion of all materials and gasses, transfer of heat to a temporary storage medium, then as slow as possible a release of heat from the storage medium all with a goal of safety in mind. Safe, light, and cheap Insulators in the right points of such a system is a goal for many an RV and Tiny Home building hobbiest such as myself. So this option looks promising and worth some experimentation for those of us knowledgeable and cautious adults. Used as a thinner layer outside a metal flue instead of as the flue or maybe even adding some steel tubeing to the inner surface partually within the mold to store and funnel the hit gases while protecting outer surfaces.
new skool/old skool: now we understand and agree/see cleaner burns with highet draft created only by higher temperatures in primary and secondary burn chambers, created only by insulation (not resistance). With higher draft and less smoke, we can build bigger and longer resistance channels after the burn chamber before venting outside. Again, ANY resistance/induction of the primary and secondary burns creates more smoke and residue and slows the draw/output of air, eats more wood per calorie output. Seems counter-intuitive at first, but it is how it is at this point, sorry about your 30+ years' experience. We knew it thousands of years ago and are only realizing it again. My advice to 'experts:" stay more interested in your topic than your being right
Howdy. I respect what you are doing but would like to comment on something I think I heard you say in re adding water glass (silicate) to the original matrix - as opposed to applying it post-cure by immersion or cement / silicate application afterwards. I offer the following from hard experience that too high a concentration of water glass in the original matrix (may) ultimately expand - as it appears to in your surface ablation demonstration - and cause failures (cracking) over time. From my observation, differential internal stress(es) cause expansion in the cure(ing) matrix - which goes on for (months) - across heating/cooling cycles normal to your intended use as a (flue pipe). Stated another way, your insulation value is preserved until essentially mechanical stress in the matrix causes failure - at which point you get a hot failure which you may not even notice unless you are present to hear the crack. (My) first symptom was the sudden development of a vertical hot spot which translated to the exterior (steel) form and began to heat radically. Fortunately, I was awake and heard/felt the temperature change in the system and smelled the paint over heating. More fortunately the failure did not occur near the roof penetration. Diagnosing it required disassembly and destruction though - whereupon the material looked quite normal on either side of the vertical crack. The remaining material was still quite functional and without signs of soot, carbon, decomposition, chalking or other chemical failure (per se) and did not exhibit voids that might have indicated an air inclusion or water pocket (i.e. steam fracture). The cross section was to spec and not appreciably thinner in the failure area. The matrix had simply mechanically failed and permitted heat migration to an area that was not acceptable. In all, the remedy was simple as I had likewise taken a modular approach to the design. I was fortunate to have cast more sections than I needed and simply swapped the failed section out. It has not failed since though I encourage others to really think ahead about mechanical issues and not build complex designs without really thinking through issues that may induce a lot of variability across thermal stress internal to the (pipe) - such as in way of bends and long pipe runs, or where back pressure(wind) or sudden cooling via rain runoff and condensation may work against you over time. Milled or chopped glass fiber can mitigate stress failures but need to be carefully dispersed in the matrix to avoid balling and inconsistencies. Shorter fiber lengths "flow" better when pouring/forming your shape. It is strong argument however for using ceramic wool (not just fiberglass building insulation) and an air gap in all wall and roof penetrations though to provide an extra layer of safety despite how well your matrix performs. Likewise - folks need to use all-steel forms (no aluminum - ever), as i know you have shown in your videos. Thin wall dryer ducting is a poor compromise to heavier gauge wood stove piping. All welded sleeved or flanged construction is safer yet and lasts longer (at the compromise of weight of course). Otherwise to the topic, I have found that box-store grade perlite, vermiculite, and even sawdust shavings and other materials can contain widely variable percentages of "fines" that (can) affect the quality of your matrix. Some fines are essential but the percentage of fines to (nominal grind sold) greatly affects wet out and ultimate (solids volume to liquid) ratios [if only as a function of total wetable surface area in that batch] and performance thereafter. Too many fines of any constituent may result in "dry" and friable matrix with varying performance across the part or batch of parts cast. A scientific and deliberate approach is advisable wherein you evaluate the fines percentage in the material purchased - and decide to do some separation from there and/or adjust liquid volume accordingly. Batch to batch variability is the challenge (we) will forever have to consider - across virtually all the constituents; unfortunately. Post-cure application of concentrated water glass is perhaps a more robust and reliable approach - but adding "some" water glass to the matrix (foamed or otherwise) is useful up to that terminal percentage. Again: I respect your interest and ingenuity and only hope that my comments are received in the spirit in which they are offered. From one coyote to another: thanks for sharing your experiments and results. Wiley Coyote (Ph.D in the school of hard knocks and other lessons in life)
Dirtpatchheaven and vc No. 1) Thank you both very much! VERY interesting VERY usable information THANK YOU for sharing this information and for making it real with your personal narrative. I would head, implore, beseech and pray others will AT THE VEEEEEERRRRY LEAST take this information into consideration! I wholeheartedly agree that it is a superior and ergo preferred method to utilize the "Water glass" as an additive or possibly even complete immersion of the refractory matrix secondary to the initial cure. Moreover I can not stress the importance of redundant backup systems (IE: ceramic wool etc.) around any type of roof, wood, or other possibly flammable material penetrations. I would also encourage all who would consider this or projects like it ESPECIALLY as an a primary or even supplemental source of heat for a place in which is intended to be inhabited notably during periods of sleep to incorporate both smoke and carbon monoxide detectors into part of the home safety plan. I believe it is also worth mentioning that if this is intended to be utilized as such it may require a permit, and or inspection. It may also conflict with your homeowner's insurance which could be utterly disastrous.
Do you have any opinion or insight about utilizing "Water glass" with perlite and plaster of paris as in an application of this type?: ruclips.net/video/uIRTcmR6sSk/видео.html obviously it should intrinsically not be AS dangerous as it should pose significantly less opportunity to of a house fire. However my question is more along the lines of violent rapid expansion at the point of failure. (IE: I wouldn't want this to eventually literally blow up in my face)
Thanks for the question. I have used of water glass, perlite and plaster of Paris in refractory applications; with ans without some Portland Cement in the mix. Overall my opinion is that it is an effective mixture within a certain temperature range and duty cycle. Assuming you have a safe design to start with, of course. Too many designs fail to consider the required minimum radius's of turns and/or the effects of changing diameter in a given section / cross section. Inappropriate designs cause hot spots that can age a relatively small area of your matrix much faster than the surrounding material. Differential aging is akin to your system having cancer or an infection. Ultimately the affected parts will have to be treated and/or surgically removed. The goal of a safe and cost effective system is attainable though some general rules of thumb should be observed. For one: increase wall thickness whenever you can and always around areas that include flues, bends, or other transitions in/of materials and/or gasses. Second: add some reinforcement to the matrix. "Cat Hair" (catalytic fines) available at most cement suppliers, or long chopped strand fiberglass, go a long way to resisting expansion and holding the mix together. Steel mesh or a wire reinforcement is also a good idea if you have the ability to place it in your pour accurately. The mesh must not contact the sides of your shape and be placed to resist the strongest opposing force in the shape being poured. (tension, compression, etc) If you cannot reinforce the system internally then your system must physically do so by other means. One experiment I tried was to use a layer of ceramic wool placed against the surface closest to the fired surface and back filling with matrix behind it. Results were good in terms of retained thermal mass and safety. The wool took most of the heat and was not subject to the thermal stress issues that just matrix (is) but there was no doubt some loss of thermal efficiency in terms of heat transfer from the inner hot steel surface to the matrix. Overall I would not recommend this approach to new builders. Use the wool for sure. Don't try sophisticated laminated sections unless you have the equipment and some practice. In closing I'd like to address your last part: the risk of explosion. Violent decomposition of the gasses in a cement/plaster/perlite or other matrix is unlikely if you take reasonable precautions in the construction phase. Most decomposition's are in the form of steam and experienced as a loud cracking noise attended by violent expansion, shifting of mass, sound and heat. The failure I attempted to address in prior posting was of the resulting unplanned migration of heat to the surface or other components. These may indeed (explode) depending on their nature. Think of the towel and can of hair spray neatly arranged on the nice warm pipe or bench and then add 1000 deg F in a small area that is ordinarily only warm. You get the idea. More likely, worry about a matrix failure allowing heat to migrate to the exterior of the (pipe) that then contacts a wall penetration that is not spaced properly and/or not protected with a secondary or tertiary layer of insulation throughout the penetration. Installing air collars alone without fire resistant material sheathing, glass or wool insulation, and/or fire stopping /intuminescent caulk or foam is fast but not very wise. But as to the inherent risk of explosion; it is steam/gas based fractures you must mitigate via using vibration, vacuum, surfactants, post cure drying cycles, intelligent design... and other factors. Good question though. Thanks.
Not sure I understand your comment; sorry. Steel(s) indeed melt in the range of 2500 deg/F; give or take a few hundred according to composition. BTU's are a measure of energy evolved out of a given mass/substance expressed in metric terms. (kilocalories per unit mass... etc.) Not sure I followed your next point though. Its been a while since I have reviewed the video but I "think" the author was attempting to compare a RMH to "other" methods of burning similar fuels. Stated as a hypothesis: RMH's are not more than (5 times) more efficient than other means of open combustion of (insert fuel type) when measured via the (insert method) at (insert location). I think the comment was directed at "efficiency" which is not entirely described by combustion or melting temperatures alone. In general, "efficiency" is a measure of (work) over the unit of time. In RMH the "work" is reduction to energy (BTU) via combustion in (air). The time base is a comparison of work over (minutes to boil a pot of water) or more precisely: to reduce a (cubic mass) of (fuel) to (state percentage of reduction) via induced combustion over time. Or more simply: the time it takes to decompose a few briquettes into heat/gases, and, the ability to harness that (energy) in a concise, controlled, focused manner to some useful purpose - like heating water. RMH's are indeed more efficient than open camp fires. Are they 5 x more efficient? That was what I think the author (said). So (can?) a given RMH can (boil water) in as little as 1/5 the time that a it takes other fires/stoves to do so ? I don't know but I think that was the claim the video implied. Do RMH's use fuel more efficiently? Absolutely. Are RMH's 5x more efficient than say an open propane stove? I don't know. But if you were to burn the same fuel in a range of stoves and measure how efficiently they either do "work" or convert fuel to its by products of combustion: rocket stoves (RS's) reduce fuel pretty fast/completely. RMH's do a pretty efficient job of harvesting (scavenging) waste heat from combustion gases and storing or transferring it slowly to the surrounding area. Whether a given design of stove or heater is 5x more efficient; 5.1 times... 4.7 times... or some other ratio per unit of measure (BTU) is a complex "system" but can be modeled or tested. Whether the upper limit is 5 times more "efficient" or something less does not matter so much as that (we) collectively work to move that line in the sand via our experiments and collaboration. To the extent that your question accomplishes that - I thank you. If I misunderstood your question please run it by me again and I will take another shot at it. Thanks.
Thinking about your question again, I neglected to address another risk that should be considered by us all. That is the additional risk of carbon compounds accumulating in the system for any reason. Specifically, as a function of failure in the matrix that may or may not be visible. While I prefer to use the matrix as a "filler" between (steel) conduits (stack pipe, sched 40 pipe, etc) as a matter of utility and safety. Not everyone does this and some use the thin steel (please never use Aluminum) flue pipe such as might be used to vent a dryer. Regardless of materials (eventually) corrosive gases exist in the system - even at rest, which condense and settle to the ultimate failure of the system (better metals take longer but ultimately all will fail given enough chemical/electrolytic insult and time) which may not be visible; even when video inspected. Returning to the question, and especially once either the matrix or the (liner) fails, you get both uneven heat distributions (hot spots) and turbulent flow of some magnitude. Carbon deposits typically accumulate whenever the system parameters are (un)favorable (poor combustion, low draft, high back pressure and a hosts of other reasons - which (may) be encouraged by matrix failure as well. Think separation of the matrix that results in a hot spot; that results in liner distortion or failure, which (may) result in carbon deposits due to uneven pressure/temp/rms of the surface/ etc... which may cause further uneven distribution of heat/pressure... and further deposits... The knee bone is connected to the shin bone... and so on. You get the idea. Bad tends to worse and carbon has properties unto itself that makes it accumulate (log scale) once it gets a hold/start. This affects draft, which affects performance, which affects combustion and the (puppy chases its tail) until the system has an undesirable accumulation of carbon compounds (which are themselves combustible). Why this pertains to your question is because the same incipient event (hot spot and/or other failure) "may" become a potential ignition source - which can devolve in rather fast and very hot events (a.k.a. stack fires). If you have ever seen one, the initial flash off can be either slow or quite dramatic, and quickly raise internal pressures and temperatures way beyond (design) parameters. Think black powder shotgun worst case. This causes joints to move or separate (assuming you get the fire out) and sometimes splitting of weak elements. So say that as a sentence, perhaps you could get "blown up" if a poorly designed or poorly maintained system is allowed to accumulate a substantial amount of carbon internally, and, a defective or (out of range) parameter is exceeded (like internal temperature) due to a hot spot flash over. Admittedly you have to work at it to get such a hazardous situation but the kicker remains that you may not know you have a matrix failure and may not be able to see the failure even if you are fortunate enough to be present when they happen. As with the knee bone model above, one failure leads to the next and in this case things can go from bad to catastrophic with (some) of the symptoms being hidden. So routine inspection, cleaning, monitoring, and objective evaluation of the complete system is more than just about efficiency. It can save your property and your life. Not to preach, but this is in part why mixtures, constituent quality, consistency, and other procedures are essential when mixing up, applying, inspecting, and maintaining matrix-based components. Particularly, when they do not have both sides lined with additional support (steel) and/or refractory materials, and, why they need to be inspected periodically with a pyrometer to establish a baseline operating range, and deviations from historical trend. I know that is a long way of saying something simple, but as is so often the case, your simply worded question is indeed both complex and important to everyone that attempts to build/operate these systems. Thanks again for the question.
interesting stuff folks. The term "Water Glass" is a euphemism and really isn't glass at all - but it is a version of soluble sand ie silicon dioxide. Sodium Silicate is a pretty useful concrete sealant I'll for your links on aircrete to see about your use of foams and stabilizers. You might consider using other metal oxides instead of portland SEE-ment (I couldn't resist :) )
I have a question about the aircreat panels .Just how big can they be made an how thick can they be made ? Are they strong enough for a structural load ? What is the insulation R-value ? I am planning a cabin build here in Alaska an looking at options
Can this mixture be used to repair or replace the fire brick in my work shop Quebec wood stove or does it have too much insulation value for a wood stove ?
You mentioned wanting to get more water glass into the aircrete. Have you tried using the powered form of sodium silicate in the Portland cement before making the aircrete?
Do you have to take meds to help you sleep at night? My mind runs all the time, just as it seems your does, and I have to take meds to help me settle down or I'll go for days without sleep.
Not so great. It blocked the heat from getting into the room while everything was heating up initially. We ended up removing all but about six inches at the bottom.
Hi Elizabeth Unfortunately Portland cement desintegrates @~ 550 degree C You could saturate the cement based riser with water dilluted waterglas (sodium silicate) When the cement desintegrates and looses it's structural integrety, the waterglas would keep the riser pipe in shape. A clay liner within above mentioned riser pipe is not a bad idea at all. I suggest you to mix the wet clay with perlite or charcoal or saw dust or expanded clay to reduce cracks. Important.. allow enough time for drying and curing.
Not much is out there about Potassium silicate. Would you consider making a video on "double water glass" (an equal parts mixture of potassium silicate and sodium silicate)?
so I love this. I do have one concern.. if you use the water glass and pearlite will it not fill all of the holes when it got hot and this deter the insulating properties?
Ideas for refractory brick for kiln. Fire brick clay i used ill see how it does, but need it weather proof i am disabled and cannot build a structure to cover our propane kiln
I’m still waiting on an answer back from you guys on yr site. I wrote you a few weeks ago . I’m wanting to buy one of yr foam machines to build our home . This fire proofing info is apt for us since our home is in Qld Australia in a fire zone. I’m wanting to build rolling fire walls on the perimeter of our inner landscape, so get back to me mate. Suzy.🙏🇦🇺 ps. I’m planning on making a rocket stove mass heater and outdoor rocket fire bath as well using yr recipes and methodology.
Wow ! Impressive numbers on the heat. Mine only seems to max out at 300°F to 400°F or so.and is not the same mix no perlite or water glass in it...I am sure that must make a big difference running the rocket mass heater. Wulfy
@@priestesslucy no. Actually it does quite well. Have a new one I built with fire brick and it performs great- still not super hot though, but no spot and it lights up and rockets like a charm!
@@wulfclaw4921 Ohhhhhh, I thought you were doing the Heat Riser measurements (which I don't know how they take them, but yeah the internal heat riser temps get nuts.) Top of the barrel that sounds about right ^~^
I have an idea for this to be modified to make fireplaces more efficient and effective for heat and cooking, especially when power is down. I believe it will work. I haven't seen it done yet. Maybe I can get the chance to draw it and send it to u to have at it since I cannot build it right now. I think you will change the fireplace world! LOL
Hi there! Hey sobi have pondered "rocket mass heaters" for years.. and I am at place where I can begin work on my third project and this go around I am wanting to "break new ground" in the ascetic/artistic design of the rocket mass heater, on a permanent install. On this build I will be using 30 year old pieces of glass that have the appearance of corrugated metal. The pieces are about ⅝ thick. In my thought process I figured that I would need to make "my own" refractory cement and thats how I found your excellent videos. I would like to share with you my overall design and concepts if you would be willing to share your thoughts on how my design could be better and what I might need to do to improve its long term functionality.
I I'd like to make say a 12" long road maybe 5 inches in diameter drill a 1" = 1 1/2 " hole.. and coat it in your water glass solution. I want to make a rocket chinmey for an wick oil heater...
I just bought your plans for the foam maker. do you think that the rocket stove pipes in the thermal mass sofa system can be adaapted to run though metal pipes buried in screed so that you have an underfloor heated slab?
This is my video instead of Darwin's. He made the stove and the plans over on Honey Do Carpenter. I just test the stove for him. That being said, maybe. We have dropped the pipe twenty four inches without losing momentum of the smoke. Dropping it further into the floor we haven't tried yet. But it's a great idea!
@@dirtpatcheaven thanks. I am planning to run standard underfloor heating water pipes in my dome build floor and heat the water with a central rocket stove, and have a diverter in the chimney to either heat the water or the thermal mass bench. the stove would not be very far up from the floor pipes, its usuaal to bury the pipes in about 3 inches of screed and have tiles laid over, so I wondered about doing away with the heated bench and using the floor as the thermal mass store instead
I really like these folks. I get to visually experiment without buying a thing. bless the makers!
You are one lucky guy to have a wife who shares your enthusiasm, innovation and creativity ♥️
I was thinking the same thing !
@@carpenterfamily6198
My wife is the exact opposite.... Except when it's a project for her...
Agreed. I almost hate him for that. 😅🤷
I've been trying for years to get my husband interested in my rocket stove project, Doh.
If you put aluminum powder into a mix with water glass. The high base environment will produce hydrogen that will foam up and make an aircrete like material. The hydrogen will escape from the material soon after leaving a safe fire proof foam. But your max temp with waterglass will be around 2200F
By adding a male lip on one end and female groove on opposite end, units can be assembled or stacked.
Darwin brought me here...he's genius and super humble! Aircrete is amazing! Thanks for sharing!
Into Evans uses pearlite mixed with a small amount slurry of bentonite to make an insulated castable for the riser. Using the waterglass and dry bentonite might just be an improvement.
I so wish that those who help with low income folk like myself and my husband, we're both disabled but we could manage a wood stove like this, could install something like this in our homes rather than throw money to oil companies, to electric companies...it would be such a blessing!
We installed a "regular" wood burning cook stove, and it is a real blessing. It saves on propane and electric expenses, but it is a lot of work.
Answersfromgod.com/?youtube=NcVlb-z6Y94
Just for the record the water glass is reacting with carbon dioxide heat just speeds up the reaction. The crust you see is silicon dioxide and sodium carbonate.
Try a vacuum chamber to get the waterglass deep in the aircrete/perlite. Should work. It works with Epoxy resin and cactus Juice in wood.
The main purpose of a rocket mass heater is to transmit as much heat from the burning into the mass - allowing for that heat to migrate into living space. Theoretically, you want the smoke ultimately leaving the chimney to the outdoors to be cool. Aircrete, perlitecrete and other kinds of air entraining methods will act as an insulator, not as a reservoir for heat - meaning you'll end up losing most of your heat out the chimney.
You can buy bags of refractory cement, but the most cost effective method I've used is adding a good shovelful of fire clay to each 80 lb bag of ready mix concrete. Or, if you are laying in stones, you add the fire clay to a similar weight of mortar mix. I've built a pizza oven and I can assure you that thing gets hot. I've had no degrading of any portland cement product I've used.
If this is working right it will get way to hot for normal cement. Cement disintegrates at about 1000 F The riser in the stove can reach 1900. Nearly double the 1000 degrees of a pizza oven.
@@ghz24 ... Yes in part. I have a steel angle iron in my brick oven that deformed slightly in the heat. I take this to mean the top of the pizza oven reached close to 1900F.
Still, even with that heat, the portland/clay mortar joints between the oven's red clay bricks have not been affected. Disintegration certainly has not happened.
By comparison then, for a rocket mass heater, a well designed, heat resistant firebox is necessary, but adding clay to concrete mix for the mass - often benches - will be adequate to sustain the high temperatures
Good stuff. I was looking into how I could use aircrete in a rocket mass heater and here it is. Made the foam generator got some decent aircrete now on the the water glass. I was thinking starlite or the glue baking soda cornstarch mix might also be an option.
Suggestion procedure: You might pre=make sections of aircrete riser with groove on top ide and lip on bottom to interlock. Then take cured unit drop in tank of water glass solution to coat all surfaces. Then coat with Portland cement and stack up sections and finish bonding water glass with fire.. Then determine temperature and cooking time to finished product.
Wow! You guys are answering questions I hadn't even gotten to yet. Thank you so much for making these videos.
(I absolutely subscribed!)
I just watched the story on you two and I am so HAPPY for you. God Bless You!❤
Where did you watch it ?
sodium silicate reacts with the calcium compounds in concrete to form calcium silicate, which has a melting point of 2500+ degrees F.
Try adding some graphene to the silicate mix. Expensive but impressive results. Other components work to boost refractory performance as well.
Totally, ABSOLUTELY, *FASCINATING* !! I swear I could see the wheels turning in your head!
Rocket heaters can easily be made lightweight and portable. Rocket mass heaters, as the name implies, can not. Once you remove the mass from a rocket mass heater, it becomes a simple rocket heater. Conversely, a rocket mass heater is simply a rocket heater with a massive thermal battery attached to it to store excess heat.
I didn't write this to put you down. I just want to highlight the differences between rocket heaters and rocket mass heaters. You built an awesome rocket heater. Without the thermal battery, it is not a rocket mass heater. I do like the creativity in using aircrete for the insulated riser. This is an important part of making an efficient rocket heater.
Have you given any thought to possibly installing the actual burn chamber of the rocket heater outdoors? The children could be inside while the high heat fire would be outside and away from the small structure. You could route the flu chamber to wind inside of the cabin to produce heat with the threat of a ultra hot fire on the outside.
If you were to put that glass with the aircrete in a vacuum environment and then alternate between vacuum and refreshing you could probably get the absorption rate way up there
You can buy fire brick cement mix. Its about $80 per bag
Exactly.. 5bags later and materials plus time... might as well buy a 4500 efficent rated stove
@@vanderumd11 but where's the fun in that? ..not to mention, 5 bags for 1 rocket stove? Will you be flying it to the moon? Considering the mix, I was thinking maybe ½ a bag would make a nice sized rocket stove..
I've been doing something similar before seeing this. Seems to be the right path.
I am glad your HVAC system is more to your liking. This does not mean that your wood produces more energy than your neighbor's. Your system EXTRACTS more energy from your stove in the manner you have designed it. Your residence is probably better insulated and your comfort level may also be different than others. Some have poor insulation, others might feel that a temperature of 78 degrees is what makes them feel comfortable. You extract more from a chord of wood by heating solid masses than someone else's heating system that utilizes a fireplace for heating their living space. It all has to do with the degree of insulation of the living space and the method of extraction of heat from the fuel(wood) that is burned and COMFORT LEVEL for different people. I noticed you looked comfortable inside your house dressed in your overcoat. Someone else might feel more comfortable being in a t-shirt while indoors. Your comfort level is obviously different. Someone else might prefer more humidity in his indoor space than you do. Insulate your house better and extract heat more efficiently from your fuel within the parameters of your comfort zone.
Thanks for publishing this info! Refractory mixes are not hard to find, but I hadn't considered the weight. I just assumed I'd have to put up with a terribly heavy set-up. Thanksfully, I found this before I was about to start on my own.
You are welcome!
The thing is, you won't have to let the fire burn into the night, you can time the burn to end before you want to get to bed, the bench will keep your kids from freezing.
Once, I saw a guy turn paper pulp into a fireproof & waterproof casting.
Plaster of Paris, & SodiumSilicate,...
or Gypsum.
You should take advantage of the size of your segments! Use a vacuum chamber and submerge your riser segment for permeation. You'll be able to use a more concentrated mix of sodium silicate and slow cure it. I'd bet that your overall product would be a lot closer to what you want.
Could you elaborate for a dumb blonde trying to understand?
@@priestesslucy which part?
Great idea - THANKS! Really, really helpful.
By the way, yes the heat blasts off the water but it's the CO2 gas from the combustion process that does the curing of the water glass (from torch combustion, or gas (not electric) oven, or just use dry ice from the local welding supply - you get it). Air curing to glass is pretty slow only because ordinary outdoor air is only about 0.04% CO2. That is, it is not the heat that makes the solution into glass. Most off the shelf water glass solution is about 40% silicate in suspension and the rest is in fact water, so the expansion to the perlite-like appearance is caused by steam escaping from the heated water only. But who cares - the end results are perfect! Thanks again!
have you ever done a pressure test on aircrete like you use to do on the bridge concrete?..i guess what i am getting at is...have you come up with a load bearing mix for building structure walls in homes, etc.?
Darwin...You Are A GENIUS! Wow...I'm so impressed! So glad I found you thru Julie. xo
I built 6 rocket mass heaters (rebuilt it 6 times) in a dome I had over two winters in Wisconsin. I learned a great deal about them and how they fail. If a riser has a catastrophic failure, it can drop materials into the burn chamber and the active flame comes out the inlet of the RMH. It happened to me and luckily I was sitting here there and I had plenty of water from my aquaponics system to extinguish the flame. I absolutely love RMHer's. I was able to heat my 20' dome that only had two layers of 6mil plastic to 75 degrees each night. As I remember the coldest night was -23 degrees F. And, the most wood I ever used in a night was 3 paper grocery bags of pallet wood. Nothing better than cherry tomatoes in late January in Wisconsin! I miss my dome!
“If a riser has a catastrophic failure, it can drop materials into the burn chamber and the active flame comes out the inlet of the RMH. It happened to me and luckily I was sitting here there and I had plenty of water from my aquaponics system to extinguish the flame.”
And this is the problem. The idea is awesome. But Paul Wheaton doesn’t seem willing to admit the flaws. You cannot get insurance on your house for this reason. Codes will not allow the RMH for this reason. They are being built by AMATEURS which is fine, but there is no accepted design parameters, no UL testing. It’s an awesome thing, until it isn’t.
Awesome! Can you give a good refractory recipe? I see none here.
@@brucea550 these things are slowly changing thankfully.
There are stoves getting approval that can be run through a mass.
The legal one I know right now is like $2500, which is a lot. But if you have an expensive home it's worth it to get insured
@@priestesslucy
I’m not sure what you mean about stoves that can be run through a mass. The system has to be designed as a system, not a factory woodstove and a home built mass. Could you maybe mention a source for what you know of? I do know there are companies making the actual prefab riser that you can buy for your RMH fabrication, but still not a complete UL system that will satisfy codes or insurance underwriters. I’d LOVE to find one!
Paul W. makes ‘I know of a guy’ comments but never any actual facts or sources.
Even if you have a non-expensive home, having homeowners insurance provides you with liability protection if, for example, someone gets hurt on your property. It’s not just about ‘if the house catches fire’. All these uninsured folks are living on ‘a wing and a prayer’, and their only protection from potentially getting sued is their own poverty- can’t get blood from a turnip. It’s also highly irresponsible putting these experimental heaters in occupied spaces where people sleep.
Please don’t misunderstand, I think experimental stuff is great, and I have now built an RMH in a detached garage, with the firebox separated from the rest of the structure by a concrete wall. So far I like it. But it’s clearly experimental, and I wouldn’t put one in my house.
@@brucea550 Liberator is the one I know that's available and legal now.
I have heard that the Romans used Volcanic Ash as a cement and some of it is as good today as the day they mixed it.
My husband told me that and I didn't believe him. Had to go look it up, but you are right!
@@dirtpatcheaven We could have roads and driveways that would last forever if we used it today.
Amazing ingenuity!
An old "recipe"for build walls with refractory bricks,is a mix of ashes and portland cement.Maybe that mixture results a even better special heat resistant air crete.
By adding a male lip on one end and female groove other end, units can be stacked for a chimney.
The piece you burnt in your hand what was it made of... cement and pearlite?
Do you have a link to the 'water glass'...? What a cool video.!! Thank you for sharing...!
Hi Julie and Darwin- I watch both your channels avidly. -Im living a similar life down in NZ. Why Im here is to ask If I might pay homage to you two and show some snips of this video? to introduce you and show how im making my reaction chamber insulation for my plastic depolymerisation machine- turning waste plastic into diesel fuel
You are going through more work than you have to,I am a ticketed refractory bricklayer,and have been relinning lime kilns,power and recovery boilers,furnaces etc for 20 years.all you need is a bag of lightweight castable.ther is no abrasion so a llightweight castable should work no problem and a bag should only cost you 20 30 bucks,we use it by the pallet and b train.
Where can I find this $20 a bag lightweight refractory
What would be a good cheap mix for a forge? I was told sand and plaster. But that seems to simple and i heard it fails after a couple uses.
not sure if you check the comments mate but it might be useful to try vacuum impregnation similar to how you use a vacuum to get epoxy into fibreglass or carbon fibre.
I’ve heard some people coat refractory materials with Satanite - which would be the best coating, Water Glass or Satanite ?
It's a shame that they stopped using the shuttle you could have made cheaper tiles on the bottom for re-entry and probably better. Well done professor honey do carpenter
You absolutely need to get a patent on that! NOW before you talk about it too much.
Julie you are a good friend :)
SKPChick 31 YES, I AGREE! HE SHOULD PATENT IT RIGHT AWAY! !!!
SKPChick 31 provisional is easy and gives time to make a full patent
Well, I thank him for thinking in the future and sharing for free. Our world is moving in a new direction, freeing us with technology... you may want to look into blockchain technology, it is the way of the future for contracts of all kind$.
they invented a plastic in the eighties that could take an acytiline torch they could have dipped the entire shuttles into they didnt award the contract to the man and ruined his life
Getting a patent is easy. Showing that your admixture remains stable over time and does not fall apart is a different thing. Building new system might be easy for some. Building something that lasts and does not show material defect with the passage of time is a different thing. As the saying goes in the advertising business: "-Charlie, we don't want a tuna with good taste; we want a tuna that tastes good!"
-48 a few days ago with more to come, a bit tired of those $250 a month natural gas bills. I've had many wood stoves over the years, many bought and built. The one thing I've learned is burning green wood is when creosote can become a problem. So as long as you don't burn green wood you hopefully won't that problem. ( However in a wood stove, 3 dry logs and 2 green logs makes for a fire that isn't as hot. )
We burn really dry wood but it is soft wood. We only grow soft wood in our area, pine and douglas fir. We had creosote buildup every six weeks in our conventional wood cook stove. The new rocket stove hasn't had any creosote with the same wood now that we have the aircrete chimney on it for insulation.
@@dirtpatcheaven Have you tried burning pallet wood? I picked up 250 free pallets, many are built with hardwood, these burn very very "HOT" so doesn't take a whole bunch to warm the double garage up. I usually run a skill saw, inside the stringers on each side, of the pallet, then only have the middle nails to deal with. I honestly believe you're mass heater should have been about 1/2 the size, as big as it is, as you live in a tiny house. ( It would also take up less space. "It must get horribly "HOT" up-top/ in the loft, as hot air rises. "Just my thinking" I find the problem with wood burning is it is incredibly hard to control temperatures. There is another style of wood heating system I tried and really liked, however when it went below -10, it couldn't keep the place warm even when burning massive amounts of wood. Check this out; --ruclips.net/video/v_i5Cj2LSUo-/видео.html- - I'm sure you're buddy could rig one of these up for you, the thing literally functions like a natural gas furnace, with a thermostatic heat controlled fan. I built one, just to test, and really really liked it, but because it gets so cold here, it would have burned to much wood, to be efficient.- ruclips.net/video/2mZM74qPVrM/видео.html
Might try fumed silica in place of Portland 2, or bentonite.
You are the Honey "Can" Do Carpenter! 😁
Love you Darwin!!! Genius!
What is needed here is a list of places where a person can buy these ingredients at a low cost.
Excellent stuff bro
you need not heat water glass to harden it. it hardens due to co2 absorption. it hardens with your torch because combustion causes co2 to be created. it will harden on its own with time as it gets it co2 from the air or you can force it in seconds with co2 gas injection from a tank and it will not expand like it does when you head it. I use it for making sand casting cores for molten metal. I'm going to try just perlite wetted lightly with with water glass the rammed in a form and injected with co2.
Kilns and pottery wheels are needed, butnat times well most cant afford....i am one so we want to grow our craft and way of using pottery for our needs. Itll keep us busy to fire our grandsons projects easily
Ahaa....he guy.you and family are great...love you all.
Keep wondering what the waterglass is cut with-- is it water? 50/50 mix... with what?
There is a major oversight I will attempt to explain. Any and all materials have a couple of important properties as they pertain to RMH's . One is thermal storage capacities known as "K" value and the other is insulation value known as "R" value. The two properties are inverse to each other meaning if it is a good insulator its a terrible heat storage material or to say it another way would be the more R then the less K or the more K the less R. being that RMH work with principal of heat storage. Making a RMH out of foam aircrete will greatly reduce the very principal RMH are built on and that is heat storage. Thermal capacity material charts are available on line to view. water is the unit of measure for K value and water is 1k value stone is .2 thus water holds 5 times more heat than stone pound for pound but stone is more dense ( water is 63 pounds per cubic foot while stone is 95) thus by area water stores 3.26 more heat than solid stone (not gravel or rocks with spaces). concrete is equal to solid stone in heat capacity for storage but when you add the air bubbles the insulation value of the concrete goes way up and the ability to store heat known as K value goes way down defeating the main functioning principal of the RMH , any questions?
Van Powell Right. No good for mass but good for the riser. Time will tell.
So good application for the hot flue gas insulating components but bad idea in the thermal transfer sections... Makes a better cast insulating ring / penetration assy for the flue pipe though, assuming the physicals are there or can be boosted with glass/ceramic/wire or whatever. Good explanation. Thanks.
v c To simplify it: Combustion areas, or places you don't want to get hot.
Good points Van Powell. Ideally though a good system utilizes insulators in the right key points to also protect system componets from premature failure while it maximizes the burn, transfers, then captures, stores and then releases the heat in as efficent a manner to conserve the resources. Combustion of all materials and gasses, transfer of heat to a temporary storage medium, then as slow as possible a release of heat from the storage medium all with a goal of safety in mind. Safe, light, and cheap Insulators in the right points of such a system is a goal for many an RV and Tiny Home building hobbiest such as myself. So this option looks promising and worth some experimentation for those of us knowledgeable and cautious adults. Used as a thinner layer outside a metal flue instead of as the flue or maybe even adding some steel tubeing to the inner surface partually within the mold to store and funnel the hit gases while protecting outer surfaces.
new skool/old skool:
now we understand and agree/see cleaner burns with highet draft created only by higher temperatures in primary and secondary burn chambers, created only by insulation (not resistance). With higher draft and less smoke, we can build bigger and longer resistance channels after the burn chamber before venting outside. Again, ANY resistance/induction of the primary and secondary burns creates more smoke and residue and slows the draw/output of air, eats more wood per calorie output. Seems counter-intuitive at first, but it is how it is at this point, sorry about your 30+ years' experience. We knew it thousands of years ago and are only realizing it again. My advice to 'experts:" stay more interested in your topic than your being right
Howdy. I respect what you are doing but would like to comment on something I think I heard you say in re adding water glass (silicate) to the original matrix - as opposed to applying it post-cure by immersion or cement / silicate application afterwards. I offer the following from hard experience that too high a concentration of water glass in the original matrix (may) ultimately expand - as it appears to in your surface ablation demonstration - and cause failures (cracking) over time. From my observation, differential internal stress(es) cause expansion in the cure(ing) matrix - which goes on for (months) - across heating/cooling cycles normal to your intended use as a (flue pipe).
Stated another way, your insulation value is preserved until essentially mechanical stress in the matrix causes failure - at which point you get a hot failure which you may not even notice unless you are present to hear the crack. (My) first symptom was the sudden development of a vertical hot spot which translated to the exterior (steel) form and began to heat radically. Fortunately, I was awake and heard/felt the temperature change in the system and smelled the paint over heating. More fortunately the failure did not occur near the roof penetration. Diagnosing it required disassembly and destruction though - whereupon the material looked quite normal on either side of the vertical crack. The remaining material was still quite functional and without signs of soot, carbon, decomposition, chalking or other chemical failure (per se) and did not exhibit voids that might have indicated an air inclusion or water pocket (i.e. steam fracture). The cross section was to spec and not appreciably thinner in the failure area. The matrix had simply mechanically failed and permitted heat migration to an area that was not acceptable.
In all, the remedy was simple as I had likewise taken a modular approach to the design. I was fortunate to have cast more sections than I needed and simply swapped the failed section out. It has not failed since though I encourage others to really think ahead about mechanical issues and not build complex designs without really thinking through issues that may induce a lot of variability across thermal stress internal to the (pipe) - such as in way of bends and long pipe runs, or where back pressure(wind) or sudden cooling via rain runoff and condensation may work against you over time. Milled or chopped glass fiber can mitigate stress failures but need to be carefully dispersed in the matrix to avoid balling and inconsistencies. Shorter fiber lengths "flow" better when pouring/forming your shape.
It is strong argument however for using ceramic wool (not just fiberglass building insulation) and an air gap in all wall and roof penetrations though to provide an extra layer of safety despite how well your matrix performs. Likewise - folks need to use all-steel forms (no aluminum - ever), as i know you have shown in your videos. Thin wall dryer ducting is a poor compromise to heavier gauge wood stove piping. All welded sleeved or flanged construction is safer yet and lasts longer (at the compromise of weight of course).
Otherwise to the topic, I have found that box-store grade perlite, vermiculite, and even sawdust shavings and other materials can contain widely variable percentages of "fines" that (can) affect the quality of your matrix. Some fines are essential but the percentage of fines to (nominal grind sold) greatly affects wet out and ultimate (solids volume to liquid) ratios [if only as a function of total wetable surface area in that batch] and performance thereafter. Too many fines of any constituent may result in "dry" and friable matrix with varying performance across the part or batch of parts cast. A scientific and deliberate approach is advisable wherein you evaluate the fines percentage in the material purchased - and decide to do some separation from there and/or adjust liquid volume accordingly. Batch to batch variability is the challenge (we) will forever have to consider - across virtually all the constituents; unfortunately.
Post-cure application of concentrated water glass is perhaps a more robust and reliable approach - but adding "some" water glass to the matrix (foamed or otherwise) is useful up to that terminal percentage.
Again: I respect your interest and ingenuity and only hope that my comments are received in the spirit in which they are offered. From one coyote to another: thanks for sharing your experiments and results.
Wiley Coyote
(Ph.D in the school of hard knocks and other lessons in life)
Dirtpatchheaven and vc
No. 1) Thank you both very much!
VERY interesting VERY usable information THANK YOU for sharing this information and for making it real with your personal narrative. I would head, implore, beseech and pray others will AT THE VEEEEEERRRRY LEAST take this information into consideration! I wholeheartedly agree that it is a superior and ergo preferred method to utilize the "Water glass" as an additive or possibly even complete immersion of the refractory matrix secondary to the initial cure.
Moreover I can not stress the importance of redundant backup systems (IE: ceramic wool etc.) around any type of roof, wood, or other possibly flammable material penetrations. I would also encourage all who would consider this or projects like it ESPECIALLY as an a primary or even supplemental source of heat for a place in which is intended to be inhabited notably during periods of sleep to incorporate both smoke and carbon monoxide detectors into part of the home safety plan.
I believe it is also worth mentioning that if this is intended to be utilized as such it may require a permit, and or inspection. It may also conflict with your homeowner's insurance which could be utterly disastrous.
Do you have any opinion or insight about utilizing "Water glass" with perlite and plaster of paris as in an application of this type?:
ruclips.net/video/uIRTcmR6sSk/видео.html
obviously it should intrinsically not be AS dangerous as it should pose significantly less opportunity to of a house fire. However my question is more along the lines of violent rapid expansion at the point of failure. (IE: I wouldn't want this to eventually literally blow up in my face)
Thanks for the question. I have used of water glass, perlite and plaster of Paris in refractory applications; with ans without some Portland Cement in the mix. Overall my opinion is that it is an effective mixture within a certain temperature range and duty cycle. Assuming you have a safe design to start with, of course. Too many designs fail to consider the required minimum radius's of turns and/or the effects of changing diameter in a given section / cross section. Inappropriate designs cause hot spots that can age a relatively small area of your matrix much faster than the surrounding material. Differential aging is akin to your system having cancer or an infection. Ultimately the affected parts will have to be treated and/or surgically removed. The goal of a safe and cost effective system is attainable though some general rules of thumb should be observed. For one: increase wall thickness whenever you can and always around areas that include flues, bends, or other transitions in/of materials and/or gasses. Second: add some reinforcement to the matrix. "Cat Hair" (catalytic fines) available at most cement suppliers, or long chopped strand fiberglass, go a long way to resisting expansion and holding the mix together. Steel mesh or a wire reinforcement is also a good idea if you have the ability to place it in your pour accurately. The mesh must not contact the sides of your shape and be placed to resist the strongest opposing force in the shape being poured. (tension, compression, etc) If you cannot reinforce the system internally then your system must physically do so by other means. One experiment I tried was to use a layer of ceramic wool placed against the surface closest to the fired surface and back filling with matrix behind it. Results were good in terms of retained thermal mass and safety. The wool took most of the heat and was not subject to the thermal stress issues that just matrix (is) but there was no doubt some loss of thermal efficiency in terms of heat transfer from the inner hot steel surface to the matrix. Overall I would not recommend this approach to new builders. Use the wool for sure. Don't try sophisticated laminated sections unless you have the equipment and some practice. In closing I'd like to address your last part: the risk of explosion. Violent decomposition of the gasses in a cement/plaster/perlite or other matrix is unlikely if you take reasonable precautions in the construction phase. Most decomposition's are in the form of steam and experienced as a loud cracking noise attended by violent expansion, shifting of mass, sound and heat. The failure I attempted to address in prior posting was of the resulting unplanned migration of heat to the surface or other components. These may indeed (explode) depending on their nature. Think of the towel and can of hair spray neatly arranged on the nice warm pipe or bench and then add 1000 deg F in a small area that is ordinarily only warm. You get the idea. More likely, worry about a matrix failure allowing heat to migrate to the exterior of the (pipe) that then contacts a wall penetration that is not spaced properly and/or not protected with a secondary or tertiary layer of insulation throughout the penetration. Installing air collars alone without fire resistant material sheathing, glass or wool insulation, and/or fire stopping /intuminescent caulk or foam is fast but not very wise. But as to the inherent risk of explosion; it is steam/gas based fractures you must mitigate via using vibration, vacuum, surfactants, post cure drying cycles, intelligent design... and other factors. Good question though. Thanks.
Not sure I understand your comment; sorry. Steel(s) indeed melt in the range of 2500 deg/F; give or take a few hundred according to composition. BTU's are a measure of energy evolved out of a given mass/substance expressed in metric terms. (kilocalories per unit mass... etc.) Not sure I followed your next point though. Its been a while since I have reviewed the video but I "think" the author was attempting to compare a RMH to "other" methods of burning similar fuels. Stated as a hypothesis: RMH's are not more than (5 times) more efficient than other means of open combustion of (insert fuel type) when measured via the (insert method) at (insert location). I think the comment was directed at "efficiency" which is not entirely described by combustion or melting temperatures alone. In general, "efficiency" is a measure of (work) over the unit of time. In RMH the "work" is reduction to energy (BTU) via combustion in (air). The time base is a comparison of work over (minutes to boil a pot of water) or more precisely: to reduce a (cubic mass) of (fuel) to (state percentage of reduction) via induced combustion over time. Or more simply: the time it takes to decompose a few briquettes into heat/gases, and, the ability to harness that (energy) in a concise, controlled, focused manner to some useful purpose - like heating water. RMH's are indeed more efficient than open camp fires. Are they 5 x more efficient? That was what I think the author (said). So (can?) a given RMH can (boil water) in as little as 1/5 the time that a it takes other fires/stoves to do so ? I don't know but I think that was the claim the video implied. Do RMH's use fuel more efficiently? Absolutely. Are RMH's 5x more efficient than say an open propane stove? I don't know. But if you were to burn the same fuel in a range of stoves and measure how efficiently they either do "work" or convert fuel to its by products of combustion: rocket stoves (RS's) reduce fuel pretty fast/completely. RMH's do a pretty efficient job of harvesting (scavenging) waste heat from combustion gases and storing or transferring it slowly to the surrounding area. Whether a given design of stove or heater is 5x more efficient; 5.1 times... 4.7 times... or some other ratio per unit of measure (BTU) is a complex "system" but can be modeled or tested. Whether the upper limit is 5 times more "efficient" or something less does not matter so much as that (we) collectively work to move that line in the sand via our experiments and collaboration. To the extent that your question accomplishes that - I thank you. If I misunderstood your question please run it by me again and I will take another shot at it. Thanks.
Thinking about your question again, I neglected to address another risk that should be considered by us all. That is the additional risk of carbon compounds accumulating in the system for any reason. Specifically, as a function of failure in the matrix that may or may not be visible. While I prefer to use the matrix as a "filler" between (steel) conduits (stack pipe, sched 40 pipe, etc) as a matter of utility and safety. Not everyone does this and some use the thin steel (please never use Aluminum) flue pipe such as might be used to vent a dryer. Regardless of materials (eventually) corrosive gases exist in the system - even at rest, which condense and settle to the ultimate failure of the system (better metals take longer but ultimately all will fail given enough chemical/electrolytic insult and time) which may not be visible; even when video inspected. Returning to the question, and especially once either the matrix or the (liner) fails, you get both uneven heat distributions (hot spots) and turbulent flow of some magnitude. Carbon deposits typically accumulate whenever the system parameters are (un)favorable (poor combustion, low draft, high back pressure and a hosts of other reasons - which (may) be encouraged by matrix failure as well. Think separation of the matrix that results in a hot spot; that results in liner distortion or failure, which (may) result in carbon deposits due to uneven pressure/temp/rms of the surface/ etc... which may cause further uneven distribution of heat/pressure... and further deposits... The knee bone is connected to the shin bone... and so on. You get the idea. Bad tends to worse and carbon has properties unto itself that makes it accumulate (log scale) once it gets a hold/start. This affects draft, which affects performance, which affects combustion and the (puppy chases its tail) until the system has an undesirable accumulation of carbon compounds (which are themselves combustible). Why this pertains to your question is because the same incipient event (hot spot and/or other failure) "may" become a potential ignition source - which can devolve in rather fast and very hot events (a.k.a. stack fires). If you have ever seen one, the initial flash off can be either slow or quite dramatic, and quickly raise internal pressures and temperatures way beyond (design) parameters. Think black powder shotgun worst case. This causes joints to move or separate (assuming you get the fire out) and sometimes splitting of weak elements. So say that as a sentence, perhaps you could get "blown up" if a poorly designed or poorly maintained system is allowed to accumulate a substantial amount of carbon internally, and, a defective or (out of range) parameter is exceeded (like internal temperature) due to a hot spot flash over. Admittedly you have to work at it to get such a hazardous situation but the kicker remains that you may not know you have a matrix failure and may not be able to see the failure even if you are fortunate enough to be present when they happen. As with the knee bone model above, one failure leads to the next and in this case things can go from bad to catastrophic with (some) of the symptoms being hidden. So routine inspection, cleaning, monitoring, and objective evaluation of the complete system is more than just about efficiency. It can save your property and your life. Not to preach, but this is in part why mixtures, constituent quality, consistency, and other procedures are essential when mixing up, applying, inspecting, and maintaining matrix-based components. Particularly, when they do not have both sides lined with additional support (steel) and/or refractory materials, and, why they need to be inspected periodically with a pyrometer to establish a baseline operating range, and deviations from historical trend. I know that is a long way of saying something simple, but as is so often the case, your simply worded question is indeed both complex and important to everyone that attempts to build/operate these systems. Thanks again for the question.
interesting stuff folks. The term "Water Glass" is a euphemism and really isn't glass at all - but it is a version of soluble sand ie silicon dioxide. Sodium Silicate is a pretty useful concrete sealant I'll for your links on aircrete to see about your use of foams and stabilizers. You might consider using other metal oxides instead of portland SEE-ment (I couldn't resist :) )
no. portland can't handle the heat. I have used water glass sand clay and perlite. worked very well.
What is the final perlit air-crete formula?
Did you get the answer?
@@randalmoroski4423 I paid him for the formula
Omg really? What did he charge you, if I might ask?
@@johnparker-tn1os don’t remember, it is in his Etsy sight.
I have a question about the aircreat panels .Just how big can they be made an how thick can they be made ? Are they strong enough for a structural load ? What is the insulation R-value ? I am planning a cabin build here in Alaska an looking at options
Try diluting thenwater glass less, still with water but like 75% liquid glass rest 25% water
Why don't you use the dilute water glass to wet the cement before mixing in the foam to make the aircrete in the first place.
Yes! In principle you are right.
The Problem is the extrem short "pot life". Waterglas reacts instantly.
thats soooo amazing!!! Thanks for sharing!!
Where do I buy water glass
Thank you for sharing!
Can this mixture be used to repair or replace the fire brick in my work shop Quebec wood stove or does it have too much insulation value for a wood stove ?
You mentioned wanting to get more water glass into the aircrete. Have you tried using the powered form of sodium silicate in the Portland cement before making the aircrete?
Do you have to take meds to help you sleep at night? My mind runs all the time, just as it seems your does, and I have to take meds to help me settle down or I'll go for days without sleep.
Rather than using only Portland cement, use layers, outside Portland with an inner liner of fire clay.
Looking forward to a final aircrete refractory mix recipe.
so what if you did add some clay...even better?
how did the pebble fill around the barrel work?
Not so great. It blocked the heat from getting into the room while everything was heating up initially. We ended up removing all but about six inches at the bottom.
what about a clay flue liner for the burn chamber and riser and aircrete around it
Hi Elizabeth
Unfortunately Portland cement desintegrates @~ 550 degree C
You could saturate the cement based riser with water dilluted waterglas (sodium silicate)
When the cement desintegrates and looses it's structural integrety, the waterglas would keep the riser pipe in shape.
A clay liner within above mentioned riser pipe is not a bad idea at all.
I suggest you to mix the wet clay with perlite or charcoal or saw dust or expanded clay to reduce cracks.
Important.. allow enough time for drying and curing.
For harden waterglass you should use just CO2 gas enstead of heat.
Not much is out there about Potassium silicate. Would you consider making a video on "double water glass" (an equal parts mixture of potassium silicate and sodium silicate)?
Darwin hasn't made videos for a while....he is the guy for that stuff. I just had a laboratory off grid cabin for him to try his experiments out on.
You might making a product for high temperature boilers for the refractory in the cells but it needs to be strong also
Do you know if the foaming agent is safe and not hazardous ??? Thanks
Have you tried mixing the water glass with the foamcrete? If so what was the results?
Have you tried mixing undiluted water glass in your slurry instead of the foam?
so I love this. I do have one concern.. if you use the water glass and pearlite will it not fill all of the holes when it got hot and this deter the insulating properties?
Ideas for refractory brick for kiln. Fire brick clay i used ill see how it does, but need it weather proof i am disabled and cannot build a structure to cover our propane kiln
hemen beğendim. emek var. bilgi var.
Why not use the Roman concrete mix they used to build the dome in Rome that’s been standing 2,000 years? They used volcanic ash in it.
02:04: What is the title of the book?
Tried warming up concentrated liquid glass to make it get soaked up a bit more easily instead of diluting it?
Came across your vid & love the the information, experiments. You did & love love it👍
Thanks for free information...great job,..
Did you try thet in the core?
How much water glass do you need 1 pound of perlite?
What about mixing paper pulp with clay and the fire it after it dries.
How much water glass do you add to one pound of perlite?
I’m still waiting on an answer back from you guys on yr site. I wrote you a few weeks ago . I’m wanting to buy one of yr foam machines to build our home . This fire proofing info is apt for us since our home is in Qld Australia in a fire zone. I’m wanting to build rolling fire walls on the perimeter of our inner landscape, so get back to me mate. Suzy.🙏🇦🇺 ps. I’m planning on making a rocket stove mass heater and outdoor rocket fire bath as well using yr recipes and methodology.
Julie, How do you like your rocket stove now that its all done?
Wow ! Impressive numbers on the heat. Mine only seems to max out at 300°F to 400°F or so.and is not the same mix no perlite or water glass in it...I am sure that must make a big difference running the rocket mass heater.
Wulfy
That's all?
Aren't you sending a lot of creosote into your system at that temperature?
@@priestesslucy no. Actually it does quite well. Have a new one I built with fire brick and it performs great- still not super hot though, but no spot and it lights up and rockets like a charm!
@@wulfclaw4921 where are you measuring this temperature?
@@priestesslucy the barrel top , sides
@@wulfclaw4921 Ohhhhhh, I thought you were doing the Heat Riser measurements (which I don't know how they take them, but yeah the internal heat riser temps get nuts.)
Top of the barrel that sounds about right ^~^
I have an idea for this to be modified to make fireplaces more efficient and effective for heat and cooking, especially when power is down. I believe it will work. I haven't seen it done yet. Maybe I can get the chance to draw it and send it to u to have at it since I cannot build it right now. I think you will change the fireplace world! LOL
I have been pondering several ideas myself .. I hope that he can publish your ideas !!
I'm inspired to make an air/Roman concrete
This is absolutely awesome!! How you feel about making these water glass aircrete for a mobile oven?
Hi there! Hey sobi have pondered "rocket mass heaters" for years.. and I am at place where I can begin work on my third project and this go around I am wanting to "break new ground" in the ascetic/artistic design of the rocket mass heater, on a permanent install. On this build I will be using 30 year old pieces of glass that have the appearance of corrugated metal. The pieces are about ⅝ thick. In my thought process I figured that I would need to make "my own" refractory cement and thats how I found your excellent videos. I would like to share with you my overall design and concepts if you would be willing to share your thoughts on how my design could be better and what I might need to do to improve its long term functionality.
I also have a wife, and we also live in a "small" cabin and she is also concerned about said rocket mass heater going full melt down.
No full meltdown. Not a problem four years later.
Basalt fibers are best for heat insulating
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I'd like to make say a 12" long road maybe 5 inches in diameter drill a 1" = 1 1/2 " hole.. and coat it in your water glass solution.
I want to make a rocket chinmey for an wick oil heater...
Brilliant! I need one of those! I need a RMH too.
what did the fouchomatic people do with theirs? it wasn't portable, but they used cob... clay and grass and such...
Chara Ayars AFAIK, they still have their stove.
What part airlight to perlight?? do u use?
I just bought your plans for the foam maker.
do you think that the rocket stove pipes in the thermal mass sofa system can be adaapted to run though metal pipes buried in screed so that you have an underfloor heated slab?
This is my video instead of Darwin's. He made the stove and the plans over on Honey Do Carpenter. I just test the stove for him. That being said, maybe. We have dropped the pipe twenty four inches without losing momentum of the smoke. Dropping it further into the floor we haven't tried yet. But it's a great idea!
@@dirtpatcheaven thanks. I am planning to run standard underfloor heating water pipes in my dome build floor and heat the water with a central rocket stove, and have a diverter in the chimney to either heat the water or the thermal mass bench. the stove would not be very far up from the floor pipes, its usuaal to bury the pipes in about 3 inches of screed and have tiles laid over, so I wondered about doing away with the heated bench and using the floor as the thermal mass store instead