I think you'll get a lot of benefit from a better mixing method. I've done a lot of work with concentrated liquid/solid mixes of consistencies from watery to damn near solid (I almost got a PhD on the topic of slurry rheology). One common factor is that as you get things mixed more uniformly, the liquid becomes easier to manipulate. Having some (60-120 Hz) vibration can work absolute WONDERS for these sort of concentrated slurries, so definitely try that out. Alternatively, you may be able to pre-mix all the solids with the resin (without the 2nd part of the resin added) so you can mix for long time periods without it setting up.
The easier way is to dissolve the solids in a solvent compatible with the resin. Ethanol, methanol, and acetone can usually be used, but ammonium perchlorate is not soluble in ethanol, only partially in acetone. Using a bit of methanol or acetone to dissolve the perchlorate at least partially into a slurry, and then mixing it with the resin should allow a near perfect suspension. The methanol will evaporate before the resin has time to set. The acetone might not, and might make the resin set rubbery.
@@darkfur18 For safety reasons, yes, but for the best performance, you'd want to mill them together, for at least a bit to break up clumps. You can mill them separately down to a few microns particle size, but those particles will form clumps an order of magnitude larger, which will not be broken up by hand-mixing.
@@ElementalMaker I am already giddy with excitement. Although the first one was a bust it was so pretty! First round looked almost crystaline. Maybe that is why it swelled.
Great to see you again. You are always so "up" in your endeavors. Great visit once more. I really do enjoy your posts.You make me feel like a kid again !
the heck? i just started jumping back into researching composite rocketry a couple days ago and this vid pops up! most of this i already knew, but its awesome to see someone actually doing it instead of just buying!
@@ElementalMaker heck yeah! i personally find the idea of building the whole rocket from scratch, engine and all, far more interesting than just buying the complicated parts. it makes it into probably the most interesting and complex puzzle of a hobby i can think of! maybe i should try to make some little videos once i start to try my hand..
I recently had my first successful scratch rocket test. Its a black powder rocket. I made it in the style of a jumping jack; I drilled a hole in the side, this makes it spin and right itself from a lying position, and stabilizes it with a spin, so no extra mass due to not having a stick or fins.
Love that modified 7/8 spade bit. I've got a few odd looking wrenches in my toolbox as well. That's what any good maker does when they need a tool they don't have, but they have something close. Something close gets modified.
One trick you can use to get much better and uniform consistency is to dissolve your perchlorate in a tiny bit of methanol, and then mix this in to your resin. Methanol will act as a thinner to your resin, and will evaporate out before it has time to set, but will allow you to mix everything homogeneously. Ammonium perchlorate just happens to be very soluble in methanol. You can buy it at the hardware store as "methyl hydrate". Careful though, it's toxic, so make sure everything is well ventilated and don't breathe in the vapors. And only use the bare minimum to make it a uniform slurry you can easily mix in the resin, if you use too much the resin will set rubbery. Also, grease the peg in your mold and wrap it in a bit of saran wrap so it easily slides off.
Big change from sugar huh? I think you are right about the nozzle, you can see as the fuel burns, and the core diameter of the grain increases, the pressure rises near the end due to increased surface area of the burn. Some commercial AP motors use a star shaped core to increase the initial surface area, I think its called the web or something. I'm sure the impulse of your fuel will get better as you get more experience but a smaller nozzle is going help overall. I think it's going to make that "chugging" go away. Keep sharing man, I love this stuff. A good mixer will help out bunches too.
'Web' is thickness of the propellant from core to outside. The Kn ratio refers to the ratio between burning surface area and the area of the nozzle throat and is usually between 200 and 400 depending on the propellant and desired chamber pressure, higher the Kn the higher the pressure (and thrust). You can increase the Kn by making the throat diameter smaller or increasing the propellant burning surface area. A STAR or finocyl core of the same diameter as the cylindrical core will increase the burning surface and give you a more neutral burn for long single propellant grains. For multiple short grains, it can up the initial chamber pressure for liftoff. You can see from your graph when the propellant web was thin near the end of the burn, the surface area may have been greater and gave the higher pressure/thrust. On a true 'BATES' grain, as the web gets thinner, the length also gets shorter if burning from both ends giving you a neutral (doesn't change) burn.
I missed this episode when it came out but this is definitely the funniest video you've ever put out.. XD so many funny little comments that can easily go over people's heads if they weren't paying attention I love it! Reminds me of watching a kids cartoon where they add just enough innuendos to keep the parents interested. 😆 I'm pretty sure the parents weren't disinterested in this video and if they were they are getting they're Pyro/man cards taken away because this video was super informative and commical :) thank you now onto other videos I may have missed
We never used a center spindle, we cast the grains solid and drilled them. A bit more waste but we had the flexibility of making various core sizes out of a single batch.
A suggestion only, for the ammonium perchlorate try ball mill to turn it to dust, a cleaner burn and easier mix. As for a fuel source maybe try a magnesium fuel. I love your vid's man. Ofcourse it's live and learn, right? We learn by our mistakes but I think you did very well on your 1st try. Remember that your mixture is crucial for a clean burn. Also I would try narrowing my nozzle just a bit. Again great job, keep up the good work. Opps almost forgot. Maybe fill the tube in layers of one mix at a time, say about in 10mm increments lay at a time.
The particle size of ammonium perchlorate is actually quite critical to its performance. If you powder it, it will just blow the casing. 200 micron and 90 micron are the typical sizes most composite propellants use.
@@ElementalMaker Hey there thanks for the info, I wouldn't want any explosions to be on me. But this might be a little more modern information than what you have obtained. The book you are going by is 1990's information....up dated information can be found on modern rocketry forums. The way modern technology is going we will soon be mixing peanutbutter and charcoal as rocket fuel very soon. Lol www.researchgate.net/profile/Sunil_Jain16/publication/283147266_Size_and_Shape_of_Ammonium_Perchlorate_and_their_Influence_on_Properties_of_Composite_Propellant/links/56fa63ea08ae38d710a3976c/Size-and-Shape-of-Ammonium-Perchlorate-and-their-Influence-on-Properties-of-Composite-Propellant.pdf Down load the pdf file to at least check it out. Anyhow, I am no rocket scientist but this may help. Again man keep up the good work.
I think the problem is your propellant mix. I will have to check my notes, but my propellant ended up rock hard and completely homogeneous. I remember using West's epoxy (used for boats.) I did not use a spindle to cast it. I carefully and very slowly drilled out the spindle hole. In some prior attempts I had the same flame coughing that you had, and I traced it back to uncombusted pieces of propellant clogging up the engine throat. I made some motors about 7 years ago and lit some off this year and there was no degradation at all. Can't wait for the next video.
Late to the party, but a few suggestions. Curing under a vacuum will pull out some of the air voids created while mixing. As you noted, a plasticizer will help. Slightly more of the epoxy catalyst will create more polymer links and give you a stiffer grain. A mix of finer mesh AP will fill the voids between the larger particles and improve solids loading. Awesome first run overall! There is a lot that goes into rocket science - who knew?
Try painting the mold/spindle with polyvinyl alcohol releasing agent, several coats and letting each coat dry, and don't scratch the PVA releasing coat while placing the resin in the mold. It may work better that silicone grease. Also heating up the silicone grease may cause it to permeate into the resin, making it difficult to separate the resin from the mold. Just some thoughts.
I've loved rockets ever since I was in the Rocket Club in Middle School. I'm Now 46 and am still fascinated! I'm enjoying your channel there, Rocket Boy🚀 (BTW, I met Homer at one of his book signings. He grew up close to where I did.) Stay safe 🙉🚀💥🙈
Enjoying your library of videos and keep coming back to the rocket motors. I guess the inner kid in me still needs to be entertained. I've also seen a number of videos where they use polyurethane expanding foam (ie "great stuff") as a binder. Seems to works VERY well. wondering if you MIGHT consider giving that a try. You know...for science?
Had another thought on the way home from work today. Maybe even try a latex-based tire repair ie fix-a-flat. Wouldn't cure like the polyurethane would so "should" stay flexible enough to mold. Not sure how the water content would affect things though.
Space shuttle boosters were Ammonium Perchlorate, Aluminum powder, powdered rubber, and bitumen (tar). The mixture sets after mixing. Later Thikol tried polymerizing the rubber after ingredients mixed and in molds. This rubber bacame stiff at low temps. To save weight the boosters use the ablative nature of the propellant (burning inside to out) to protect booster walls to save weight/money. Space shuttle accident when launched at lo temp.
Well that was great. I am guessing you consider this a "lose one" situation and for that reason i subbed. I like it when people show things that do not go to plan because that is real life and i personally learn a lot from not so hot tests of things. Thanks for sharing.
Great video, thank you! P.S. Warning! Be careful when lubing your spindle, make sure you lube it slowly. If you lube your spindle too quickly it could go off in your hand and may possibly put your eye out...
I'm going to try a few different release agents before moving to physical barriers. My concern is if they stick to the propellant it will interfere with the burn propagation.
12V power supply look primary side for small electrolytics, 47-220uF around 16-35V, they will be faulty with no visible signs. That and the output caps are the most common failure on small SMPS units, I keep a whole kit of the capacitors around for repair of them.
i take my xtra and flatten it in a ziplock then use a pizza cutter to cut square stars while its about half baked and use those for fire starters and pyrotechnic stars .the magnalium ones burn bright as hell .but blue CuO is my favorite ,its a gorgeous blue and smokeless burn too
In order to stop it sticking to the spindle, can you use the paper casing for the propellant to cover the spindle? like use a small diameter cylinder to cover it ?
Wow that rubbery stuff looks like a mare to work with! I might be missing something but surely a slightly tapered core spindle would help the de-moulding process. as well as properly polishing the spindle to get rid of any remaining machining marks (even fine scratches can load-up and cause sticking). core-burner spindles can be a tricky balance between too much taper (if they go to a point it can cause detonation faliure, I don't know why but it never worked for me) or too little taper, causing sticking when removing the spindle, (i've cracked a few that way too!) my only experience is with hand-rammed BP and a little RC though so don't take this as advise, just idle speculation! Thanks dude, I look forward to seeing how this goes
Would a solid mold release agent maybe be a better idea? Talc or chalk powder possibly? Also, I hope this one failure doesn't mean you won't be doing more composite fuel soon with a smaller nozzle.
I'm going to experiment with some spray on mod releases which should perform much better. If not ill try physical barriers and powdered release agents.
@@ElementalMaker follow-up question: is there a reason graphite seems to be the dominant material choice for the nozzle on these level rockets? It seems like it's not the most durable material on it's own, which is an odd choice for something that gets exposed to supersonic gases
Those rectifier diodes look like they have been running hot if that is discolouration of the board around them, the output capacitor may have failed short or at least drawing enough current to cause the control ic to activate over current shut down. A good start would be replace all the electrolytic capacitors,check the input and output rectifier diodes and replace any failed, look for any other discolouration on pcb,testing components in that area (most likely resistors or small diodes). Also wash the board if that (or any) capacitor has leaked on the board. Will most likely be ok and work after that.
ammoniom chlorates and perchlorates are used in a lot of HME's if I'm not mistaken, so I'm not really surprised they work as propellant as well, since they are powerful oxydisers
@@ElementalMaker Yes, which makes it easy to make into explosies, in a very unsafe process and An even more dangerous end product, ofcourse. Tatp ain't no joke
Try adding a spacer between the grain and the convergent zone. Without it, the gases are just being forced straight out of the bore. Doing that helped my sugar rocket motors.
According to the professional mold making sites for halloween masks and whatnot, silicone sticks to other silicates and silicone. Maybe change up your release agent to something different. Vaseline? Your burn rate problems may be related to the lack of a proper burn rate catalyst. NASA uses aluminum. I'd start there. A faster burn will increase chamber pressure. There's a formula for ideal nozzle size somewhere.
Try ultra fine graphite powder as lube/release agent. While it will slow down the burn locally, it shouldn't react otherwise and theoretically should work well as a release agent. Also did you think about mixing up your dry ingredients before adding them to the wet? It should be the same as baking, you get a better blend mixing your dry ingredients separately before adding the wet.
Lithium perchlorate apparently gives even higher specific impulse than ammonium perch. The problem arises from its high hygroscopicity- it has to be sealed in something like wax to keep moisture out
I wonder why that is. Ammonium perchlorate is so good because it's fully gaseous combustion products, but with lithium you would get some solid combustion products.
Was certainly the smoothing cap. The smoothing cap sits across the +/i, and when caps bulge or die, they tend to go closed circuit. Which would be shorting out your supply, which is probably current limited, which explain the voltage of 300mv across the dead short of the cap.
I remember when I tried to make a rocket and had the bright idea to use rocket fuel to make a cannon. Of course, the cannon was made of PVC and aluminum tape. And then I used a fishing weight wrapped in aluminum as a projectile. I'm pretty damn happy I sucked at measuring because I nearly pipe bombed myself. Had a friend who wasn't so luck and hammered a piece of buckshot into the end of a 223 and ended up with brass shrapnel bits in his leg, he's doing good now.
Jeeze those are both scary close calls. Glad your both okay. When I was a young boy I also had a couple similar close calls. One nearly cost me my right hand, and the other ended up with an arrow stuck half way through the gutter of a neighbors house, but it could have just as easily hit me or my cousin. Never shoot an arrow straight up in the air LOL. That was an awkward conversation with the neighbor.
On the power supply: The dead output cap can definitely cause it to stop working completely. The control chip will notice something is wrong and shut down. (and try to restart from time to time)
Suggestion: hook up with a Tripoli rocket club member that does experimental motors. They will have a Kitchenaid mixer and a vacuum pump to de-gas the mix. It helps.
I'd love to find a tripoli member in the area. I have the equipment for degassing and I've been on the lookout for a used kitchenaid mixer on FB Marketplace and Craigslist. But I'd love to work with someone experienced
ElementalMaker I’ve been watching your channel for awhile now and I love your vids. After I watched you build that hho generator I had to make one and it was pretty crazy. I used to make model rockets and experiment with different fuel mixes and additives. After seeing this I might have to get back into it. Can’t wait to see you hit 50k subs!
Do you have any stability issues using lampblack with AP? Lampblack is made from petroleum soot and can have some acid component to it (low pH). Ever tried using airfloat charcoal instead?
Never had any issues, but I also buy high quality pyrotechnic grade lampblack. Id imagine any potential acid has been neutralized in processing. I haven't tried airfloat charcoal, but I imagine it may work similarly.
I wouldn't make those assumptions :) Even the lampblack that Harry Gilliam at Skylighter was not necessarily the best. Air float charcoal was better. Besides, air float didn't make the damn mess lampblack does. I used to always add a little bit of some carbonate to my mix if I was using lampblack and AP or KClO3
Stump remover granules and granulated white sugar mix 50/50 weight and heat mix while heating use lowest heat only need to melt sugar has a higher melting point than stump remover...ignite with torch or otherwise and dont close it off in a container of any sort
Amigo, I appreciate your antiquarian enthusiasm for archaic tech and commend your bravery in exposing yourself to unequivocal harm by way of the biohazardous chemicals. There are not many people who retain an interest in grandpa’s pollution sticks we call rocketry after becoming aware of the near-century-old and non-polluting tech of electro-gravitics, which produces orders of magnitude greater thrust than rocketry ever could, at a miniscule fraction of the cost. And given the low current requirement, the high voltage, DC pulsed electricity remains within the realm of possibilities for garage tinkerers and citizen scientists everywhere. Yet I commend your bravery, and for keeping grandpas pollution sticks alive. You’ve got balls of steel, and thank goodness for your usage of safety equipment, ‘cause that shit is plain nutz, if you ask me. F.
@H.E Master In english, he says we should use antigravity instead of chemical rockets because of pollution. I'd love to do that, but there are zero reproducible gravity modification experiments.
I’m a little late for the party, but did you notice much if any corrosion inside the engine after the burn caused by the HCl production in the burn? These videos are very instructional.
Thank you! The corrosion in the motor casing seems to be quite minimal, mostly relagated to the bulkhead of the motor, and the small exposed area around the graphite nozzle insert. I also think the judicious application of antisieze grease I do probably helps quite a bit.
Nice work. I'm wondering if you kept the propellant from expanding during curing whether or not that might help improve the burn performance. Thanks for sharing!
Some random thoughts for you. Send the dead power supply to Big Clive. Wrap the spindle with some paper or even wax paper. Last if you like experimenting why not use some two part clear coat?
Holy shit, this composite does not mess around. I'm just glad you are doing that so I don't even have to think about trying it myself. thanks for the efforts!
One time I caight the benjamin franklin crafts going out of business and damn near bought all their estes engines for like almost 90% off!! In about 92 i was a born again. Makin my own would advance the cause.
Have you given any thought to nitrocellulose based rockets? Would be fun to mess with I think.... see if & what additives would make it better/worse...
I really like ur rocket testing vids. I'm not really an electronics board person or computer code person but I really am interested in ur test stand. I've read the article u linked & I'm wondering how hard it is to create this test stand? What type of software runs it on ur laptop? I'm getting into hobbyist pyro & love the idea of rockets. There's thrust test stands available for like a few hundred possibly more I can't remember the number off the top of my head. I know testing rockets is a big part of it so it'd probably be a necessary tool in the shop especially when dealing with new comps. Have you ever tried ramming powdered KNSU comp onto a spindle in a cardboard casing. Get back to me at ur convenience. Thanks. Keep up the amazing vids.
![Felix "Unfair" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/Oswujxm2Ag0/mqdefault.jpg)
Not disappointed at all, it shows perfectly how experimental results teach us to get better future results, thanks dude 👍
Very well said Mike 👍. Glad you enjoyed!
I love your vid’s and especially these rocket ones
Thanks Luke and Jeff!
I think you'll get a lot of benefit from a better mixing method. I've done a lot of work with concentrated liquid/solid mixes of consistencies from watery to damn near solid (I almost got a PhD on the topic of slurry rheology). One common factor is that as you get things mixed more uniformly, the liquid becomes easier to manipulate. Having some (60-120 Hz) vibration can work absolute WONDERS for these sort of concentrated slurries, so definitely try that out. Alternatively, you may be able to pre-mix all the solids with the resin (without the 2nd part of the resin added) so you can mix for long time periods without it setting up.
I wonder if it would benefit from some Gentle milling Before adding the curing agent?
@@gazzarrr666 I'd feel sketchy milling a fuel/oxidizer mix, but if it's being done outdoors, or in an unoccupied area, perhaps/
The easier way is to dissolve the solids in a solvent compatible with the resin. Ethanol, methanol, and acetone can usually be used, but ammonium perchlorate is not soluble in ethanol, only partially in acetone. Using a bit of methanol or acetone to dissolve the perchlorate at least partially into a slurry, and then mixing it with the resin should allow a near perfect suspension. The methanol will evaporate before the resin has time to set. The acetone might not, and might make the resin set rubbery.
@@Nuovoswiss Wouldn't you wanna mill the fuel and oxidizer separately, anyways?
@@darkfur18 For safety reasons, yes, but for the best performance, you'd want to mill them together, for at least a bit to break up clumps. You can mill them separately down to a few microns particle size, but those particles will form clumps an order of magnitude larger, which will not be broken up by hand-mixing.
"This kinda rubber won't really fit in your wallet"
I have never watched this channel before, but you have my attention
👍👍 Thanks!
What if i have a huge wallet?
@@crackedemerald4930 oh you sweet innocent child
One change at a time please :)
Narrower nossle first, then catalyst. If you do both at once we will never know and that'll drive me crazy!
That's exactly what I'm doing! Got another batch of this propellant cured and ready to test with a 6.3mm nozzle.
@@ElementalMaker I am already giddy with excitement. Although the first one was a bust it was so pretty!
First round looked almost crystaline. Maybe that is why it swelled.
Its always a pleasure watching you especially as you have a perfect TV /documentary voice,
I could watch you all night.
Great to see you again. You are always so "up" in your endeavors. Great visit once more. I really do enjoy your posts.You make me feel like a kid again !
The 7/8” Zimbabwe spear tip is my go to tool when machining on the mini lathe
I've been excited for this one since you posted that teaser pic! And now I'm going to stop typing and enjoy the vid. :) Thanks for sharing!
Dude, lighting that puck made my day. I was on the edge of my seat waiting for the grain
the heck? i just started jumping back into researching composite rocketry a couple days ago and this vid pops up! most of this i already knew, but its awesome to see someone actually doing it instead of just buying!
I don't know if I'm 'doing it' just yet, but I'm sure as hell trying! Glad to see some other rocketeers on here
@@ElementalMaker heck yeah! i personally find the idea of building the whole rocket from scratch, engine and all, far more interesting than just buying the complicated parts. it makes it into probably the most interesting and complex puzzle of a hobby i can think of!
maybe i should try to make some little videos once i start to try my hand..
"we should've hired an asthmatic chain-smoking, grandpa with emphysema..." freaking priceless. You're awesome. subscribed.
lmfao at 12:07 🤣🤣 as the fuse has a little propulsion of it's own.
I recently had my first successful scratch rocket test. Its a black powder rocket.
I made it in the style of a jumping jack; I drilled a hole in the side, this makes it spin and right itself from a lying position, and stabilizes it with a spin, so no extra mass due to not having a stick or fins.
Love that modified 7/8 spade bit. I've got a few odd looking wrenches in my toolbox as well. That's what any good maker does when they need a tool they don't have, but they have something close. Something close gets modified.
The rule is that if it's stupid and it works it's not stupid. :)
You make me want to start shooting rockets again. I haven't launched one since about 1983, but your vids remind me of how much fun it was.
Finally.... it only took 10 months. Hope Im around for the next rocket motor build because we are ALL waiting for another great video!
Love the video man, would love to see a follow up with a smaller throat diameter. Such a pretty flame too, cant wait to see some blue or green in it
One trick you can use to get much better and uniform consistency is to dissolve your perchlorate in a tiny bit of methanol, and then mix this in to your resin. Methanol will act as a thinner to your resin, and will evaporate out before it has time to set, but will allow you to mix everything homogeneously. Ammonium perchlorate just happens to be very soluble in methanol. You can buy it at the hardware store as "methyl hydrate". Careful though, it's toxic, so make sure everything is well ventilated and don't breathe in the vapors. And only use the bare minimum to make it a uniform slurry you can easily mix in the resin, if you use too much the resin will set rubbery. Also, grease the peg in your mold and wrap it in a bit of saran wrap so it easily slides off.
Big change from sugar huh? I think you are right about the nozzle, you can see as the fuel burns, and the core diameter of the grain increases, the pressure rises near the end due to increased surface area of the burn. Some commercial AP motors use a star shaped core to increase the initial surface area, I think its called the web or something. I'm sure the impulse of your fuel will get better as you get more experience but a smaller nozzle is going help overall. I think it's going to make that "chugging" go away. Keep sharing man, I love this stuff. A good mixer will help out bunches too.
'Web' is thickness of the propellant from core to outside. The Kn ratio refers to the ratio between burning surface area and the area of the nozzle throat and is usually between 200 and 400 depending on the propellant and desired chamber pressure, higher the Kn the higher the pressure (and thrust). You can increase the Kn by making the throat diameter smaller or increasing the propellant burning surface area. A STAR or finocyl core of the same diameter as the cylindrical core will increase the burning surface and give you a more neutral burn for long single propellant grains. For multiple short grains, it can up the initial chamber pressure for liftoff. You can see from your graph when the propellant web was thin near the end of the burn, the surface area may have been greater and gave the higher pressure/thrust. On a true 'BATES' grain, as the web gets thinner, the length also gets shorter if burning from both ends giving you a neutral (doesn't change) burn.
Don't beat yourself up!!! You'll get it dialed. No smoke propelant. Way to go. Keep at it Maker!!!
I missed this episode when it came out but this is definitely the funniest video you've ever put out.. XD so many funny little comments that can easily go over people's heads if they weren't paying attention I love it! Reminds me of watching a kids cartoon where they add just enough innuendos to keep the parents interested. 😆 I'm pretty sure the parents weren't disinterested in this video and if they were they are getting they're Pyro/man cards taken away because this video was super informative and commical :) thank you now onto other videos I may have missed
Well, it sure looked impressive. Now i really want to see what it can do when this gets tuned in.
ruclips.net/video/uidwwcRPNg4/видео.html
Chuggle (Rocketry): Verb. To vary in power output over time.
Flame was beautiful when it finally stabilized at the end. Really nice, can't wait to see more composites.
Thank you!
We never used a center spindle, we cast the grains solid and drilled them. A bit more waste but we had the flexibility of making various core sizes out of a single batch.
A suggestion only, for the ammonium perchlorate try ball mill to turn it to dust, a cleaner burn and easier mix. As for a fuel source maybe try a magnesium fuel.
I love your vid's man. Ofcourse it's live and learn, right? We learn by our mistakes but I think you did very well on your 1st try. Remember that your mixture is crucial for a clean burn. Also I would try narrowing my nozzle just a bit.
Again great job, keep up the good work.
Opps almost forgot. Maybe fill the tube in layers of one mix at a time, say about in 10mm increments lay at a time.
The particle size of ammonium perchlorate is actually quite critical to its performance. If you powder it, it will just blow the casing. 200 micron and 90 micron are the typical sizes most composite propellants use.
@@ElementalMaker
Hey there thanks for the info, I wouldn't want any explosions to be on me.
But this might be a little more modern information than what you have obtained. The book you are going by is 1990's information....up dated information can be found on modern rocketry forums. The way modern technology is going we will soon be mixing peanutbutter and charcoal as rocket fuel very soon. Lol
www.researchgate.net/profile/Sunil_Jain16/publication/283147266_Size_and_Shape_of_Ammonium_Perchlorate_and_their_Influence_on_Properties_of_Composite_Propellant/links/56fa63ea08ae38d710a3976c/Size-and-Shape-of-Ammonium-Perchlorate-and-their-Influence-on-Properties-of-Composite-Propellant.pdf
Down load the pdf file to at least check it out. Anyhow, I am no rocket scientist but this may help. Again man keep up the good work.
I think the problem is your propellant mix. I will have to check my notes, but my propellant ended up rock hard and completely homogeneous. I remember using West's epoxy (used for boats.) I did not use a spindle to cast it. I carefully and very slowly drilled out the spindle hole. In some prior attempts I had the same flame coughing that you had, and I traced it back to uncombusted pieces of propellant clogging up the engine throat. I made some motors about 7 years ago and lit some off this year and there was no degradation at all. Can't wait for the next video.
Late to the party, but a few suggestions. Curing under a vacuum will pull out some of the air voids created while mixing. As you noted, a plasticizer will help. Slightly more of the epoxy catalyst will create more polymer links and give you a stiffer grain. A mix of finer mesh AP will fill the voids between the larger particles and improve solids loading.
Awesome first run overall! There is a lot that goes into rocket science - who knew?
Try painting the mold/spindle with polyvinyl alcohol releasing agent, several coats and letting each coat dry, and don't scratch the PVA releasing coat while placing the resin in the mold. It may work better that silicone grease. Also heating up the silicone grease may cause it to permeate into the resin, making it difficult to separate the resin from the mold. Just some thoughts.
This is such an underrated channel. Love it so much.
First time i've ever seen that scale so clean
I've loved rockets ever since I was in the Rocket Club in Middle School. I'm Now 46 and am still fascinated! I'm enjoying your channel there, Rocket Boy🚀 (BTW, I met Homer at one of his book signings. He grew up close to where I did.) Stay safe 🙉🚀💥🙈
Enjoying your library of videos and keep coming back to the rocket motors. I guess the inner kid in me still needs to be entertained. I've also seen a number of videos where they use polyurethane expanding foam (ie "great stuff") as a binder. Seems to works VERY well. wondering if you MIGHT consider giving that a try. You know...for science?
Whoa never even thought to use that but I could certainly see it working. Probably just needs a good degassing. I'll definitely have to try that
Had another thought on the way home from work today. Maybe even try a latex-based tire repair ie fix-a-flat. Wouldn't cure like the polyurethane would so "should" stay flexible enough to mold. Not sure how the water content would affect things though.
Space shuttle boosters were Ammonium Perchlorate, Aluminum powder, powdered rubber, and bitumen (tar). The mixture sets after mixing. Later Thikol tried polymerizing the rubber after ingredients mixed and in molds. This rubber bacame stiff at low temps. To save weight the boosters use the ablative nature of the propellant (burning inside to out) to protect booster walls to save weight/money. Space shuttle accident when launched at lo temp.
Have you thought about an arbor press with some custom aluminum press jigs to help extract the spindle and the grain? Just a though.
Well that was great.
I am guessing you consider this a "lose one" situation and for that reason i subbed.
I like it when people show things that do not go to plan because that is real life and i personally learn a lot from not so hot tests of things.
Thanks for sharing.
Much appreciated Jason! Thanks for your sub!
Great video, thank you!
P.S. Warning! Be careful when lubing your spindle, make sure you lube it slowly. If you lube your spindle too quickly it could go off in your hand and may possibly put your eye out...
@ElementalMaker you could put a cigarretpaper around the innercore to prevent it from sticking.
I'm going to try a few different release agents before moving to physical barriers. My concern is if they stick to the propellant it will interfere with the burn propagation.
Use Partel Paste wax release agent, spread it on anything you don't want an epoxy to bond to. That's what the composites industry uses.
12V power supply look primary side for small electrolytics, 47-220uF around 16-35V, they will be faulty with no visible signs. That and the output caps are the most common failure on small SMPS units, I keep a whole kit of the capacitors around for repair of them.
This was awesome. I wanna see a video with jeorge absolutely! Way to go man
I hate it when I chuggle too. It tends to also keep me from reaching optimal chamber pressure. :) Keep up the good work!
I didn't know hylians knew how to make ammonium perchlorate and resin, good for them for being such great scholars.
i take my xtra and flatten it in a ziplock then use a pizza cutter to cut square stars while its about half baked and use those for fire starters and pyrotechnic stars .the magnalium ones burn bright as hell .but blue CuO is my favorite ,its a gorgeous blue and smokeless burn too
i am sure this guy is the malefic twin of Ave ;)
Fantastic video! Love the rocket ones!
In order to stop it sticking to the spindle, can you use the paper casing for the propellant to cover the spindle? like use a small diameter cylinder to cover it ?
Awesome video as always!
Wow that rubbery stuff looks like a mare to work with! I might be missing something but surely a slightly tapered core spindle would help the de-moulding process. as well as properly polishing the spindle to get rid of any remaining machining marks (even fine scratches can load-up and cause sticking).
core-burner spindles can be a tricky balance between too much taper (if they go to a point it can cause detonation faliure, I don't know why but it never worked for me) or too little taper, causing sticking when removing the spindle, (i've cracked a few that way too!) my only experience is with hand-rammed BP and a little RC though so don't take this as advise, just idle speculation! Thanks dude, I look forward to seeing how this goes
Would a solid mold release agent maybe be a better idea? Talc or chalk powder possibly? Also, I hope this one failure doesn't mean you won't be doing more composite fuel soon with a smaller nozzle.
I'm going to experiment with some spray on mod releases which should perform much better. If not ill try physical barriers and powdered release agents.
@@ElementalMaker follow-up question: is there a reason graphite seems to be the dominant material choice for the nozzle on these level rockets? It seems like it's not the most durable material on it's own, which is an odd choice for something that gets exposed to supersonic gases
The rocket flame looks very nice!
Make the ammonium perchlorate into a finer powder to make it more dough-like. I’m guessing that was the reason for the inconsistent burn
Those rectifier diodes look like they have been running hot if that is discolouration of the board around them, the output capacitor may have failed short or at least drawing enough current to cause the control ic to activate over current shut down. A good start would be replace all the electrolytic capacitors,check the input and output rectifier diodes and replace any failed, look for any other discolouration on pcb,testing components in that area (most likely resistors or small diodes). Also wash the board if that (or any) capacitor has leaked on the board. Will most likely be ok and work after that.
way to go bud.keep it going youll probably go thru a dozen trials untill you get the recipe perfected for you
Interesting work.
no-no. you got a lot of great data. this classifies now where close to disappointing. learning something is priceless
ammoniom chlorates and perchlorates are used in a lot of HME's if I'm not mistaken, so I'm not really surprised they work as propellant as well, since they are powerful oxydisers
Ammonium chlorate is some very unstable stuff!
@@ElementalMaker Yes, which makes it easy to make into explosies, in a very unsafe process and An even more dangerous end product, ofcourse. Tatp ain't no joke
Try adding a spacer between the grain and the convergent zone. Without it, the gases are just being forced straight out of the bore. Doing that helped my sugar rocket motors.
I did enjoy your video, thank you.
u need a smaller grain size almost like powdered sugar
Awesome bro 👍👍💯💯💯💯💯💯💯🔥🔥🔥🔥🔥🔥🔥🔥🔥🔥🔥🔥🔥✨✨✨✨✨✨✨✨
According to the professional mold making sites for halloween masks and whatnot, silicone sticks to other silicates and silicone. Maybe change up your release agent to something different. Vaseline? Your burn rate problems may be related to the lack of a proper burn rate catalyst. NASA uses aluminum. I'd start there. A faster burn will increase chamber pressure. There's a formula for ideal nozzle size somewhere.
Try ultra fine graphite powder as lube/release agent. While it will slow down the burn locally, it shouldn't react otherwise and theoretically should work well as a release agent. Also did you think about mixing up your dry ingredients before adding them to the wet? It should be the same as baking, you get a better blend mixing your dry ingredients separately before adding the wet.
Lithium perchlorate apparently gives even higher specific impulse than ammonium perch. The problem arises from its high hygroscopicity- it has to be sealed in something like wax to keep moisture out
I wonder why that is. Ammonium perchlorate is so good because it's fully gaseous combustion products, but with lithium you would get some solid combustion products.
This is by far one of the best and informative rocketry videos, thanks for taking your time to share your knowledge. 👍
Thank you! Glad you enjoyed!
I've made apcp motors with black copper oxide added and can confirm it adds a beautiful bright blue flame
Was certainly the smoothing cap. The smoothing cap sits across the +/i, and when caps bulge or die, they tend to go closed circuit. Which would be shorting out your supply, which is probably current limited, which explain the voltage of 300mv across the dead short of the cap.
Great tip, I'll have to try replacing that capacitor and see if that fixes the supply
I remember when I tried to make a rocket and had the bright idea to use rocket fuel to make a cannon. Of course, the cannon was made of PVC and aluminum tape. And then I used a fishing weight wrapped in aluminum as a projectile. I'm pretty damn happy I sucked at measuring because I nearly pipe bombed myself. Had a friend who wasn't so luck and hammered a piece of buckshot into the end of a 223 and ended up with brass shrapnel bits in his leg, he's doing good now.
Jeeze those are both scary close calls. Glad your both okay. When I was a young boy I also had a couple similar close calls. One nearly cost me my right hand, and the other ended up with an arrow stuck half way through the gutter of a neighbors house, but it could have just as easily hit me or my cousin. Never shoot an arrow straight up in the air LOL. That was an awkward conversation with the neighbor.
On the power supply: The dead output cap can definitely cause it to stop working completely. The control chip will notice something is wrong and shut down. (and try to restart from time to time)
Suggestion: hook up with a Tripoli rocket club member that does experimental motors. They will have a Kitchenaid mixer and a vacuum pump to de-gas the mix. It helps.
I'd love to find a tripoli member in the area. I have the equipment for degassing and I've been on the lookout for a used kitchenaid mixer on FB Marketplace and Craigslist. But I'd love to work with someone experienced
Always enjoy
A rocket vid and its monetised?!?😅😂👏🏼👍🏼
Still a cool project!
A smaller nozzle will result in a higher chamber pressure which should cause the burn rate to be a bit quicker, hopefully increasing thrust
That's the plan for the next go round!
ElementalMaker I’ve been watching your channel for awhile now and I love your vids. After I watched you build that hho generator I had to make one and it was pretty crazy. I used to make model rockets and experiment with different fuel mixes and additives. After seeing this I might have to get back into it. Can’t wait to see you hit 50k subs!
Do you have any stability issues using lampblack with AP? Lampblack is made from petroleum soot and can have some acid component to it (low pH). Ever tried using airfloat charcoal instead?
Never had any issues, but I also buy high quality pyrotechnic grade lampblack. Id imagine any potential acid has been neutralized in processing. I haven't tried airfloat charcoal, but I imagine it may work similarly.
I wouldn't make those assumptions :) Even the lampblack that Harry Gilliam at Skylighter was not necessarily the best. Air float charcoal was better. Besides, air float didn't make the damn mess lampblack does. I used to always add a little bit of some carbonate to my mix if I was using lampblack and AP or KClO3
Stump remover granules and granulated white sugar mix 50/50 weight and heat mix while heating use lowest heat only need to melt sugar has a higher melting point than stump remover...ignite with torch or otherwise and dont close it off in a container of any sort
Very interesting 👍 the burn of the left over was fun very reactive.
Have you tried a spray mold release, like what's available on McMaster-Carr? There is at least one that is PTFE based.
Got a couple new release agents I will try in future batches. One is a spray on type
Amigo, I appreciate your antiquarian enthusiasm for archaic tech and commend your bravery in exposing yourself to unequivocal harm by way of the biohazardous chemicals. There are not many people who retain an interest in grandpa’s pollution sticks we call rocketry after becoming aware of the near-century-old and non-polluting tech of electro-gravitics, which produces orders of magnitude greater thrust than rocketry ever could, at a miniscule fraction of the cost. And given the low current requirement, the high voltage, DC pulsed electricity remains within the realm of possibilities for garage tinkerers and citizen scientists everywhere.
Yet I commend your bravery, and for keeping grandpas pollution sticks alive. You’ve got balls of steel, and thank goodness for your usage of safety equipment, ‘cause that shit is plain nutz, if you ask me.
F.
@H.E Master In english, he says we should use antigravity instead of chemical rockets because of pollution. I'd love to do that, but there are zero reproducible gravity modification experiments.
Maybe I'm just crazy but You may want to dehydrate that AP a bit and blitz it in the blender a bit. It seemed really coarse.
I’m a little late for the party, but did you notice much if any corrosion inside the engine after the burn caused by the HCl production in the burn? These videos are very instructional.
Thank you! The corrosion in the motor casing seems to be quite minimal, mostly relagated to the bulkhead of the motor, and the small exposed area around the graphite nozzle insert. I also think the judicious application of antisieze grease I do probably helps quite a bit.
Nice work. I'm wondering if you kept the propellant from expanding during curing whether or not that might help improve the burn performance.
Thanks for sharing!
Hey what was the website you were buying your supplies from? I couldn't quite catch it and didn't see it in the description. Awesome video!
Some random thoughts for you. Send the dead power supply to Big Clive. Wrap the spindle with some paper or even wax paper.
Last if you like experimenting why not use some two part clear coat?
Holy shit, this composite does not mess around. I'm just glad you are doing that so I don't even have to think about trying it myself. thanks for the efforts!
Have you tried having a casing and nozzle made out of Macor ceramic?
This guy is like a mix between Cody's lab and Ave, I like it
One time I caight the benjamin franklin crafts going out of business and damn near bought all their estes engines for like almost 90% off!! In about 92 i was a born again. Makin my own would advance the cause.
Maybe the heat caused some APC to decompose, and the gases caused the mix to expand. Or maybe something in that particular resin reacted with it.
good experiment! always cool
Where do you get good lampblack? Or decent willow charcoal? Not paying by the ounce for pigment or pencils? Thanks!
Any pyrotechnic supplier will have both at far more reasonable prices, skylighter, pyrochemsource, Firefox etc
Also, I'd cover your metal testing plates and stuff with an extremely basic paste so that the hydrochloric acid doesn't destroy it.
to help eliminate bubbles in your casing connect a vacuum pump to your curing chamber
As usual great video KEEP UP
Keep 'em coming!
Maybe try wrapping baking paper around the centre plug of the mold instead of using silicone grease.
Have you given any thought to nitrocellulose based rockets? Would be fun to mess with I think.... see if & what additives would make it better/worse...
Thanks for showing me its features! Hah hah hah
I really like ur rocket testing vids. I'm not really an electronics board person or computer code person but I really am interested in ur test stand. I've read the article u linked & I'm wondering how hard it is to create this test stand? What type of software runs it on ur laptop? I'm getting into hobbyist pyro & love the idea of rockets. There's thrust test stands available for like a few hundred possibly more I can't remember the number off the top of my head. I know testing rockets is a big part of it so it'd probably be a necessary tool in the shop especially when dealing with new comps. Have you ever tried ramming powdered KNSU comp onto a spindle in a cardboard casing. Get back to me at ur convenience. Thanks. Keep up the amazing vids.