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APCP help


RedAir

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I've done some research on this propellent and was wondering where you guys pick up the supplies

 

1. AP

2. Epoxy Resin

3. Alum flake

4. Iron oxide (red or brown?)

 

Thanks!

 

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Ya I found everything except epoxy. I heard just about any will work but if anyone has a specific one they like, then I would like to know which one.

 

Do these look good?

 

1. https://www.skylighter.com/products/ammonium-perchlorate?variant=13708227477548

 

3. https://pyro-aluminum.com/?olsPage=products%2F1-lb-indian-blackhead-2-micron-flake-aluminum-shipping-is-included

4. https://www.skylighter.com/products/iron-oxide-red?variant=203821875244

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I've used clear bartop epoxy from Home Depot. It burns quite well and is relatively inexpensive but is difficult to ignite as are many of these types of motors.
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Thanks! Do you know of any calculator like the SRM Richard Nakka program but for APCP propellants? I'm trying to figure out what size motor casing to buy for an E-G class motor

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Those are pretty big motors as a starting point. I would start with getting a good mix then test it in a small container then after successful burns, increase the size.
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Those are pretty big motors as a starting point. I would start with getting a good mix then test it in a small container then after successful burns, increase the size.

 

 

I'm thinking at this point that maybe I'll hold off a while until I perfect my r candy and BP motors. I think I may have underestimated the requirements for using these types of propellents.

 

I guess I see vids like this and I think "why don't I try that?"

Am I being to cautious? How dangerous is this stuff? I would really like to make it but I'm having a hard time finding enough information on it to make a good decision. I have already made nitrocellulose and experimented with zinc sulfur a bit. (I don't trust that zinc stuff)

Edited by RedAir
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YouTube tends to be a bad source of information. That one in particular gives me the strong impression the creator has very little idea what he's talking about.
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YouTube tends to be a bad source of information. That one in particular gives me the strong impression the creator has very little idea what he's talking about.

I totally agree. If you watch some of his other videos he is very unsafe. But unfortunately because of the lack of good videos on APCP, this is what I have to resort to.

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Some of the basic theory may be OK in that vid, BUT most of the method is certainly not safe enough for my liking.

 

Research the available epoxies, look for the NASA Shuttle solid booster compound on other sites, look for info on casting/pressing bates grains, look for info on the core shapes of bates grains related to their burn rates.

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Yes, several BUT you need to try your own Google-Foo and see what you can find too.

 

First off, what is APCP? "APCP is a composite propellant, meaning that it has both fuel and oxidizer mixed with a rubbery binder, all combined into a homogeneous mixture. The propellant is composed of Ammonium perchlorate, an elastomer binder such as Hydroxyl-terminated polybutadiene (HTPB) or Polybutadiene Acrylic Acid Acrylonitrile Prepolymer (PBAN), small amounts of powdered aluminum, and various burn-rate catalysts."

 

There are a lot of wannabee rocket people here and elsewhere that think they know what this and how to make it, perhaps they have even bought some bar top epoxy and had one or two work but that is NOT APCP!

 

Lets get to the actual comp: Ammonium Perchlorate and Hydroxyl-terminated polybutadiene (HTPB) or Polybutadiene Acrylic Acid Acrylonitrile Prepolymer (PBAN).

 

HTPB: https://aeroconsystems.com/cart/motor-making-supplies/htpb-rubber/

 

PBAN kit, complete with a the BOOK: https://www.firefox-fx.com/rocketry.htm

 

Here is one I helped with back in the day: http://www.tripolimn.org/wp-content/uploads/2016/12/Practical-APCP-motor-design.pdf

 

Also look at Richard Nakka: https://www.nakka-rocketry.net/rnx_int.html

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I've actually read through all of those. I really liked the one you helped with! It is going to take me quite a while to really understand it all. The one thing I haven't found is how to actually make it with steps. (like the James Yawn sugar rocket guide). I guess I could figure it out but I would feel a little safer if there was a guide I was following. If you guys are ok with helping me out, I could just order the supplies and ask questions as I go?

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You need the following, https://aeroconsystems.com/cart/literature-software/experimental-composite-propellant/

 

and http://www.burnsim.com/

 

and a mentor that can show you the way. This is one of those things in life you don't do by yourself. Find a Tripoli Rocketry Association Club in or near your area. There are several levels of certification you MUST go through before TRA will allow you to fly those motors. There is a reason they are so strict with their policies, SAFETY!!! SAFETY!!! SAFETY!!!

 

Good luck, please do this the right way and follow everyones advice.

Edited by uncrichie
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I didnt want to have to buy the book if I could find the info but at this point I think I might. I cannot figure out how to install Burnsim on my Mac. I spent a few hours trying to.

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Do some research, get some paper info, do some calculating.

 

Then find a club and a mentor

 

Then start small and progress carefull

 

When these big motors go bad, it's very bad. You need a spacious location where a few catos don't cause a problem.

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Thanks Arthur! I am definitely counting on a few catos before I get it right! I read somewhere that cardboard tubes can take around 1000psi but that seems really high! Edited by RedAir
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Contact Burnsim at BurnSim@blastzone.org they should be able to help you with installation info.

 

Hey, BurnSim Author here. Sorry, but it currently only runs on Windows. Some folks have got it to run under emulators or something, but i'm not a mac guy...

 

The advice to find a mentor and a local Tripoli rocketry club is dead on. And dont waste your time with epoxy, crappy binder for APCP. You want R45/htpb. https://www.rocketmotorparts.com/ is a good supplier, there are others. Most of us doing 'research' motors are buying supplies from surplus suppliers and then splitting it up. There's lots of word of mouth, so and so is buying a drum of something, doing a group buy, etc...

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Remember that if an APCP motor fails while running, there may be a crater, some metal shrapnel and a blast wave. You do not play with one of these in a home environment.

 

The binder is to turn the fuel into a hard but rubbery mass that is slightly flexible enough to stand handling and burning without fracturing.

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Thanks G, nice stuff! https://www.rocketmotorparts.com/Low_Molecular_Weight_Hydroxyl-terminated_Polybutadiene_Resin_1_Gallon/p1577809_16484450.aspx

 

Arthur, are you speaking of metal rocket motor casings? IMHO, whistle rockets have a much more impressive CATO, APCP is just too slow when going up to have even made the explosives list beyond 'low explosive'.

 

https://www.atf.gov/file/60711/download

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Yes! An over pressured metal case or an under designed metal case will simply fragment, possibly more so at temperature.

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