Alternate Model Rocket Fuel

[doik27]

So right now I really want to make some fuel for my rocket. I cant run out to the store to get the Potassium Nitrate and I haven't got any stump remover so is there any alternate rocket fuel that may be around my house?

[doik27]

or the ingredients to do so?

[Alchemist]

For the fuel you can take almost anything that burns (I've even seen some pyrothecnical mixtures of KNO3 with sugar), but you'll need an oxidizer. So you'll have to get potassium nitrate or something similar. Try to check fertilizers, you'll probably find something with high amount of it (or at least ammonium nitrate, but that doesn't pack as much oxidative power). Also the solubility of KNO3 changes extremely with change of the temperature, so it's easy to get it out of some mixture by recrystallizing.

P.S. Never try disassembling chinese pyrotechnics - there often is KClO3 and it can initiate ignition from attempt to cut the thing open.

[TechnicalK3rbal]

You could also, I think, use saltpeter as an oxidizer.

[doik27]

So I should just wait to get my stump remover to make the r-candy then

[Alchemist]

You could also, I think, use saltpeter as an oxidizer.

It is potassium nitrate (sometimes might be sodium or ammonium nitrate, but the default is KNO3)

[Sillychris]

Fuel is easy. Use anything that burns. Oxidizer, not so easy. Basically anything containing nitrate but you might have to do some work.

Most fertilizers are nitrate rich. With some rudimentary equipment you should be able to extract the nitrates.

Of course, you could just suck it up and go buy the saltpeter. A lot less effort, if you ask me.

[doik27]

Id actually prefer the stump remover and combine it with sugar i.e. r-candy.

[MK3424]

Ever heard of the Pringles Hydrogen rocket?

here you go:

[doik27]

Thats pretty cool, but I will just wait until I can get to the store and make my rocket candy. Thanks guys

[Nuke]

take a log about 4 feet long, bore out the center. attach an oxygen feed to one end and a nozzel to the other. have fun. you can do the same thing with a piece of acrylic too.

[TechnicalK3rbal]

It is potassium nitrate (sometimes might be sodium or ammonium nitrate, but the default is KNO3)

Sorry, didn't know that.

[Skyler4856]

Use sodium and nitrous oxide

[78stonewobble]

Wasn't there someone making solid rocket fuel out of used tires too?

[Alchemist]

Given the composition of rubber, if you add some potassium nitrate you'll get something very close to gunpowder.

[78stonewobble]

Hmm well I found another forums discussing it:

http://www.rocketryforum.com/archive/index.php/t-16927.html

To quote from one of the posts:

Tires consist of cured rubber, carbon black and a bunch of other stuff that is good for tires. Rubber based solid rocket motors use a solid oxidizer such as ammonium perchlorate, usually a metal fuel such as aluminum or magnesium, and a binder, almost always HTPB rubber which acts as both a fuel and a source of the propellant gas.

Binders are the glue that keeps everything together in a solid rocket motor, and after the individual propellant chemicals are mixed, the rubber monomers are ploymerized into rubber. Tire rubbers are already polymerizer so they will not act as a binder unless you to add more rubber monomers to turn a mixture into a solid rubber. This will not make a better propellant than just starting with the proper chemical composition in the first place.

Commercial binders are unpolymerized rubber monomers of Polybutadiene-acrylic acid-acrylonitrile (PBAN) rubber or Hydroxyl-terminated polybutadiene (HTPB) rubber. Below is a drawing of how 1,3-butadiene is polymerized into rubber. By adjusting the curing conditions and the amount of cross-linking additives, you can alter the properties of the polybutadiene rubber. If ammonium perchlorate is used as the oxidizer, these class of propellants are called APCP (ammonium perchlorate composite propellants)

http://upload.wikimedia.org/wikipedia/commons/c/c6/1%2C3-Butadiene_Polymerization.PNG

PBAN gives very slightly higher Isp initially than HTPB as a binder, but doesn't age well, is expensive and has no other commercial use. HTPB has many commercial uses, is inexpensive and ages well, so it is the binder of choice for commercial solid rocket motors. There are enegetic binders such as GAP that will provide a few percent gain in Isp, however these binders are explosives, require special handling, and are again too expensive for all commercial and virtually all military applications.

A good general reference for rocket propulsion in general is

http://www.fas.org/nuke/control/mtcr/text/mtcr_handbook_item4.pdf

EDIT: Does sound like alot of work though and maybe not entirely relevant to the OP's question, but it just popped up.