Best Fuel For Combustion ?

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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Northir
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Mon Sep 28, 2009 2:27 am

Whats the Best fuel for a standard combustion cannon, that you have found ive been using spray paint, it does not seem to work to well


(sorry about the original question)

Edited by jrrdw.
Last edited by Northir on Mon Sep 28, 2009 2:54 am, edited 2 times in total.
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jackssmirkingrevenge
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Mon Sep 28, 2009 2:30 am

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Discussion of solid propellants, explosive devices or incendiary projectiles fired specifically from a spud cannon is prohibited, and may result in a permanent banning of your account.For the purpose of this forum, these definitions will be used:
Solid propellant: Any substance containing all the chemical elements required to enable sustained combustion without the presence of additional oxidizers. This includes but is not limited to gunpowder, thermite, and many commercial and/or homemade pyrotechnic compounds.
For this purpose, nitroglycerine, though liquid, would qualify.

For this purpose, ordinary flour, though solid, would not qualify.
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MrCrowley
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Mon Sep 28, 2009 3:17 am

Northir wrote:Whats the Best fuel for a standard combustion cannon, that you have found ive been using spray paint, it does not seem to work to well


(sorry about the original question)
Haha yeah spray paint wont work very well, it's not pure enough, has too much crap in it.

The safest best fuel I'd say is MAPP gas. Sure you can use oxy/acetylene but you have to make the cannon from metal, defnitely not PVC.

With MAPP and Propane as fuel, you should look at fuel meters and fans to increase performance.
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Northir
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Mon Sep 28, 2009 3:24 am

Funny thing i just happen to have some MAPP out in my truck, how would you suggest getting it into my combustion chamber, i have a torch valve and a ton of fittings
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MrCrowley
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Mon Sep 28, 2009 3:26 am

You also have a website at your disposal with more than enough information to answer your question...not to mention several how-to's and an explanation on the Wiki.
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Northir
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Mon Sep 28, 2009 3:30 am

:P good call, ill get plugging away
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MrCrowley
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Mon Sep 28, 2009 3:31 am

It's gonna be a long few hours :D

It's pretty easy to implement, you just need to read up on the fuel measuring really.
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Northir
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Mon Sep 28, 2009 3:39 am

yea, soon after asking what the best way to get it into my Combustion chamber i found 4 fittings that i can use to replace the torch outlet, so its just a matter of like you said reading up on measurements
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Mon Sep 28, 2009 10:55 am

Do you have a large syringe lying around? If you do you can get up and running as soon as the rest of the gun is built.

A syringe is as accurate as any other type of metering system and usually only costs a couple bucks. A syringe isn't as fast as a dedicated meter, and doesn't have the bling factor, but it'll get all the performance out'a the gun that there is to get.

http://www.spudfiles.com/spud_wiki/index.php/Fuel_meter
http://www.spudfiles.com/spud_wiki/inde ... n_Spudguns

Just need a short length of hose, the syringe and the standard Bernzomatic torch head. Unscrew and remove the air mixer from the torch (it can be put back on so you aren't hurting the torch head).
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Sun Oct 04, 2009 5:17 pm

If you want bang for your buck then Any old body spray or deoderant not thhe dry stuff though
As it leaves a horrible chalky residue in the chamber.
Hairspray is also a no for me as it leaves. A gunk on your ignion source
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If you're looking for an aerosol, the only two I've found to work acceptably are static guard and starter fluid... and it takes a very large combustion chamber to use starting fluid reliably.

Really, just go with propane or MAPP gas is what I'd say.

To make this seem less like an echo, here's a link to the page on my site with the bulk of the theory.
VirusX
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Tue Oct 06, 2009 8:29 am

Don't use that shit called deodorant. It makes a good BOOM but the combustion champer gets wet very fast and after a few shots you'll get ignition problems. It smells bad and attacks your screws, too.

We used it at the beginning and every 10 shots we had to lean the hole spud gun. But worst case is, the deodorant doesn't ignite, then the hole greasy stuff sticks at the inside of your combustion chamber.
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rcman50166
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Tue Oct 06, 2009 9:07 am

Northir wrote:Whats the Best fuel for a standard combustion cannon, that you have found ive been using spray paint, it does not seem to work to well


(sorry about the original question)

Edited by jrrdw.
You may want to take a look at this. It was never finished, but maybe you can.
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