Fuel

[rebalgray]

What gives the largest flame and the loudest bang?

Martin

[imjustpk]

well there are a lot of variables to that question, instead of going for a more powerful and dangerous fuel you might want to experiment with chamber to barrel ratios

[chaos]

Well i find with my combustion http://www.spudfiles.com/forums/viewtopic.php?t=5919&
i get a really sharp crack when i use brut24hr(black can) deodorant but as for power i do not not for it was dark and i could not see the golf ball.
i also find that camping gas for portable bbq's with a 80%butane an 20%propane give quie alot of power and a large bang upon firing

peace

[Recruit]

What gives the largest flame and the loudest bang?

Martin

A. C4
B. H-bomb



Seriously there is no specific best fuel. Their is on experimentation.

[rebalgray]

I have a 4" X 11" chamber with two different barrels. One is 1.5" X 3' The other one is 1.25" by 3'. I'm not looking for power just a bang and a lot of flame. It has metered propane on it now. I haven't fired it yet. I'm still putting it together.

Martin

[LGM]

For flame use a bit too much gasoline, make sure that you still have enough to fire it though. Propane gives a nice jet of blue flame at night, but not a fireball. If you just want flame and don't need to shoot something, spray WD-40 down the barrel, meter the propane, and watch the flames.

[rebalgray]

Thanks for the help. I'll give it a try. Right now i'm scaring the hell out of the dogs with my pill bottle mini.....lol....

[meatballs]

one thing that gives a good fireball is if you put two layers of plastic wrap over the end of the chamber with a half cup or so of alcohol between them. fuel the cannon as usual, and the blast both vaporizes and ignites the alcohol. it makes a good fireball, three to four feet across, a bit larger than an exercise ball. its awesome. i haven't tried it yet, but gasoline would work too. it has similar properties to alcohol (like volatility) but the same amount has more energy so the same amount should give a bigger fireball.

[Pete Zaria]

A few things:

1) Big muzzle flashes usually indicate an inefficiently high C:B ratio, or a much-too-rich fuel-air mixture.

2) Spraying anything down the inside of the barrel is a bad idea because it will continue to burn for a few seconds after the combustion process is over, and will gradually weaken the barrel. I've seen it happen.

3) Gasoline and PVC don't mix as far as I know. Since gasoline dissolves lots of polystyrene and polyvinyl products, I try to keep them separate, lol. It should be OK in ABS though...

4) Meatballs has it right, the best way to do special-effects type fireballs is by putting some fuel at the END of the barrel. I've done this by putting some paper towels soaked in alcohol or diesel in the end of the barrel (though I use ABS for my combustion guns so I don't worry much about the effects of solvents on the pipe). That works great. I'm sure his plastic wrap idea would be fine, too.

5) Loud bangs are best accomplished using burst disks and a short barrel. Propane is very loud when mixed properly. Engine starter fluid (usually contains ether) is the next best thing if you can't do metered propane.

Peace,
Pete Zaria.

[paaiyan]

I've been wanting to experiment with powdered magnesium, but I'm not sure how easily it would ignite. If you could get it to work, you'd be rewarded with a very bright white muzzle flash. I mean blindingly bright, especially at night.

[Pete Zaria]

I've been wanting to experiment with powdered magnesium, but I'm not sure how easily it would ignite. If you could get it to work, you'd be rewarded with a very bright white muzzle flash. I mean blindingly bright, especially at night.

It would be a lot of fun to build a small special effects cannon with a small-ish (say, 2" x 10") steel chamber, a half inch union for burst disks, and a few inches of half inch steel pipe for barrel. Setup a small propane (and/or oxygen.... ) meter system.... You could load it with burst disks, put powdered magnesium, powdered iron oxide and aluminum, gas, whatever in the "barrel" and fire it. Having the combustion occur directly under the "secondary fuel" should ensure ignition. Especially using oxygen.

Wouldn't be too expensive either...

Peace,
Pete Zaria.

[paaiyan]

I've been wanting to experiment with powdered magnesium, but I'm not sure how easily it would ignite. If you could get it to work, you'd be rewarded with a very bright white muzzle flash. I mean blindingly bright, especially at night.

It would be a lot of fun to build a small special effects cannon with a small-ish (say, 2" x 10") steel chamber, a half inch union for burst disks, and a few inches of half inch steel pipe for barrel. Setup a small propane (and/or oxygen.... ) meter system.... You could load it with burst disks, put powdered magnesium, powdered iron oxide and aluminum, gas, whatever in the "barrel" and fire it. Having the combustion occur directly under the "secondary fuel" should ensure ignition. Especially using oxygen.

Wouldn't be too expensive either...

Peace,
Pete Zaria.

Yea that would be pretty sweet. Of course, being a half inch barrel you could also load marbles, just so it could also be functional.

[SpudBlaster15]

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