Propane Interchangeable 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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blindbatjosh121
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Fri Aug 01, 2008 8:06 am

This is my first canon post ever. Please no negative comments but constructive criticism is excepted. I no it’s not perfect but I gave it my all. I built this potato gun about a month ago and have not gotten up to putting it on spud files. I use it all the time however I never have a camera handy.

If any knows, could you explain to me how to make an image preview for my post?? Thanks

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Barrels: I have 8 interchangeable barrels from 1/2 " (pneumatic) all the way up to 4". (In below picture)

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Ignition: Grill sparker attached to two screws in chamber.

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Mixing/Exhaust: 12 volt computer fan on inside of chamber with toggle switch and batteries on outside.

Fuel: Coleman propane tank attached to PSI gauge and blow gun. (Propane at 40 PSI for 2 seconds into chamber)

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Chamber: 1 1/2 ft 4" chamber with cleanout plug (in case of any problems on fan or spark). On the other side is a 2 " female adapter for barrels.

So far I have no damage pictures but I sure do have great damage and destruction! I have a recorded distance for an orange over 300 yards on my 3” barrel. On 5 shots I tried measuring at our farm I lost site of the ammo which were limes, oranges, and ripe acorns. The average lime traveled a distance of over 400 yards!!!!! It surprised me when the heavier items flew farther but then again an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

I worked very hard on this project and to me the cost, labor, and problems throughout it have completely themselves off.

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Last edited by blindbatjosh121 on Sat Aug 02, 2008 5:52 pm, edited 1 time in total.
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jrrdw
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Fri Aug 01, 2008 3:01 pm

Welcome to Spudfiles.

Nice cannon you built. It's a advanced combustion for your first, thats good. Damage pics are allways welcome, so are video's if possible. You should upgrade your ignition to a stun gun or photo circuit.
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Coodude26
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Fri Aug 01, 2008 3:08 pm

That's a great cannon, especially for your first.

I'm not too familiar with propane injection, but I'm pretty sure if you used 2 valves instead of just the 1 blowgun valve, you could just open one, charge a tiny section of pipe to a certain pre-calculated pressure, close it, open the other, and dispense all of that into the chamber, so that way it would be harder to make an error.

Great job, but damage videos would be shweet :) :D
ThyReaper
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Fri Aug 01, 2008 8:50 pm

Whoa DUDE! That things beastly haha

Sucks u cant go dirt biking...But if u can ur bringing that to show my grandparents!!! Bet they'd love it haha
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starman
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Fri Aug 01, 2008 9:25 pm

blindbatjosh121 wrote: If any knows, could you explain to me how to make an image preview for my post?? Thanks

I worked very hard on this project and to me the cost, labor, and problems throughout it have completely themselves off.
You're using the wrong link imageshack gives you.... use the link labeled "Direct". The forum software will size it for preview here.

I can tell you have put some effort into this gun, the best feature being your interchangable barrel system and hose covered hose clamps. It looks like you've got your fuel "spraying" down pat...basically only replacing the hairspray can with propane. However, it could be better with a real fuel meter of some sort on there. You still have to open the cleanout to air it out...a ball valve could simplify that as well. And finally, the green camping propane bottles are a little bulky to attach to your gun, the blue 14 oz tanks are less bulky and somewhat easier to mount with your chamber.


Nice first cannon however. It wouldn't take but a couple of things to make it first rate!
1se7an
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Mon Aug 04, 2008 5:04 pm

You need to put a stengun on that puppy!
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blindbatjosh121
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Mon Aug 04, 2008 9:15 pm

1se7an wrote:You need to put a stengun on that puppy!
O ya I plan on putting a stun gun on it. I wont get a stengun (lol) because they are a little to expensive for me but a stungun will be perfect.
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