Help with a first pneumatic gun

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
TheHumbleMuffin
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Wed Mar 07, 2007 8:08 pm

Hi, I've been planning to construct my first pneumatic spud cannon. I've been looking for advice on a trigger mechanism. I've looked at many, and they have modified sprinkler valves as a mechanism. I was wondering if that was a)simple and b) cheap to do... If so, would it be a good idea to use something like a ball valve instead?



Also, somewhat off topic, I also want to build a good combustion gun. What is your advice on chamber fans? I've built a combustion gun before, but it was your basic, run-of-the-mill gun...BBQ lighter ignition, 4"x2' chamber, 2"x4' barrel.
*Note: Engine starting fluid in a spraycan containing diethyl ether is a GREAT propellant.
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Pete Zaria
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Wed Mar 07, 2007 8:20 pm

@TheHumbleMuffin

Sorry dude, you need to search the forum more before you post. The answers to ALL the questions you asked have been asked here lots of times before, and are available to you. Look around.

I'll spoonfeed you a bit:

Valves, in order of performance, best to worst, IN MY OPINION. There are variables. Assuming equal size....
Piston valve (home made)> QEV (Quick Exhaust Valves, these are hard to find bigger than 3/4") > modified sprinkler > unmodified sprinkler > ball valve.

Faster (lower) opening time = better performance.

A 1-1.5" sprinkler valve should cost no more than $15. A blowgun, some hose, and a hose barb should be another $15 tops, so around $30 for a completed unit.
A piston valve is harder to build but yields greater performance. You need some mechanical/technical skill and patience to build one though.

Chamber fans are a must for a good combustion gun.

Again, look around!!! Check out the How-To section, I wrote two guides on combustion guns, which address propane meters, chamber fans, spark strips, etc.... The Wiki link at the top of the page also addresses these issues (both the sprinkler valve and chamber fan)!

Sorry to be harsh. You're the 4th or 5th "first-poster" today that I've had to tell to search before they post. I don't mean to be bitchy.

Peace,
Pete Zaria.
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Legendpilot
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Wed Mar 07, 2007 8:27 pm

Personally I like this type of trigger mechanism. Make a diaphragm valve using a 2" tee and trigger it with that blowgun. It works very well for me. -Lp
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pyromaniac
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Thu Mar 08, 2007 8:40 pm

It depends on your budget. IF you have enough to get a sprinkler do so. if not you can also get a ball valve until you get enough money to get the sprinkler.
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spudthug
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Thu Mar 08, 2007 9:25 pm

as pyro says it depends on your budget some ball valves cost around 5 bucks...some sprinkler valves cost around 15-20 bucks...and if your going to use a sprinkler valve use a modified they are just lkike a ball valve un modded...maybe i little faster but not much...so i would use a sprinkler valve for ur first...if your budget is high buy a mauler or a supah for a sort of big gun but they are around 90-100 bucks...
itwentboom
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Thu Mar 08, 2007 9:38 pm

If you can't afford it don't build it. If you build one now and wanted to upgrade it later, you will be spending twice the amount of money.
allthingsgo2
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Sun Mar 25, 2007 1:56 am

I used a standard fluid master inline valve thats a three quarter inch diameter for my paintball marble "sniper" of sorts. with a small on off switch on the side below the solenoid that is a open close switch that just takes a thumb flick to open instantly that should be available at your local homedepot place. for under 10 bucks

Good Luck and happy shooting

Colin
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Fri Apr 06, 2007 9:28 pm

you can get good releases with ball valves if you modify the handle a little bit. I have seen extensions on the handle to drop the valve quicker. it works well.
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tater36
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Fri Apr 06, 2007 9:40 pm

give me an example of a modified ball valve handle cause i want to do that if it goes faster, cause i got a nice ball valve 1/2 barrel gun that shoots carrots and such and id like it to release faster (im savin money for a sprinkler valve for my next big one)
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