Which valve?

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.
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deathbyDWV
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Sun Jan 17, 2010 12:49 am

Alright guys...

So for my birthday this year (money time) I was thinking of building a monsterous cannon... Similar to joel's tornado simulator and mobile chernoble's (i think he made it... Correct me if I'm wrong) +10 gallon cannon.

It would have two 6 inch by 4 foot chambers and a 3 inch by ten foot barrel.

My question is... What would be better, a 4 inch piston valve or two of launch potatos mauler valves?

I was guessing, because of it's size, the piston would be better since it would have a bigger outlet but open slower.

I was also looking towards two maulers because they would fit my design better. They also might make up the difference and be more powerful too.

Tell me what you think. Or does anybody know for sure?
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hi
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Sun Jan 17, 2010 1:17 am

I don't know for sure, but in going to say that a single piston valve would be more powerful.

I built a massive cannon once and used a piston valve. I didn't use a bumper and the piston was solid wood with a bolt through it. the cannon fired 5 or 6 times, then the valve blew up in my face. I'm lucky I didn't have any PVC chunks hit me, that would be a ticket to the hospital, so be careful. I would recommend operating the valve from a distance with a string or something. it sounds stupid, I know, but it can be dangerous.
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deathbyDWV
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Sun Jan 17, 2010 1:30 am

Yes I realize how much force is involved. I once had a cannon with a two foot by 4 inch chamber and the reducer on the end with a gauge bal valve and quick connect blow off at 60 psi. It flew a good 60 feet and bent and ruined the guage. This was also after many test fires. The force was great enough to blow the cannon out of my hands...

Back on topic...

I also more wanted to use maulers because if I ever get bored of the cannon I can take it apart and use them for something else...
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MrCrowley
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Sun Jan 17, 2010 3:43 am

The two Maulers will have more flow and will open faster and be more efficient than if you built your own valve. So performance wise, go with them. They'll cost a fair bit though. If you really want to harness all this power, go with a 10' barrel. Longer the better.
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jhalek90
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Sun Jan 17, 2010 11:05 am

and where are u getting 6'' pvc and fittings??

Sounds like your going to spend upwards of $500 usd

I would suggest building a smaller... steel gun... to run at higher pressures... and get close to the same performance.
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deathbyDWV
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Sun Jan 17, 2010 11:21 am

Thanks MrCrowley. I'm guessing you're right considering you usually are. :D

That is probably what I'll go with.

I can get fittings at a local place called water products. I will either get them there or on McMaster, depending on which is cheaper.
pyrogeek
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Mon Jan 18, 2010 1:29 am

You could always find an old CO2/nitrous tank or something and build a hybrid. Or use CO2 as a propellant. With a higher pressure you could use a smaller valve and still get the same amount of gas flowing to propel the "potato".

PVC is just ungodly expensive when you get to dealing with larger stuff. Just go metal and it will handle more pressure and won't have to worry about it getting brittle...at least for your purpose.

If you're contemplating dual valves or one good one. Just get the one good one. It's just easier, just make sure it's plenty big and fire smaller projectiles.
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deathbyDWV
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Mon Jan 18, 2010 11:02 am

I realize that PVC is really expensive for some, but to get a large metal tank (or two) AND a higher pressure system would be even more expensive.

Also I'm already working on a hybrid... :D

... Just got my oxy mapp setup...
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