Funny this topic came up. I was almost about to post a thread asking why you don't see many diaphragm guns these days. Way ahead of ya! :wink: http://www.spudfiles.com/forums/homemade-diaphragm-valves-t18496.html I've been using a bike tube with a washer bolted on the center so it holds up to press...

That looks beautiful! If you know the MASS of the propane in your tank, you can probably find the moles of propane, thereby finding the total amount of propane you have. Using the ideal gas law you can probably find the total number of shots you can get. I think this'll work, but there are also addi...

I might be a bit worried about the swingy thing hitting too hard inside the valve. Other than that the idea sounds pretty good...How do you plan on attaching the spring to the flap?

I'd second the DDT theory. So does figure 6.7 in the link. http://www.spudfiles.com/forums/first-hybrid-with-videos-t18493.html If you plan on continuing to use such a long barrel on such high mixes, maybe a copper barrel would actually be a better option? If copper bursts under detonation, it's mor...

Small electrical pumps that are meant to dish out high pressures into tires usually fail; they burn out under the heavy volume of air spudding requires.
I doubt the fish pump will be able to do much better.

What I meant with the piston valve being inconsistent is just my own experience. I've always had problems with pistons getting jammed or not sealing properly, which has mostly been due to ill construction. I have a bad record with piston valves... So diaphragm valves are inconviniently sized. Is the...

So piston valves seem to be current standard of high quality spudding, and for good reasons. However, we don't see that many diaphragm valves, even though they're very similar to piston valves and probably easier to build. Why is this? The reason I ask is this: I'm making a paintball gun that's hook...

Thanks Jonnyboy! I do have to use a regulator like this though; the meter I hope to operate using sprinkler valves and batteries to provide the cannon with a high rate of fire. The flow adjustor would require that I monitor the meter pipe’s pressure, which will lower ROF.

Oh...I see...
Well, with a little more searching, I found this, which is more expensive, but looks right:
-Link changed, PCGUY http://tinyurl.com/8rhoh3

Better?

I don't know why, but the text didn't show up when I looked at this thread???

Hello! So I'm looking to build a propane/air meter for an upcoming hybrid cannon. It's going to require two regulators (one for air, one for propane) but the thing is is that if I were to get two regulators at lowes or Home Depot, it'd cost 40 USD plus Tax, which is pretty big for me. So I was searc...

@ ALIHISGREAT: Yeah, looking at the search results, hybrid coaxials have bad expected preformance. However, I think I might try it anyways; I'm more concerned with the ROF of the system than the energy. For now I think I'll go with the diahphragm for simplicity, but if I try to improve the system, I...

Cheeseboy, I'd chek out the rating of your sprinkler valve first; my standard Rainbird ones are only rated to 125psi. Not to be the saftey nerd, but remember that PVC isn't made to handle air pressure; it's built for water. So theoretically, unless you're using water as your pressurizing fluid, you'...

Thanks for the help! I've decided I'm going to use a diaphragm valve as recommended. I made a diagram below. I'm thinking of making it in a 1" steel T, A couple questions though: 1). Do you guys think that 4 layers of bike tube will be okay as the diaphragm? 2). Is a washer necessary? I don't plan o...

Okay, so the barrel/lip will be made of 1/2" copper type L, and the piston carriage will be 3/4" type M copper. They'll be put together in a 3/4"copper T, and will connect to a smallish chamber, probably 12" of 1-1/4" Galvanized steel. The piston housing is 5" long, with about 2.5" of a steel elbow ...

Hello friends! It’s winter break for me, and so I’ve decided to make a new cannon; a hybrid piston-valve cannon. This is mostly an experimental cannon; it uses a hybrid piston valve I’ve “designed” as well as a bolt system that I think is new (but not revolutionary). So I thought I’d pass it by you ...