SpudFiles

Hi,

I'm glad to become a part of this forum. Seem's like there's more than enough very usefull information here, so that's great. Anyway, to my question. Lately I've been thinking of making a gun, probably with airsoft ammo, but with a valve from a paintball marker. Now I'm not sure of the specific type that uses this valve, but it's pretty much a copy of the one from the paintball gun, just a bit simplified. Now, I have no problems with making it , just with the material to use. I thought I could use a PVC rod and just drill the holes i need into it, but I'm not sure if it could hold the pressure. I would probably use those small 12 gram CO2 cartridges, because I think it's the easiest to get, maybe I'm wrong. So yeah, do you think that the PVC rod could hold the pressure? And what else could I use instead the CO2 cartidges? I'm attaching a picture of the valve and the approximate dimensions. Thanks (The vlave is really easy, a hammer powered by a spring hit's the valve pin and moves it backwards so that air passes by. A little ammount goes back through the hole by the pin and reloads the hammer back into place. Most of the air however traveles through the bigger hole that is cut out and goes towards the other side of the valve through grooves cut out right on the valve and that air shoots the ammo)

John

Pvc is too soft for 850 PSI of co2 and as co2 cools rapidly when released to the atmosphere the pvc will become brittle and shatter, you would be better with nylon or acetal and a stainless steel valve stem, just search pcp valve or hammer valve, an example is the valve i used on my gun in the thread "machined pcp" its all brass/steel construction and has a nylon sealing face, have fun

You could use a paintball tank instead of a co2 cartridge.

same design in the tippman 98 custom. extremely helpful diagram. However im not 100% sure how air is released from the front

Hi,

thanks for the replies. The problem with using other materials is that they're not sold in the shape i need them to be. I have no access to a lathe nor anything similar so the PVC was ideal because it's sold in cylinders and all I'd have to do is drill some holes and that would be all.

How much PSI do you think the PVC could hold? And when you say I could use a paintball tank, how would I refill it and also what kind of valve connection would there have to be?

John

well you would have to regulate the co2 to 300 psi

I've been reading through the net to find some information on the paintball air tank. I've found out that using a compressed air one could have a reducer for 250 PSI, which would be good. The only thing that sucks is that I'd have to get it filled somewhere and I'm not sure how far from where I live they fill it, but that's a detail. I am just a bit baffel up by one thing. They say that from a 4500 PSI compresed air tank you get about 800-1200 shot, obviously depending on the gun. What I don't understand is how can you get 1000 shots from 4500 PSI when you use about 100-200, maybe more, PSI per shot? When you divide 4500/200 you get about 20 shots. Could someone please explaion this to me? Thanks

Compressed gas shamefully doesn't work as simply as that I'm afraid, PSI isn't a measure of volume for gas, and the differences in volume of gas per cm3 in the gun and the atmosphere cause a gun to fire.
An easier way to think of it is the volume of gas used per shot, you can work this out by using boyles law: http://www.engineeringtoolbox.com/compr ... d_843.html - by working out the volume of gas needed for each shot you can then work out how many shots the tank can give you before the pressure would drop below the ideal pressure, (again by finding the total volume of gas in the chamber)
But after a while the maths can quite complicated, especially when trying to link in environmental factors. The easiest way is really by trial and error. When designing Paintball guns designers very rarely work out the exact amount of shots you could get with a tank because it varies so much with: temperature, size of chamber, and manufacturer defects and level of gun maintenance.
I hope that sort of answers your question