SpudFiles

How exactly did you make your piston? You said 2 disks of alluminum foil.

you take the valve apart

the tyre valve is for tubeless car tyres and i epoxyed in it there so it wont pop out i've had it up to 120psi and it was working all fine.

the piston is made originally out of 2 discs of aluminium sheet 2mm thick not foil with a spacer in between it but after afew shots the aluminium shit itself and bent as it flew backwards when i shot the cannon so i had to make a new piston this time out of titanium which doesn't bend at all and its been working great ever since

I am also wondering about the piston... You said it was made out of titanium? What material do you use to seal the barrel? Can you sketch a little pic of your piston.. im new to pistons... i made one tonight that slowly leaks into barrel... help would be greatly appreciated.

Pistons are a tricky thing to get used to making. Try a little dish soap where the rubber sels the barrel.

You can buy Schrader that are a rubber foot for the base (like a flange) that seals rather well. Try autozone or a local equivalent.

i'm new to this stuff all together and if i understand right, you don't make all Pneumatcs with pistons, right?

Cause i was gonna make a basic one with a pressure chamber and a moded sprinkler valve. Which i assume should work fine.

When you glue the chamber and the other bits, whats the Best stuff to use?

you are correct, not all pneumatics use pistons. that's just one option. a piston is good because it is simple and cheap, and i allows very high ariflow with good opening speed. I have made both piston cannons and smaller guns with just a pressure chamber and a modded sprinkler valve, this works very well on small diameter pipe, up to about one inch diameter or maybe a little bigger, but after that the sprinkler valve constricts the airflow and reduces power. a coaxial piston or diaphragm cannon is best for larger barrels. really, you could put any type of valve you wanted between a pressure chamber and a barrel, but some valves, such as ball valves, are slow opening.

when gluing the chamber and other bits, by stuff i assume you mean glue. you need to use pvc cement and primer. do a little research if you are unsure about using it.

If you mean the pipe, then use pressure rated schedule 40 pvc, and avoid DWV fitings. make sure everything says NSF-pw.

How did you seal the barrel where it comes out of that end cap?

how does that sprinkler valve work on the tank like that why doesnt the pressure just go out the barrel? maybe i saw somethin wrong but i dont get that

patraccoon, if you cement it properly, it should seal.
tater36, it's a basic coaxial piston valved gun, do some research.

man i realy like that gun, i especialy like seeing stainless steel you must have the same tube as what i have on mine cept mine is all stainless

Another question....

Does putting the fill valve (either tire-valve or Schrader valve) in the Sprinkler valve affect the integrity of the PSI rating?

On the Wiki and the forums in general my impression was the recommendation was to put the valve in the thickest part of the gun for safety?
If it does not affect the PSI -will putting a PSI Gauge there next to it weaken the plastic to much?

Very neat and very nice...I like the design and the look.

how did you seal the barrell to the cap