first piston

[inonickname]

also the rubber is very tough i took a big sample and tried stabbing it a few times, like i said very tough outer rubber

Now stab it with 491 pounds of force.

[colty-bear]

ok i was shooting again this morning and i think im in the clear i shot of 70 rounds and not even a slight leak but i got a cheap 1$ shrader core that i screwed into a 1/8 bushing to 1/4(it was 1/8 because it was supposed to go into a shrader base on the tire so the threads did not match up but it didnt leak at the threads) but after i took it to 150psi after about 50 shots it started leaken real bad then i read the package "120 psi max working pressure"
Anybody know where i can get a high pressure shrader that will hold 400 or above? and have 1/4 or 1/8 threads?
spud tech and launchpotatoes both have 1/8 and 1/4 threaded ones but the do not say max pressure.

[CpTn_lAw]

You could have soldered something like a washer on the inside edge of the barrel. that would have solved many problems, from air leakage to neoprene cutting.

[colty-bear]

well i think i have all that figured out now but back to the shrader valve crisis ha

[mark.f]

Simple rubber schrader valves that go into car tires can be used at pretty high pressures. Jack simply removes the rubber from the stem and epoxies them into his projects.

[colty-bear]

what holds more rubber or metal? metal would be easier just teflon tape and screw in

[mark.f]

Well, you can get metal valves from suppliers like McMaster which will hold more than the thinner rubber-encased stems, at the expense of shipping and price.

[colty-bear]

i see the stainless steel ones hold 3000 psi but i can understand what connection it is but i need 1/8 npt or 1/4 npt
http://www.mcmaster.com/#schrader-valves/=2sd30h

[jrrdw]

the rubber i am using now is tractor tire rubber VERY HARD and seals up it wont stamp because it has wire running inside it to reinforce it.

The worlds 1st steel belted barrel seal, I love it.

[mark.f]

Brass and nickel plated are rated to 200 PSI, but would most probably be fine at around 400 PSI, although there's no real telling as I haven't an example of anybody using them like that.

Stainless steel ones for shocks, cylinders, springs, etc., are rated to 3,000 PSI, and would more than work well enough for whatever you're doing.

[colty-bear]

FIXED! damage pics and things soon! i looked around and found my old potato cannon (dwv scrapped) and the valve on that had a removable core works good shot 100 shots no leak but its worth it is was 10.00 at a gas tire station

[inonickname]

You will find the stainless steel schrader valves from mcmaster have a metric thread.

Good work on getting it fixed anyways