What is the maximum pressure that a Schrader valve can be used in a pneumatic cannon?
IOW I would like to try a Schrader valve to fill the gun an also use it as the pilot valve.
My inspiration comes from this:
Will a Schrader take 600 psi?
BoyntonStu
Posted: Sun Sep 20, 2009 7:42 pm
by Mr.Sandman
Well i you can find it i believe there is a thread where gippeto has tested the valve core to 7500 psi. So i do believe it will take the pressure. I have personally used them to 1500 psi with no problems
Posted: Sun Sep 20, 2009 8:38 pm
by boyntonstu
Mr.Sandman wrote:Well i you can find it i believe there is a thread where gippeto has tested the valve core to 7500 psi. So i do believe it will take the pressure. I have personally used them to 1500 psi with no problems
What kind of chuck did you use?
Was it a no-leak or a conventional chuck?
BoyntonStu
Posted: Sun Sep 20, 2009 8:41 pm
by Mr.Sandman
boyntonstu wrote:
Mr.Sandman wrote:Well i you can find it i believe there is a thread where gippeto has tested the valve core to 7500 psi. So i do believe it will take the pressure. I have personally used them to 1500 psi with no problems
What kind of chuck did you use?
Was it a no-leak or a conventional chuck?
BoyntonStu
I used this ancient schrader adapter i found in my dads tool box. Rated to 3000 psi is engraved into it.
Posted: Sun Sep 20, 2009 8:44 pm
by boyntonstu
Mr.Sandman wrote:
boyntonstu wrote:
Mr.Sandman wrote:Well i you can find it i believe there is a thread where gippeto has tested the valve core to 7500 psi. So i do believe it will take the pressure. I have personally used them to 1500 psi with no problems
What kind of chuck did you use?
Was it a no-leak or a conventional chuck?
BoyntonStu
I used this ancient schrader adapter i found in my dads tool box. Rated to 3000 psi is engraved into it.
Did you hold it against the valve at 1,000 psi or was it connected?
Posted: Sun Sep 20, 2009 8:57 pm
by Crna Legija
600psi wont brake the valve.
Posted: Mon Sep 21, 2009 12:54 am
by Gippeto
Yeah, tested to 10000psi actually. Destroyed the sealing face of the core, but no other damage. Replaced the core and it's in use today.
I've used a schrader as a pilot on a 1" piston but you need to have an efficient design with a tight piston and limited piston movement to ensure minimum pilot volume. Of course if your design has an airtight piston that greatly increases your chances of success.
Posted: Mon Sep 21, 2009 8:33 am
by boyntonstu
Gippeto wrote:Yeah, tested to 10000psi actually. Destroyed the sealing face of the core, but no other damage. Replaced the core and it's in use today.
I am afraid that if I do away with the ball valve the Schrader may leak when I remove the chuck and accidentally fire the cannon.
BoyntonStu
Posted: Mon Sep 21, 2009 8:44 am
by boyntonstu
jackssmirkingrevenge wrote:I've used a schrader as a pilot on a 1" piston but you need to have an efficient design with a tight piston and limited piston movement to ensure minimum pilot volume. Of course if your design has an airtight piston that greatly increases your chances of success.
Great work.
You got there before me, wonderful!
Have you thought of a trigger mechanism to press the Schrader?
Bravo!
BoyntonStu
Posted: Mon Sep 21, 2009 8:53 am
by Crna Legija
I have got 300psi with a but i had to push it keep it on.i use QD now its ezyer. Air you using co2 or air.
Posted: Mon Sep 21, 2009 9:04 am
by jackssmirkingrevenge
boyntonstu wrote:Have you thought of a trigger mechanism to press the Schrader?
Usually the first bolt/screwdriver/allen key I find lying around
Closest I made to an actual "trigger" was on the original pen gun.
Re: Schrader pressure limit?
Posted: Mon Sep 21, 2009 9:24 am
by rcman50166
boyntonstu wrote:What is the maximum pressure that a Schrader valve can be used in a pneumatic cannon?
IOW I would like to try a Schrader valve to fill the gun an also use it as the pilot valve.
Stu, I have tried a couple of those "clip on" style chucks. They blow off at ~250psi. I use only probe style fills and threaded connections with check valves now. Trouble free.
Another option is these fittings used on many pcps. They have the check valve built in. For lower pressures, I'm sure you can figure how to make one from a common compressor fitting?
The fitting I linked you to previously, does not open the valve, rather the incoming pressure must overcome the spring on the schrader. This means that when you stop pumping and go to remove the fitting, the schrader is already closed and won't leak.
The downside, is that you need to generate the extra 70psi to crack the schrader open.
Posted: Mon Sep 21, 2009 2:50 pm
by jackssmirkingrevenge
Gippeto wrote:The downside, is that you need to generate the extra 70psi to crack the schrader open.