Sun? It barely shines in England!

It's only holding back 170psi or so.

The 750psi version will be turned Al with screw threads & neoprene O ring seals (made properly!). It will also be a lot smaller - about the right size for paint-ball pellets & peporami sausages

Si

Hot glue is marvelous!

[for sealing tiny holes at least]

It was surprising with the one above with all the parts accuratly machined and properly secured, just how much deformation there was at higher pressures and how much air can leak out of a gap as small as a couple of thou.

Trouble with it ...

At 20 deg C, the vapour pressure of CO2 is about 750 psi. You can only get it to go higher if you heat it.

The rest of the gun will be machined out of Aluminium with sufficient wall thickness to survive 2000psi. Prior to use it will be proofed by pressurising it with hydraulic oil (less exciting if ...

I tested such a valve - and it took 60psi to force it to open - which is probably too much.

I'll instead just use a ball-bearing in a counter-bored hole in the piston.

However, I still want to use a pair of schrader valves, one to hold the gas pressure inside the container the sparklet bulb screw ...

I've had a reasonable amount of experience building piston & similar type valves.
http://www.x-eng.co.uk/images/spud/cannon1.jpg
What I'm planning is something which operates using full pressure (750 psi or so) Carbon Dioxide.

Although it is certainly possible, it's hard to prevent liquid CO2 ...

I had hoped, with enough pressure, it would act as a check valve without pressing the pin?

Si

Anyone know that the thread size is for the bore the schrader insert screws in to is?

I found a reference to the size of the outer stem of a cycle/car valve, but I would prefer to make the whole thing!

I have a plan for a small CoAx gun, using full pressure CO2. It uses a piston type valve with ...

Thought I'd introduce myself (as a newbie, least on here) by showing you my air cannon......
http://www.x-eng.co.uk/images/spud/cannon1.jpg
As you can see it's a co-axial barrel/reservoir design with a piston type valve.
It's built from 3" and 1.5" thin wall stainless tube made for pressurised ...