PCP's Valves

[SCW22]

I've picked a gun up this week(not on here) and the Vavle stem is bent and the cap on the end is damaged.

As my old man is an engineering machinist we are going to make a new one.

I have some silver steel for the Valve stem but what is used for the sealing cap/valve head.

Is Ptfe ok.

thanks

steve.

[franktheferret]

Silver Steel is a great material but it is fairly soft and would not be a good thing to use for a "knock-open" valve stem unless it were correctly heat-treated. Silver Steel is also very prone to rust, and that would not make for a good seal, over time. PTFE makes a very good seal material, but its non-slip properties make it very difficult to machine to a surface finish suitable for high-pressure seals. I'm not trying to pass water on your fireworks, but it might be better to get a new valve and enjoy your new rifle with confidence.

Good luck,

Alan.

[SCW22]

As far as i was aware most valve stems are made from silver steel as it is made from tool grade material for making things like punches and drifts?

Also we are talking about working with a highly skilled engineer who has more than a hobby lathe and 45 years exp.

if you would no use silver steel or Ptfe what would you use?

Thanks

Steve.

[Jonathan]

Silver steel's fine for the knock open valve - but you could also use stainless. As for the valve, use Acetal. It's an absolute delight to machine and has all the properties required to do the job well.

Jonathan.