Vespel Alternative 1

[cbert]

I'm searching for a lower cost alternative to Vespel SP1.
Application is a poppet to seal a small orifice.
Temperature range is -65° F to 220 F, sealing air at 3000 psi. Not sure if PEEK or TORLON would be good down to -65?

 

[plastx]

IDES provides good plastics info. For VESPEL like materials go to:

http://www.ides.com/generics/TS/TS_products.htm

and look for "PI TS" and you can get some alternatives. IDES has some free info and other stuff is a $ service.

Mike

 

[israelkk]

I will not rush to replace Dupont Vespel SP1 without thorough checking if you have a good and long experience with Vespel SP1. We tried even Vespel SP1 from other sources licence by Dupont but it was not the same quality as DuPont's.

On an On-off electro-pneumatic valve that I designed and developed few years ago we seal up to 10000 psi of Argon and Helium with practically zero leakage.

We machine the seal from a vespel bar and as far as I recall the seal cost compared to the whole valve cost is negligible.

You should consider other things than the lower temperature. Each time the seal is pressed to the orifice the orifice creates a circular indentation in the seal. The indentation are not concentric and not at the same place every time. Where the circle indentation cut each other there is the source of leakage. If the sealing plastic is weaker than the vespel the indentation will be deeper and in time the valve will leak.

You may find that it may be very costly to save few bucks.

http://israelkk.googlepages.com/home

 

[plastx]

I agree that testing is critical to make sure that an alternate material doesn't ruin your product but I've been burned by only having one source of material. Do the math up front if cost reduction is the main purpose of the change to make sure the switch will yield greater returns long term.

Mike