PTFE vs EPDM 2

[trixvalve]

Could someone teach me which is the best material to be selected for seawater at 15 barg and 60 degrees? Is there any advantage using PTFE instead of EPDM? How about durability? Thanks

 

[btrueblood]

Depends on your application, what are you trying to do?

EPDM is softer and makes a better sealing material (conforms better to rough surface finishes). Teflon is stiffer and slicker, which might hold up better in a dynamic or abrasive application. Both could care less about sea water from a chemical attack/corrosion standpoint.

 

[GrahamBennett]

I agree with btrueblood, either would be good depending on the application. Are you talking about 60°C or 60°F water temperature? Even at 60°C, natural rubber would be suitable too (and has the added advantage of being a sustainable resource and relatively easily recycled at the end of the part's life).

 

[MJFH]

Have you considered Gore-tex? It is an expanded PTFE, with an amazing chemical resistance. The only substance it will not support are rare alkalide metals or temperatures over 500f. At that temperature the PTFE will evaporate into fluorine gas. Also, the material is very resistant to abrasive material. It is a very clean material to work with and comes in a wide variety of styles. My favorite being the joint sealant. Just don't let the price turn you off from it.....

http://www.gore.com

 

[GrahamBennett]

The decomposition temperature of PTFE is >490°C (>910°F) and the main decomposition products are hydrogen flouride gas (extremely corrosive) and carbon dioxide. It is unsuitable for use where it will come into contact with acetone or hot alkaline applications.

 

[Kuzmicnr]

Btrueblood gives an excellent response, id give the same advice.

If you want the parts to seal use EPDM or Natural rubber, the PTFE material will not seal well at all. It is harder, yet more durable & certainly more costly but it most likely will not seal as well as an elastomer

Hope this helps confirm the previous post!


Nick Kuzmick
Timco Rubber Products
Cleveland OH

http://www.timcorubber.com