oring o-ring seal material nitrile viton teflon

[oldcorollas]

/\ keywords so i can find later

here is a nice description of different seal materials and temperature ranges...
there is another, but i can't remember where it is...

http://www.pspglobal.com/low-temperature-seals.html

Materials & Temperature
Applications
Use With These Fluids

Aegis®
-30°C to 232°C
*reg. TM International Seal Co. Aegis® oil seals are molded of an elastomer that has the broadest chemical resistance of any elastomeric material. They combine all the resilience and sealing force of an elastomer with a chemical resistance approaching that of Teflon. most chemicals

Aflas®
-30°C to 204°C
*reg. TM Asahi Glass Co. Aflas® oil seals are made from a unique fluoroelastomer that is resistant to petroleum oils, steam, hydrogen sulfide and amine corrosion inhibitors. petroleum oils, H2S, steam

Carboxilated Nitrile
-54°C to 135°C Nitrile oil seals are made from a compound that toleratres low temperatures and has excellent abrasion resistance. petroleum oils, water

DuPont Dow Viton®
-30°C to 240°C Viton® oil seals feature excellent resistance to petroleum products and solvents. They have good high temperature and low compression set characteristics. They are suited for use with wide chemical exposure situations and for hard vacuum service. petroleum oils, gasoline, transmission fluid

Fluorosilicone
-56°C to 204°C A fluorosilicone oil seal combines the good high and low temperature stability of silicone with the fuel, oil, and solvent resistance of fluorocarbon. This oil seal is resistant to petroleum oils and gasoline. petroleum oils, gasoline

Highly Saturated Nitrile (HSN, HNBR)
-26°C to 160°C Oil seals made from highly saturated nitrile have excellent resistance to petroleum oils and sour gas. Because of the extended temperature range of highly saturated nitrile, it is becoming a preferred compound in the oil patch. petroleum oils, H2S, CO2

Nitrile (Buna-N)
-40°C to 135°C
Nitrile (Low-Temp)
-65°C to 120°C Nilrile is presently the seal industry's most widely used elastomer. Nitrile oil seals combine excellent resistance to petroleum based oils and fuels, silicone greases, hydraulic fluids, water and alcohols. Nitrile has a good balance of working properties such as low compression set, high tensile strength, high abrasion resistance, combined with a low cost. petroleum oils,
water, hydraulic oils

Polyurethane
-40°C to 105°C Polyurethane is an excellent material with high abrasion resistance characteristics and high tensile strength. Polyurethane oil seals are used in high pressure hydraulic systems where highly stressed parts are subject to wear. These seals are resistant to petroleum oils and hydraulic oils. petroleum oils,
hydraulic oils

Teflon
-20°C to 204°C Teflon is a tough, chemically inert polymer possessing an incredible working range. Oil seals from this material are for static and slow intermittent dynamic situations. Teflon is hampered by a poor memory at low temperature. most chemicals
Polyacrylate
-20°C to 170°C Polyacrylate has better heat resistance than Nitrile. It works well in high surface speed oil seals. petroleum oils, Freon

Silicone
-60°C to 200°C Silicone oil seals have a high lubricant absorbency which minimizes friction and wear. petroleum oils, some acids

[roadsailing]

so short version:

use dupont VITON for everything but teflon should be fine

oh yeah, Polyacrylate could use an enter key before it

[oldcorollas]

Viton is the shizzle, and easily available (will cost say.. $2 instead of 30c for a nitrile, but it won't harden like EVERY nitrile rubber seal does on every engine....)

silicon is also good, but is softer, whereas viton is harder (more like nitrile) so you might need to change the dpeth of grooves for different o-ring materials (ie.. for soft silicon)