Compounds
Choosing the Right O-Ring Compound
A three-question shortcut to narrowing down the elastomer you need.
Aflas® (FEPM / TFE-P) O-Rings
Aflas® (FEPM, TFE/P) O-Ring guide: why less fluorine than FKM makes it the answer for steam, hot water, amines, strong bases, and sour gas, plus temperature range, grades, limitations, and the sizes we stock.
Butyl (IIR) O-Rings
Butyl (IIR) O-Ring guide: the lowest gas and water vapor permeability of the common seal elastomers, plus temperature range, chlorobutyl and bromobutyl grades, limitations, and honest advice on when EPDM is the better buy.
O-Ring Material Selection Guide
O-Ring compound selection guide with temperature ranges, shelf life, stocked inch and metric sizes, and where each compound belongs.
EPDM O-Rings
EPDM O-Ring guide: water, steam, brake fluid and weather resistance, -65°F to +300°F range, cure systems, durometers, the oil limitation, and the FDA, NSF-61 and peroxide-cured grades we stock.
FFKM (Simriz® Perfluoroelastomer) O-Rings
FFKM (Simriz®) O-Ring guide: temperature range, near-universal chemical resistance, honest limitations, standards, and every Freudenberg Simriz® compound we carry with what each grade is built for.
Fluorosilicone (FVMQ) O-Rings
Fluorosilicone (FVMQ) O-Ring guide: the fuel-resistant silicone. Temperature range, M25988 mil-spec grades, limitations, chemical compatibility, and the grades we stock.
HNBR (Hydrogenated Nitrile / HSN) O-Rings
HNBR (hydrogenated nitrile, HSN) O-Ring guide: temperature range, refrigerant and sour-gas resistance, cure systems, durometers, limitations, and the grades we stock.
Neoprene (CR / Chloroprene) O-Rings
Neoprene (CR, chloroprene) O-Ring guide: temperature range, refrigerant and ammonia service, flame resistance, aniline point, grades, limitations, and the sizes we stock.
Nitrile (Buna-N / NBR) O-Rings
Nitrile (Buna-N, NBR) O-Ring guide: temperature range, ACN content and what it changes, oil and fuel resistance, durometers, mil-spec grades, limitations, and everything we stock.
PTFE (Teflon®) O-Rings
PTFE (Teflon®) O-Ring guide: near-universal chemical resistance from -100°F to +500°F, why PTFE is a thermoplastic and not an elastomer, cold flow and gland design, filled grades, and back-up rings.
PTFE Encapsulated O-Rings
PTFE encapsulated O-Ring guide: a seamless PTFE, FEP, or PFA jacket over a silicone, FKM, or EPDM core. Temperature ranges, chemical resistance, limitations, installation, and the sizes we stock.
Silicone (VMQ) O-Rings
Silicone (VMQ) O-Ring guide: -75°F to +400°F range, the silicon-oxygen backbone, FDA food and USP Class VI medical grades, gas permeability, and why silicone belongs in static seals only.
Cast Urethane (Disogrin®) O-Rings
Cast polyurethane (Disogrin®) O-Ring guide: the best abrasion, tensile, and extrusion resistance of any common O-Ring material, plus the hydrolysis limit that decides where it belongs.
Millable Urethane (EU) O-Rings
Millable polyurethane (EU) O-Ring guide: temperature range, abrasion and tensile strength, low gas permeability, hydrolysis resistance, limitations, and the grades we stock for air guns, paintball markers, and pneumatics.
Viton® / FKM (Fluoroelastomer) O-Rings
Viton® / FKM O-Ring guide: heat to +400°F, fuel and chemical resistance, the honest low-temperature story, cure systems, fluorine content, durometers, mil-spec, FDA, and every FKM grade we stock.
Viton® Extreme ETP O-Rings
Viton® Extreme ETP O-Ring guide: the specialty FKM that survives bases, amines, ketones, and esters. Temperature range, limitations, grades, and where it beats FKM and undercuts FFKM.
