Silicone Gaskets.

What silicone is and where it fits

Silicone (specifically VMQ, vinyl-methyl silicone in its most common gasketing grade) is a polymer built on a backbone of alternating silicon and oxygen atoms instead of the carbon backbone most other elastomers run on. That structural difference is what gives it the two properties engineers specify it for. A wide continuous operating temperature range. Chemical inertness clean enough for food, medical, and pharmaceutical contact.

Silicone is the right call when either heat or cleanliness drives the spec. Food processing, medical devices, and laboratory equipment increasingly need both at the same time.

When silicone is the right call

• Extreme temperature range.Continuous service from -50°F to +500°F in standard grades. That's wider than any other common elastomer. Special grades push further in both directions.
• FDA food contact and USP Class VI medical. The default elastomer for FDA 21 CFR 177.2600-compliant gaskets, USP Class VI biocompatible medical devices, and NSF-51 food processing.
• UV, ozone, and weather inertness. Silicone is essentially untouched by outdoor exposure. Spec it alongside or instead of EPDM when both UV and heat are in play.
• Electrical / dielectric sealing. High dielectric strength and strong arc resistance make silicone the default for high-voltage enclosures, transformers, and electrical insulation gaskets.
• Low compression set under thermal cycling. Silicone holds sealing force better than most elastomers when a joint cycles between cold and hot repeatedly. Common in automotive cooling, HVAC ducts, and cooking appliances.

When silicone is the wrong call

• Fuel and solvent contact. Standard silicone swells in gasoline, diesel, jet fuel, and most hydrocarbon solvents. If fuel is involved, step up to Fluorosilicone (silicone's chemistry + FKM-like fuel resistance) or Viton^®.
• High mechanical abuse. Silicone has lower tensile strength and tear resistance than Nitrile or Polyurethane. For abrasive, high-wear applications specify Polyurethane or Nitrile.
• High bolt load / high seating stress. Silicone can extrude under sustained compression. For high-pressure flanges, specify Klingersil^® or non-asbestos fiber.
• Cost-sensitive commercial applications.Silicone typically runs 2–3× the cost of Nitrile or EPDM. Reserve it for applications where its properties are actually required.

Grades of silicone that matter for gasket selection

• Commercial-grade VMQ:the default. Good for most industrial gasketing from -50°F to +500°F.
• FDA-grade silicone: compliant with FDA 21 CFR 177.2600 for food contact. Choose this whenever the gasket touches consumables.
• USP Class VI medical silicone: biocompatible for medical devices, pharmaceutical manufacturing, and diagnostic equipment. Carries lot-traceability documentation.
• Fluorosilicone (FVMQ): silicone temperature range plus fuel and oil resistance. Standard in aerospace fuel systems. See Fluorosilicone gaskets.
• High-temperature silicone:specialty grades extending continuous service to +600°F for short-duration applications.
• Platinum-cured silicone: peroxide-cured silicone has residual cure byproducts that can leach; platinum-cured is the clean-room and medical choice.

Key specifications at a glance

These are the silicone properties Cannon Gasket specifies most often. For full durometer ranges, thicknesses, and certifications available in production, see the Silicone Rubber Gaskets product page.

• Continuous temperature range:-50°F to +500°F (-46°C to +260°C)
• Durometer: 20A to 80A Shore hardness (softer than most elastomers; 30A-50A is typical for food and medical sealing)
• Compression set: Low at high temperature; silicone outperforms most elastomers on long-duration thermal cycling
• Typical certifications: FDA 21 CFR 177.2600, USP Class VI, NSF-51, AMS 3304/3305, UL-157

Silicone vs. the alternatives

• EPDM. Cheaper, similar UV and ozone resistance, narrower temperature range (-70°F to +300°F), and without silicone's medical-grade options.
• Viton^®. Broader chemical resistance. Handles fuels and solvents silicone can't. Narrower temperature range.
• Fluorosilicone. Silicone's temperature range plus fuel resistance. Pick this when you need both.
• FDA / Medical-grade compounds. Silicone is the most common choice in this class, but EPDM, Nitrile, and Viton all have FDA-compliant variants.

Common silicone gasket applications

• Food and beverage processing equipment (FDA grade): oven gaskets, steamer seals, dairy fittings, beverage dispensers
• Medical and pharmaceutical (USP Class VI): diagnostic equipment, IV delivery systems, biotech manufacturing, surgical devices
• Appliance and cookware: oven door gaskets, pressure cooker seals, coffee equipment
• Aerospace wire harnesses and environmental seals where temperature range drives the spec
• Electronics enclosures needing dielectric sealing: transformers, LED luminaires, high-voltage connectors
• Automotive under-hood gaskets at elevated temperature (coolant, exhaust-adjacent assemblies)
• HVAC high-temperature ducting, boiler gaskets, steam trim

Manufacturing and sourcing from Cannon Gasket

Cannon Gasket has die-cut silicone gaskets for OEMs since 1971, with a dedicated clean-room setup (ISO 7 / Class 10,000) for FDA and USP Class VI production. We stock commercial VMQ, FDA-grade, and USP Class VI silicone in a range of durometers and thicknesses. Parts cut to customer drawings carry full lot traceability for regulated applications.

PSA (pressure-sensitive adhesive) backing, pad printing to MIL-STD-130, custom packaging, and validated clean-room production are all available on request.

See silicone product specs → Request a Quote

Related resources

• Gasket material selection guide. Full decision framework across every compound.
• Material comparison tool. Side-by-side silicone vs. other elastomers.
• Durometer / hardness chart
• Silicone rubber washers. Same compound, die-cut as washers.
• Silicone vs. fluorosilicone. When to upgrade.