Silicone O-Rings
VMQ / Silicone Rubber Seals
Wayne Rubber manufactures custom silicone o-rings in FDA-compliant, USP Class VI, and industrial grades for high-temperature, food processing, medical, and outdoor applications. Available in all AS568, ISO 3601, and metric standard sizes as well as fully custom dimensions — molded in-house with custom silicone formulations across the full durometer range.
Why Silicone for O-Rings?
Silicone (VMQ) o-rings are specified when an application requires temperature performance that no standard elastomer can match, or when FDA compliance, biocompatibility, or purity is a non-negotiable requirement. Silicone’s service range of −75°F to +450°F (−59°C to +232°C) is the widest of any common o-ring material which makes it the only viable choice for high-temperature static sealing in ovens, exhaust-adjacent equipment, steam-aged environments, and cryogenic systems where NBR or EPDM would either harden or degrade.
Silicone is odorless, tasteless, non-leaching, and resistant to bacterial and fungal growth which makes it the dominant o-ring material for food processing equipment, medical devices, pharmaceutical production, and any application where contact with consumables requires FDA or USP validation.
Silicone o-rings are primarily suited to static sealing applications. Their tensile strength and tear resistance are significantly lower than nitrile or EPDM — in continuous dynamic (reciprocating) applications, silicone will wear faster than most alternatives. For high-cycle dynamic sealing involving elevated temperature, FKM fluoroelastomer is usually the more appropriate specification.
Silicone also has poor resistance to petroleum-based oils and fuels, concentrated acids, and steam. For any of those environments, nitrile, FKM, or EPDM respectively are the correct materials. Use the Chemical Resistance Guide to confirm silicone is compatible with your specific media.
Silicone O-Ring Material Specifications
Standard VMQ silicone compound properties for o-ring applications. Wayne Rubber formulates specialty grades for platinum-cured medical requirements, extended temperature service, metal-detectable food-line grades, and custom durometers.
| Property | Standard Value / Range |
|---|---|
| Temperature Range | −75°F to +450°F (−59°C to +232°C) Specialty grades: −103°F (−75°C) low-temp; intermittent to +500°F (+260°C) high-temp |
| Hardness (Durometer) | 20 to 80 Shore A Standard o-ring grades: 40, 50, 60, 70 Shore A |
| Tensile Strength | 600 – 1,500 psi (lower than NBR/EPDM — avoid dynamic applications) |
| Elongation at Break | 150% – 700% (grade-dependent) |
| Compression Set | Good (peroxide-cured); Excellent (platinum-cured grades) |
| Shrinkage Rate | 3–4% during molding (higher than NBR/EPDM — material-specific tooling required) |
| Standard Colors | Red/orange, white, translucent, gray, black; custom colors to RAL/Pantone available |
| ASTM Designation | ASTM D-2000 Class M2GE / FC (grade-dependent) |
| FDA Compliance | Available — FDA 21 CFR 177.2600 for food contact applications |
| USP Class VI | Available — platinum-cured medical-grade silicone upon request |
| 3-A Sanitary / NSF-51 | Available upon request for dairy and sanitary processing applications |
| Ozone / UV / Weather | Excellent |
| Oil / Fuel Resistance | Poor — not recommended for petroleum-based fluid contact |
| Steam Resistance | Fair — limited service; consider FKM or EPDM for steam-primary environments |
Silicone O-Ring Grades & Formulations
Silicone o-rings span a wider range of specialty grades than most elastomers. Wayne Rubber supplies the right grade for your compliance requirement, temperature range, and service environment.
General-purpose VMQ silicone for high-temperature static sealing in ovens, HVAC, industrial equipment, and outdoor environments. Most cost-effective silicone o-ring grade where FDA compliance is not required. Standard colors: red/orange, black.
Peroxide-free silicone compound compliant with FDA 21 CFR 177.2600 for food contact. Odorless, tasteless, and non-leaching. Used in food processing pumps, valves, blending equipment, and conveyor systems where o-ring contact with food product is possible. Standard colors: white, red/orange, translucent.
Platinum-cured silicone meeting USP Class VI biocompatibility requirements. Platinum curing delivers significantly better purity, lower extractables, and superior compression set vs. peroxide-cured grades. Required for medical devices, diagnostic equipment, and pharmaceutical processing where validated biocompatibility is mandatory.
Silicone compounds certified for dairy processing, beverage production, and other sanitary applications governed by 3-A Sanitary Standards or NSF Standard 51. Required for equipment sold into dairy, brewing, and food-grade fluid handling markets.
Silicone compound containing metal-detectable additives — typically blue in color — for food manufacturing lines where o-ring fragment contamination must be detectable by metal detection or X-ray inspection systems. Required by many food safety programs and GFSI standards for seals in direct food contact zones.
Specialty VMQ grades for service outside the standard silicone range: low-temperature grades maintain flexibility to −103°F (−75°C) for cryogenic and cold-chain applications; high-temperature grades handle intermittent exposure to +500°F (+260°C) for furnace, kiln, and exhaust-adjacent sealing.
Size Search & Gland Design
Use Wayne Rubber’s free technical tools to identify your silicone o-ring size and verify gland dimensions before requesting a quote. Note that silicone shrinks at 3–4% during molding — tooling for NBR or EPDM o-rings cannot be reused for silicone. Wayne Rubber accounts for material-specific shrinkage in all silicone tooling.
Look up standard silicone o-ring sizes across AS568, ISO 3601, Metric, and JIS B2401 by dash number, ID, or cross section. Full tolerances in inches and millimeters. 1,400+ sizes in the database.
Calculate gland depth, groove width, squeeze, and fill percentage for your silicone o-ring. Design gland fill toward the lower end of the 65–85% target range for silicone to accommodate its higher thermal expansion coefficient.
Static Sealing: Where Silicone O-Rings Excel
Static Applications
Silicone o-rings perform best in static sealing applications where there is no relative motion between the o-ring and the mating surfaces after assembly. Face seals, flange seals, cover plate seals, port seals, and any application where the o-ring is compressed and held in place are ideal for silicone. Typical squeeze of 15–25% of cross-section diameter is recommended for static silicone o-rings.
Silicone’s excellent compression set resistance — particularly in platinum-cured medical grades — allows it to maintain sealing force over extended service intervals at high temperatures where most elastomers would take a permanent set and lose sealing contact. This makes silicone the standard o-ring material for high-temperature static seals in industrial ovens, lighting assemblies, and exhaust-adjacent components.
Dynamic Limitations
Silicone o-rings should not be specified for continuous reciprocating dynamic sealing. Silicone’s tensile strength (600–1,500 psi) and tear resistance are significantly lower than nitrile (1,000–3,000 psi) or EPDM, and silicone will wear rapidly under friction from sliding surfaces.
If your application involves reciprocating motion and also requires high-temperature or food-contact compliance, the following alternatives should be evaluated: FKM fluoroelastomer for high-temperature dynamic sealing, or HNBR for elevated-temperature oil service with better abrasion resistance than standard silicone. Wayne Rubber’s engineering team can evaluate your specific motion profile and recommend the best compound and gland geometry.
Silicone O-Ring Applications by Industry
Silicone o-rings appear across a uniquely wide range of industries — from food production lines to aerospace altitude sealing — because no other common elastomer combines wide temperature range with FDA compliance and long-term outdoor stability.
Silicone vs. Other O-Ring Materials
Silicone is the right choice when temperature range and compliance requirements rule out every other option. This table helps confirm silicone is the correct specification — or identifies when a more cost-effective or better-performing alternative would serve the application.
| Property | Silicone (VMQ) | NBR (Nitrile) | EPDM | FKM | HNBR |
|---|---|---|---|---|---|
| Max. Service Temp. | +450°F (+232°C) | +250°F (+121°C) | +300°F (+149°C) | +400°F (+204°C) | +300°F (+149°C) |
| Min. Service Temp. | −75°F (−59°C) | −40°F (−40°C) | −65°F (−54°C) | −15°F (−26°C) | −40°F (−40°C) |
| FDA Compliance | ✓ Excellent availability | ✓ Available | ✓ Available | ✓ Available | ▶ Limited |
| USP Class VI | ✓ Excellent (platinum-cured) | ✗ Not standard | ✗ Not standard | ▶ Limited grades | ✗ Not standard |
| Dynamic Sealing | ✗ Poor (static only) | ✓ Excellent | ▶ Limited motion | ✓ Good | ✓ Excellent |
| Petroleum Oil Resistance | ✗ Poor | ✓ Excellent | ✗ Poor | ✓ Excellent | ✓ Excellent |
| Ozone & UV | ✓ Excellent | ✗ Poor | ✓ Excellent | ✓ Excellent | ✓ Good |
| Relative Cost | Medium – High | Low | Low – Medium | High | Medium – High |
Silicone O-Ring Manufacturing at Wayne Rubber
Custom Silicone Compounding
Wayne Rubber custom formulates various silicone grades including commercial, FDA, USP Class VI, 3-A Sanitary, metal-detectable, and specialty temperature grades. Virgin silicone polymer only — no regrind in any food or medical grade compound. Full material certifications and compliance documentation provided with every FDA and medical-grade order. See the silicone rubber material page for full compound data.
Material-Specific Tooling
Silicone rubber shrinks at 3–4% during curing — significantly more than NBR (1.5–2%) or EPDM. Tooling designed for other elastomers cannot be used for silicone without producing undersized parts. Wayne Rubber maintains silicone-specific tooling that accounts for VMQ shrinkage rates, ensuring dimensional conformance to AS568, ISO 3601, and custom drawing tolerances in the finished o-ring.
Standard & Custom Sizes
We manufacture silicone o-rings in all AS568, ISO 3601, Metric, and JIS B2401 standard sizes, as well as fully custom ID × CS combinations for non-standard glands or specialty equipment. Use the O-Ring Size Search to confirm your standard size, or contact us with your exact dimensions and compliance requirement for a custom quote.
Quality & Compliance Documentation
Every silicone o-ring batch is dimensionally inspected and material-tested before shipment. For FDA, USP Class VI, and 3-A Sanitary grades, we provide full material certifications, certificates of conformance, and compliance documentation. ASTM D2000, AS568, and ISO 3601 standards are supported. Medical and food-grade orders are handled with appropriate production controls to maintain material traceability. Our full testing and quality capabilities are available for review.
Request a Quote for Custom Silicone O-Rings
Provide your o-ring size (dash number, ID × CS, or drawing), required grade (industrial, FDA, USP VI, etc.), and application details. Wayne Rubber will respond with material recommendations and pricing.