- Family
- VMQ (silicone)
- Standard range
- -54 C to 204 C (Parker® O-Ring Handbook ORD 5700)
- Special grades
- to -115 C, to 260 C
- Durometers
- AMS 3301 to 3305 silicone compounds in Parker's handbook, nominal 40 to 80 Shore A; each compound holds its own band, and the five bands together span 35 to 85 A (S0469-40 to S0614-80, Table 8-4)
- Standards
- ASTM D1418 VMQ; AMS 3301 to 3305; AMS7267; A-A-59588; FDA 21 CFR 177.2600, USP Class VI on specific compounds
- Product
- O-rings in AS568 and ISO 3601 sizes, quoted in the compound the print names
Service temperatures here are the family figures published in Parker O-Ring Handbook ORD 5700A/US §2.2; the compound datasheet and your application govern the final choice.
Larger and non-standard sizes: an O-ring beyond the molded size lists can be supplied as a spliced and vulcanized O-ring, which the maker joins from cord of the same compound. That page lists, family by family, which makers offer the compound as cord, and what to send for a quote.
Silicone O-rings cover a wide temperature range and are widely used in food, beverage and medical equipment in static service. The Parker O-Ring Handbook (ORD 5700) rates the family from -54 C (-65 F) to 204 C (400 F), with special compounds reaching -115 C and 260 C. Conquest supplies silicone O-rings in every AS568 and metric size, including compounds offered by their makers as FDA compliant and USP Class VI, and the AMS 3301 to 3305 aerospace grades by hardness.
Silicone O-ring specifications
| Property | Value | Source |
|---|---|---|
| Continuous service temperature | -54 C to 204 C (-65 F to 400 F); special compounds -115 C and 260 C | Parker ORD 5700 |
| Cure | Peroxide or platinum; platinum-cured grades for medical and life-science listings | Wacker Chemie, Solid Silicone Rubber (HTV) product-group page; Rogers Corporation, BISCO® MS-1600 data sheet 180-358 |
| Material designation | VMQ (general), PVMQ (low temperature) under ASTM D1418 | ASTM naming |
| Aerospace specifications | AMS 3301, 3302, 3303, 3304 (AS3582), 3305 by hardness; AMS7267 (AS9385, AS9386); A-A-59588 | SAE Mobilus records, read 2026-09-24 and 2026-09-27 |
| Compliance available | FDA 21 CFR 177.2600 and USP Class VI on specific compounds | Rogers Corporation, BISCO MS-1600 Series Medical and Life Science Solid Silicone data sheet 180-358, page 1 |
| Service | Static seals only | Parker ORD 5700 |
| Strong against | Dry heat, extreme cold, ozone and weathering, dielectric service, food contact | Parker ORD 5700 section 2.2 |
| Weak against | Dynamic service (tear and abrasion), fuels and petroleum oils, steam, concentrated acids | Parker ORD 5700 section 2.2 |
| Gland note | Reduce the design-chart extrusion clearances by 50 percent for silicone | Parker O-Ring Handbook ORD 5700, section 4.2 |
Sizes and forms we supply
Every AS568 size, the general-purpose dash sizes and the boss-seal sizes alike, and the ISO 3601 metric series, in the durometers listed above; O-ring cord for rings spliced and vulcanized by the maker in odd diameters (static service only); and X-rings and backup rings in the same families. The AS568 chart and the metric chart carry the dimensions, and the dash number guide explains the numbering.
Where silicone O-rings work, and where they fail
| Medium or condition | Verdict | Note (Parker O-Ring Handbook ORD 5700) | Handbook alternative |
|---|---|---|---|
| Dry heat: ovens, heaters, lighting | Excellent | The core application | FKM where oil is present |
| Extreme cold | Excellent | Flexible where other elastomers stiffen | Low-temperature FKM, only to -46 C |
| Food, beverage, pharmaceutical contact (static) | Excellent on compliant compounds | The food and medical default | EPDM for steam and clean-in-place |
| Ozone, weather, dielectric duty | Excellent | Saturated backbone | EPDM at lower cost for ozone and weather |
| Hot water | Good | Steam degrades standard compounds; the compound sheet states any steam rating | EPDM for steam |
| Fuels, petroleum oils | Not recommended | Fluorosilicone or Viton® | Fluorosilicone for fuel at silicone temperatures |
| Dynamic seals, vacuum | Not recommended | Low tear strength; gas-permeable | Nitrile, FKM or polyurethane for motion; butyl or FKM for vacuum |
Which specifications call out silicone O-rings?
Aerospace silicone is called out by SAE AMS documents graded by hardness; medical and food silicone by compliance listings. Revisions are read from the SAE Mobilus records (read 2026-09-24 and 2026-09-27), the M25988 status from DLA ASSIST (read 2026-09-24 and 2026-09-28), and hardness bands from the Parker handbook's section 8 tables (read 2026-09-24).
| Callout | What it is | Part numbers or note |
|---|---|---|
| SAE AMS 3301, 3302, 3303, 3304, 3305 | General-purpose silicone by hardness | AMS3304 (65 to 75 Shore A) is at revision J (2019); AS3582 is its O-ring part standard |
| SAE AMS7267 | Heat-resistant, low compression set silicone sealing rings, 70 to 80 Shore A in the Parker handbook's section 8 table | SAE AS9386 (revision B, 2021), titled O-ring molded from AMS7267 silicone (VMQ) rubber; SAE AS9385 (revision A) was cancelled in October 2020 |
| A-A-59588 | Commercial item description commonly cited as the successor to ZZ-R-765 silicone (succession is industry usage; check the print) | Grades by hardness; the print names the grade |
| FDA 21 CFR 177.2600 | Food-contact compliance, self-certified by the compound maker | White or translucent food-grade compounds; see the FDA guide |
| USP Class VI | Biological reactivity report for medical and pharmaceutical service | Typically platinum-cured compounds; see the USP Class VI guide |
| Fluorosilicone: MIL-DTL-25988, SAE AMS-R-25988 | Fuel-resistant silicone for aerospace fuel systems | M25988 fluorosilicone rings are ordered to the MIL-DTL-25988 slash sheets (/1 to /4, Active); DoD's 2025 notice marks the base document inactive for new design and in part superseded by SAE AMS-R-25988. |
The mil-spec chart lists the full set.
Typical applications
Oven, heater and lighting seals in dry heat; food and beverage dispensing and processing equipment on FDA-compliant compounds; medical devices and pharmaceutical fittings on platinum-cured, USP Class VI compounds; electrical enclosures and connectors where dielectric strength matters; cold-room, freezer and outdoor equipment at the cold end of the Parker range above, and colder on special compounds; and aerospace static seals to the AMS 3301 to 3305 hardness series.
Where silicone fits
Temperature extremes, clean and compliant static service, and cold-weather equipment. For fuel at silicone temperatures, the usual fit is fluorosilicone; for oil or motion, Viton or nitrile. The FDA guide covers the compliance schemes.
Sources: 21 CFR 177.2600; A-A-59588; AMS 3301; AMS7267; AS3582; AS568; ASTM D1418; ASTM D2000; ISO 3601; ORD 5700; Parker O-Ring Handbook; USP Class VI; Parker O-Ring Handbook ORD 5700, section 2.2 (read 2026-09-14), sections 4.2 and 8 (read 2026-09-24) and page 2-10 (read 2026-09-25); SAE Mobilus records for AMS3304, AS3582, AMS7267, AS9385, AS9386 and AMS-R-25988, read 2026-09-24; DLA ASSIST records for MIL-DTL-25988/1 to /4 (idents 18214 to 18217, Active, validation notices 2026-04-21) and MIL-DTL-25988D (ident 18213), read 2026-09-24; the MIL-DTL-25988D Notice 1 text (2025-06-11), read 2026-09-28; SAE Mobilus current-revision records (AS9385A, AS9386B), read 2026-09-27.
Parker is a trademark of Parker Hannifin Corporation. Viton is a trademark of The Chemours Company; BISCO is a trademark of Rogers Corporation. No affiliation with or endorsement by either trademark owner is implied.
Frequently asked
Is a white silicone O-ring food grade?
Only if its compound is listed; color is pigment. The compound sheet is the evidence.
Can silicone O-rings be autoclaved?
Specific medical compounds are rated for steam sterilization cycles; standard silicone degrades in steam, and the compound sheet states any steam rating.
Why is silicone static-only?
Low tear and abrasion strength; a rod or piston seal in silicone wears quickly.
Is a red silicone O-ring different from a white one?
Only in pigment. Red or orange is the traditional iron-oxide color; white and translucent are common in food and medical compounds. Compliance comes from the compound sheet, not the color.
What is fluorosilicone?
FVMQ: silicone with fluorine on the side chains, giving fuel and oil resistance at silicone-like temperatures (-73 C to 177 C per the Parker table). It is the aerospace fuel-system material behind AMS-R-25988, and it is static-only like silicone.
Which durometer?
70 to 80 A suits most applications (Parker handbook, page 2-10); the AMS 3301 to 3305 series covers nominal 40 to 80 A for aerospace, each compound held to its own band, and the five bands together span 35 to 85 A. The durometer guide explains the trade-off.
Does silicone take a set?
Silicone's compression set resistance at temperature is good, one reason it is chosen for hot static seals. The compression set guide covers what over-squeeze and heat do to any material.
Does silicone need a different extrusion clearance?
Yes, a smaller one. The Parker handbook (section 4.2) reduces the tabulated clearances by 50 percent for silicone. Where the print or the ring maker names a clearance, that figure governs.
What does AS9385 or AS9386 on a drawing mean?
Both are SAE part standards for AMS7267 silicone O-rings. SAE AS9386 is current at revision B (2021); SAE AS9385 was cancelled in October 2020, with no replacement named on its record. Send the callout and dash number as printed. AMS7267 material is 70 to 80 Shore A in the Parker handbook's AMS table.
Orders are handled under Conquest Seal's AS9100D quality management system, whose certificate scope includes distribution.
Send the part number and the quantity for Silicone
The AS568 dash number or the inside diameter and cross-section, the durometer, the quantity, the medium and temperature, and any specification the print names. A Conquest representative replies. Quotes answered within one business day. A person answers (714) 632-9830, Pacific business hours.
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