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Silicone gaskets

Silicone gaskets for heat, cold and food contact.

Silicone stays soft and elastic from deep cold to oven heat, resists weather and ozone, and is clean enough for food contact. We cut silicone gaskets, washers and seals to your drawing in food-grade silicone rubber, and in sponge for low-load seals.

Request a quoteSilicone properties
Food-grade silicone rubber we cut
1 to 10 mm
Typical service range of silicone
-60°C to +200°C
High-precision digital flatbed cutting system

Why silicone

Why silicone keeps sealing when other rubbers harden.

Silicone rubber is built on a backbone of silicon and oxygen, the same bond found in glass and quartz, rather than the carbon chain of other rubbers. That backbone is far more stable in heat and far more flexible in cold. Where nitrile and neoprene harden and crack above about 100°C, silicone keeps its elasticity to about 200°C, and it stays soft at -60°C, when most rubbers are stiff.

It also shrugs off ozone, ultraviolet light and weathering, is odourless and tasteless, and is a good electrical insulator. Food-grade compounds make it the usual gasket rubber for ovens, food processing and drinks equipment.

Silicone's weaknesses are mechanical and chemical: it tears and abrades easily, swells in fuels and many oils, and degrades in high-pressure steam. Our guide to rubber gasket materials shows how it compares with the other elastomers.

All rubber gasket materials

Properties

Silicone rubber properties for gasket design.

These are typical values for solid silicone rubber sheet, for comparing materials at the design stage. The data sheet for the grade we supply applies to your part.

Notice the contrast: silicone's temperature range and electrical properties are the best of the common rubbers, but its tensile and tear strength are among the lowest. Design silicone gaskets to be clamped, not stretched, scraped or slid.

Silicone gaskets cut to your drawing

Solid silicone rubber: typical properties

General values, not a specification

General

Polymer
Silicone rubber (VMQ)
Density
1.1 to 1.5 g/cm³, by compound

Mechanical

Hardness
20 to 80 Shore A; 50 to 70 Shore A is common
Tensile strength
5 to 10 MPa
Elongation at break
200% to 600%
Tear and abrasion resistance
Low compared with other rubbers
Compression set
Low over a wide temperature range

Thermal

Service temperature
-60°C to +200°C
Short-term peak
About +250°C in heat-stabilised grades
Thermal conductivity
About 0.2 W/m·K

Electrical

Dielectric strength
About 18 to 25 kV/mm

Resistance

Ozone, UV and weather
Excellent
Attacked by
Fuels, many mineral oils, concentrated acids and alkalis, steam above about 120°C

Typical published values for solid silicone. Ask for the data sheet of the grade we supply.

What we cut

Solid, sponge and foam silicone gaskets.

Solid silicone rubber is for gaskets and washers that hold pressure or need a firm, durable seal. Silicone sponge is closed-cell: it compresses in volume and seals oven doors, lighting housings and enclosures at a light closing force. Silicone foam is softer still, for cushioning and gap filling. Our guide to foam and sponge gaskets compares silicone sponge with other foams.

Silicone gaskets are punched with a cutting tool for production runs, or cut without a tool for prototypes and thick sheet; see water jet and laser cutting. Sponge can be supplied with an adhesive backing, and as kiss-cut parts on a liner.

  • Cut to your drawing

    Gaskets, washers, seals, strips and complex profiles.

  • Grade advice

    Solid or sponge, food grade or general, matched to the service.

Contact our sales team

Silicone from PSG

Materials and thicknesses

Food grade silicone rubber
1.000 to 10.000 mm
General-purpose solid silicone
On request
Silicone sponge (closed cell)
On request
Silicone foam
On request
Adhesive backing
On request
Cutting
Punched with a cutting tool or water jet cut

Other grades, colours and thicknesses on request.

A set of cut gaskets for a car transmission

Food contact

Food-grade silicone gaskets.

Food-grade silicone is compounded from ingredients approved for contact with food, and is typically made to meet FDA 21 CFR 177.2600 in the United States and the framework regulation (EC) No 1935/2004 for food-contact materials. It is odourless, does not taint food or drink, and withstands repeated hot washing and cleaning.

For a food-contact part, the material grade is only half of the story: you also need the declaration of compliance that applies to it. Ask us for the declaration for the grade we supply, and tell us the food type, the temperature and the contact time so we can check it.

Food processors often specify a colour, such as white, red or a metal-detectable blue, so that a lost fragment can be found. Ask us about the colours available for your part.

Talk to our technical team

Applications

Where silicone gaskets are used.

Silicone is chosen when the temperature rules out other rubbers, when the seal touches food or skin, or when it must last outdoors.

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Limits

Limits of silicone: tear, abrasion, fuels and steam.

Silicone is a superb static seal, but there are four places it should not go.

  • Tearing and abrasion

    Silicone tears easily once nicked and wears quickly against moving parts. Use it for static seals, avoid sharp edges, and do not use it where the gasket slides or scrapes.

  • Fuels and oils

    Fuels and many mineral oils swell silicone. For oil and fuel, use nitrile, or a fluoroelastomer when it is also hot.

  • High-pressure steam

    Steam above about 120°C slowly breaks down the silicone backbone. For steam, peroxide-cured EPDM or PTFE is usually better.

  • Concentrated acids and alkalis

    Strong acids and alkalis attack silicone. Check any cleaning chemicals too, especially in food plants.

  • Gas permeability

    Silicone lets gases through more readily than other rubbers, so it is a poor choice for vacuum or gas-tight seals.

O-rings and mouldings

Silicone O-rings and moulded silicone parts.

Not every silicone seal can be cut from sheet. A round-section O-ring, a seal with a lip or a bead, or a three-dimensional part has to be moulded or extruded instead.

If your part needs silicone O-rings or a moulded silicone seal alongside the flat gaskets we cut, tell us what you need. We will tell you what we can supply and how, and quote the moulded and cut parts together so that one order covers the assembly.

For most flat seals, though, a cut gasket is quicker and cheaper than a moulding, because it needs at most a simple cutting tool rather than a mould.

A flat gasket cut from sheet is usually quicker and cheaper than a moulding.
Ask about silicone parts

Silicone gasket FAQs

Silicone gasket questions, answered.

Can't find what you need? Our technical team is happy to help.

Ask our team
Are silicone gaskets food safe?

Food-grade silicone is. It is made from ingredients approved for food contact, typically to FDA 21 CFR 177.2600 and Regulation (EC) No 1935/2004, and is odourless and taint-free. General-purpose silicone is not automatically food safe, so ask us for the declaration that applies to the grade before you order.

What temperature can silicone gaskets withstand?

Silicone is typically used from about -60°C to +200°C continuously, with heat-stabilised grades taking short peaks to about +250°C. It stays flexible at low temperatures, where most rubbers stiffen. The data sheet for the grade we supply gives its rated limits.

Solid or sponge silicone?

Choose solid silicone for gaskets and washers that are bolted up or must hold pressure. Choose closed-cell silicone sponge for doors, lids and enclosures that close with a light force, or where the gap is uneven: sponge compresses in volume and seals at a much lower load.

Is silicone oil resistant?

Not reliably. Silicone copes with some hot lubricating oils, but fuels and many mineral oils swell and weaken it. For oil and fuel, nitrile is the standard choice, and FKM fluoroelastomer is used when the oil is hot as well.

Do you supply silicone O-rings?

O-rings are moulded rather than cut from sheet. If you need silicone O-rings or moulded seals alongside cut gaskets, tell us the sizes and quantities, and we will confirm what we can supply and quote for them with the rest of your parts.

Can silicone gaskets be self-adhesive?

Yes. Silicone sponge and thin silicone sheet can be supplied with an adhesive backing. Silicone is hard to bond to, so it needs an adhesive made for silicone; tell us the surface and the temperature, and we will suggest a suitable one.

Have a silicone gasket to specify?

Send us the drawing, the temperatures, the medium and the quantity, and tell us if the part touches food. Our technical team will confirm the grade and quote for the cut parts.

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