Custom Silicone Seals, Gaskets & O-Rings
Silicone seals, gaskets and O-rings rated from −40 °C to 230 °C, made by compression moulding, extrusion or die-cutting depending on the shape. Send seven data points and we can quote without a week of questions.
- −40 to 230 °C
- Moulded / extruded / die-cut
- MOQ from 500
- In-house tooling
| Material | HCR silicone; fluorosilicone on request for oil resistance |
|---|---|
| Temperature | −40 to 230 °C continuous |
| Hardness | Shore A 30–80 (ASTM D2240) |
| Process | Compression moulded · extruded profile · die-cut sheet |
| Cross-section | O-ring cord 1–20 mm · custom profile on drawing |
| Tolerance | ±0.1 mm moulded · ±0.3 mm extruded |
| MOQ | 500 pcs (stock O-ring) / 1,000 (die-cut) / 3,000 (new mould) |
| Tooling | Die $150–600 · extruded die $300–1,500 · compression mould $1,500–8,000 |
| Sampling | 3–7 days for existing tooling · 10–15 days for a new mould |
| Lead time | 15–25 days after sample approval |
| Testing | Hardness per ASTM D2240 · RoHS / REACH arranged per order |
Values marked on request depend on your drawing. Send it and we will confirm in writing.
Can we make yours?
- O-rings, flat gaskets, washers, custom profiles
- −40 to 230 °C continuous service
- Shore A 30–80, moulded, extruded or die-cut
- Compression set and hardness reports on request
- 500–100,000 pcs per order
Where we stop
- Hard plastic injection moulding (ABS / PC structural parts)
- Metal machining, stamping or plating
- Factory-level certificates — we arrange third-party testing per order instead
Process and material
Pick the process by shape, not by habit
A round O-ring with existing tooling costs nothing to tool and runs from 500 pcs. A flat gasket is usually die-cut from sheet. A custom profile is extruded, or moulded if it has features along its length. Choosing wrong is the main reason quotes differ by 4× for the same drawing.
What we need to quote
Seven things: seal family (O-ring / moulded / extruded / die-cut), critical dimensions and cross-section, target Shore A and tolerance, service temperature and contact medium, silicone grade, annual volume, and colour. With those we can quote without coming back with questions.
Compression set matters more than hardness
A seal that leaks after six months usually failed on compression set, not on hardness. If the joint stays compressed at temperature, tell us — we will recommend a grade and post-cure that holds its shape rather than just matching a durometer number.
Questions buyers ask about silicone seals & gaskets
What is your MOQ for a custom gasket?
500 pcs for stock O-ring sizes, 1,000 for die-cut flat gaskets, and 3,000 for a new compression mould. The MOQ follows the tooling cost, not our preference.
What information do you need to quote a seal?
Seven things: seal type, dimensions, hardness and tolerance, temperature and medium, silicone grade, annual volume, and colour. Send those and the quote comes back without a round of questions.
Can you do fluorosilicone for oil contact?
Yes, for applications where standard silicone swells in oil or fuel. It costs more and has a narrower temperature window, so we only recommend it when the medium requires it.
What temperature range is realistic?
−40 to 230 °C continuous for standard grades. Short excursions to 250 °C are survivable but shorten life. Below −40 °C the material stiffens and sealing force drops.
Do you provide hardness certificates?
We measure hardness in-house per ASTM D2240 on every batch, and can arrange third-party verification for your order if you need a lab report rather than our own reading.
The spec table above, the tolerance notes, and the list of what we need from you — as a two-page PDF you can forward to your team.
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Send your spec, get a quote
Tell us what you need and how many. within 1 business day (GMT+8) — usually much sooner. If you already have a drawing or 3D file, attach it and skip the back-and-forth.
- Email [email protected]
- Phone +86-755-21011840
- WhatsApp +852 5161 2090