Aerospace Sealing Solutions
International Seal supplies precision sealing solutions for aerospace applications where performance, reliability and material selection are critical. Our seals, O-rings and engineered components are designed to support demanding environments and exacting operational standards. From fuel and hydraulic systems through to ground support equipment and production tooling. Standard AS568 sizes, metric sizes and fully bespoke geometries are all supported, with full material traceability on request.
Seals, O-Rings & Gaskets for Aerospace Applications
Aerospace programmes need the same part, to the same specification, for years. Where a component is qualified into an assembly, changing compound or source is rarely a small decision, so continuity of supply matters as much as the initial specification. We can supply against a fixed compound reference and hold that specification across repeat orders, with material certification and batch traceability available on request. Tell us at enquiry stage whether the part is production, first-article or a one-off replacement, and whether documentation has to accompany each delivery.
Engineered for Demanding Flight & Manufacturing Systems
- High-performance O-rings for fuel, hydraulic and pneumatic systems
- Custom gaskets for controlled aerospace assemblies
- Specialist sealing materials for temperature, pressure and chemical resistance
- Precision components supporting traceability and consistent production quality
Fuel, Hydraulic and Pneumatic System Sealing
Most aerospace sealing enquiries come down to a fluid and a temperature range. Fuel contact pushes you towards FKM or fluorosilicone; phosphate ester hydraulic fluid rules out hydrocarbon elastomers altogether and needs EPDM; ducting and instrumentation at wide temperature swings usually points to silicone.
Altitude complicates it further. A compound that handles fuel at ambient temperature may lose flexibility at the low end of the operating range, which is why fluorosilicone (FVMQ) is specified where both fuel resistance and low-temperature flexibility are needed in the same seal. If your specification gives you a fluid and two temperature extremes, send all three and we will tell you which compounds satisfy all of them rather than just the obvious one.
Materials for Aerospace Environments
Material choice in aerospace is rarely a single-variable decision. Fluid compatibility, temperature range, compression set and long-term ageing all have to be balanced against the operating conditions of the specific system.
- FKM (Fluoroelastomer) for fuel and lubricant contact with high temperature resistance to around 200°C
- FVMQ (Fluorosilicone) for fuel resistance combined with low temperature flexibility at altitude
- Silicone (VMQ) for wide temperature range static sealing, ducting and instrumentation
- EPDM for phosphate ester hydraulic fluids where hydrocarbon elastomers fail
- PTFE and filled PTFE for chemical inertness, back up rings and low friction dynamic applications
- FFKM (Perfluoroelastomer) for the most aggressive chemical and high temperature combinations to 320°C
If you are unsure which compound suits your operating conditions, send us the fluid, temperature range and pressure and we will make a recommendation.
Industry Standards & Compliance
Components are supplied against the material and dimensional standards aerospace buyers specify, including AS568 sizing, AMS material specifications, MIL specifications and SAE ARP practices.
Where a programme requires it, we source from manufacturing partners holding AS9100D and NADCAP accreditation, and can provide their certification alongside the parts. Confirm the requirement at enquiry stage.
Related Products
O-rings in FKM, FVMQ, silicone and EPDM, custom gaskets, metal seals for high-temperature and high-pressure joints, PTFE components and back-up rings, engineered seal kits and custom moulded parts. See our compound reference for available grades.
Aerospace Sealing FAQs
Which O-ring material is used for aerospace fuel systems?
FKM is the usual starting point for fuel and lubricant contact with elevated temperature. Where the seal also has to stay flexible at low temperature — typical at altitude — fluorosilicone (FVMQ) is specified instead, because it combines fuel resistance with better low-temperature performance. The correct choice depends on the fuel, the full temperature range and the pressure.
What seal material is compatible with phosphate ester hydraulic fluid?
EPDM. Phosphate ester fluids attack hydrocarbon-based elastomers such as NBR, so a seal that performs well in mineral-oil hydraulics will fail in a phosphate ester system. This is one of the most common material mismatches in aerospace hydraulics, so confirm the fluid type before specifying.
Do you supply O-rings to AS568 sizes?
Yes. We supply AS568 dash sizes, metric sizes and non-standard dimensions to your inside diameter and cross-section. Tell us the dash number if you have it, or the measured dimensions if you are working from an existing seal.
Can you provide material certification and traceability?
Material certification and batch traceability are available on request. Tell us at enquiry stage whether documentation has to accompany each delivery, and whether the part is production, first-article or a one-off replacement, so the right paperwork is prepared from the outset.
Can you hold a compound specification across repeat orders?
Yes. Where a component is qualified into an assembly, we can supply against a fixed compound reference and hold that specification across repeat orders, so the part you re-order is the part you qualified.
What do you need to quote an aerospace seal?
The dimensions or a drawing, the fluid in contact, the operating temperature range, the pressure, and any material specification or documentation requirement. If the compound is unspecified, send the operating conditions and we will recommend one.