Cryogenic Equipment Gaskets.

Why most gaskets shatter below −40°F

Most gasket materials were engineered for the temperature range between roughly −40°F and +300°F because that is where most industrial sealing happens. Drop below −40°F and nearly every rubber compound turns brittle, loses elasticity, and cracks under the first thermal cycle. The compounds that survive cryogenic service are the ones whose polymer chains stay mobile at extreme cold: silicone, fluorosilicone, and fluoropolymers like PTFE. Pick the wrong one and you get a gasket that seals during room-temperature assembly and then fractures the instant the line is chilled down.

Cannon Gasket produces cryogenic gaskets and seals for LNG storage and transfer systems, industrial gas (O₂, N₂, Ar) processing, medical imaging (superconducting MRI magnet cryostats), semiconductor fab cryo lines, and aerospace fuel-system applications. We work in silicone, fluorosilicone, PTFE sheet and tubing, and Kapton^®film.

Compounds that stay flexible at cryo temperatures

Material selection below −40°F is a short list: anything that isn't silicone, fluorosilicone, PTFE, or polyimide should be treated as unverified until you have manufacturer data confirming cryo performance.

• Silicone (VMQ) remains flexible down to approximately −50°F in standard grades, deeper in specialty grades. The default elastomer for most cryogenic sealing because it also carries FDA and USP Class VI variants for medical / pharmaceutical cryo and handles the positive side of the temperature range up through +500°F.
• Fluorosilicone (FVMQ) covers silicone's temperature range plus resistance to fuels, solvents, and aromatic hydrocarbons that attack plain silicone. The standard spec for aerospace cryogenic fuel systems, ground-support equipment, and propellant handling.
• PTFE / Teflon^® is stable from −328°F to +500°F. PTFE gaskets are standard on liquid oxygen (LOX), liquid nitrogen (LN₂), and LNG service where chemical inertness and cleanliness matter more than elastomeric compliance. PTFE is rigid, so if the flange needs compression-style sealing, pair PTFE with a silicone gasket or use expanded PTFE (ePTFE) sheet.
• Kapton^® (polyimide film) remains stable to −452°F. The standard for electrical isolation in cryogenic instruments (MRI gradient coils, superconducting magnet assemblies, semiconductor cryo chucks) where both the cold-end and dielectric-strength requirements matter.
• G-10 fiberglass is a rigid glass-epoxy laminate used as a cryogenic structural washer / isolator where high compressive strength plus dielectric isolation is needed (superconducting magnet supports, dewars). Stable to roughly −65°F in commercial grades; aerospace-qualified G-10CR extends this further.

How cryogenic gaskets fail on chill-down

• Brittle fracture on chill-down. The classic cryo failure. A material that behaved elastomerically at room temperature turns glassy below its brittle-point and cracks under the thermal-contraction load. Fix: verify the material T_g(glass-transition temperature) and brittle point are at least 20°F below the minimum service temperature, and prefer silicone / fluorosilicone over nitrile or neoprene.
• Loss of elastic recovery on warm-up.Some elastomers survive the cryo soak but don't rebound when warmed; the gasket takes permanent set, loses compression, and leaks on the next cycle. Fix: specify a low compression-set grade of silicone (typically a platinum-cured VMQ) and confirm with supplier datasheet.
• Gas permeation and diffusion. Over long hold-times, even a well-selected elastomer gasket will slowly diffuse light gases (He, H₂, N₂). If leak rate matters (e.g. vacuum-insulated dewars, helium service), move to PTFE or metallic sealing.
• Oxygen incompatibility. Liquid oxygen (LOX) service requires oxygen-compatible materials, as many otherwise-fine elastomers ignite under LOX. Specify LOX-batch-cleaned PTFE, ASTM G63 / G72 verified materials.
• Thermal-cycling fatigue of bonded assemblies. PSA-backed gaskets in cryo service can delaminate as differential thermal contraction stresses the adhesive line. Specify cryo-rated PSA (typically silicone-based) or mechanically retained gaskets for repeated-cycle applications.

Cryogenic seal profiles we cut

Cryogenic gasket work spans small-diameter fitting and valve seals (often O-ring cross-sections, specified as lathe-cut or molded), larger-diameter flange gaskets for process piping, thin-film dielectric washers for cryo instrumentation, and custom-profile cryostat seals. Cannon Gasket die-cuts and waterjet-cuts these from sheet stock, and can supply complementary lathe-cut and molded components through our O-ring and lathe cut programs.

Cryogenic compliance callouts by end-use

Cryogenic gasket work intersects several regulatory regimes depending on end-use: ASME B31.3 (process piping) and B31.12 (hydrogen service) for industrial gas; ASTM G63 / G72 for oxygen compatibility; FDA 21 CFR 177.2600 and USP Class VI for medical imaging gaskets that contact patient-facing surfaces; AMS-S-8660 and NASA PED (propellant) specs for aerospace cryogenic fuel systems; SEMI F70 and related for semiconductor cryo. Cannon Gasket's ISO 9001 quality system supports documentation and lot traceability for these applications.

For a broader material decision framework, see our gasket material selection guide.

Materials Cannon Gasket supplies for cryogenic equipment

Cryo sealing across aerospace, medical, and semiconductor

Cryogenic gasket work sits inside our aerospace, medical, and electronics / semiconductor programs, same materials, same documentation standards, just specified against a cold-end temperature instead of a hot- end one.

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