Sealing questions, answered

It comes down to motion. Use a gasket for static, bolted flange joints; gland packing or a mechanical seal for rotating or reciprocating shafts. Gland packing is robust, repairable and tolerant of misalignment but allows a small controlled leak; a mechanical seal costs more up front but runs leak-free and is the right choice for hazardous, volatile or emission-controlled fluids.

A spiral-wound gasket interleaves a metal winding (typically 316L) with a soft filler such as graphite or PTFE, giving excellent recovery, a very wide temperature and pressure envelope, and resilience under thermal cycling — ideal for critical high-class flange joints. A compressed-fibre (CNAF) gasket is a soft, cut sheet suited to general-purpose, lower-class duty where cost and easy fabrication matter more than extreme conditions.

Flexible graphite is the workhorse for superheated steam, in both gasket and packing form, with a practical envelope to around +550°C. For critical steam flanges, a graphite-filled spiral-wound gasket adds the recovery needed to survive thermal cycling. Protect graphite from strong oxidising media, and confirm the specific pressure class on the datasheet.

PTFE has near-universal chemical resistance across the full pH range, which makes it the default for aggressive and mixed chemical service. Its limitations are mechanical, not chemical: it cold-flows (creeps) under sustained load and has a ceiling around +260°C. For demanding joints use a filled or expanded PTFE construction, or a PTFE-envelope gasket, to control creep.

Across the range, from cryogenic LNG service near -196°C up to roughly +650°C for metallic gaskets, and from vacuum up to 420 bar / Class 2500 on the highest-rated flange joints. No single material spans all of that — and a material rarely delivers its maximum temperature and maximum pressure at the same time. Tell us your worst-case condition and we'll specify to it.

Use the gasket's seating-stress-based torque from the datasheet, applied with a calibrated wrench and known thread lubrication, in a cross pattern over at least three passes. Generic 'as tight as it'll go' bolt-up is the most common cause of flange leaks — both over- and under-torquing damage the joint. Re-torque soft and spiral-wound gaskets after they settle and, for hot service, after the first thermal cycle.

Yes. Alongside standard catalogue items we die-cut and machine bespoke gaskets, sheets and seals to drawing or sample, including odd-form covers, large-diameter and one-off heat-exchanger gaskets. Send a drawing, the flange details or a physical sample together with the service conditions and we'll quote the right material and construction.

We supply water-approved and FDA 21 CFR-compliant grades — typically EPDM and silicone elastomers and specific PTFE compounds — for potable water, food, beverage and pharmaceutical contact. Compliance depends on the exact compound, so request the food- or water-grade variant and we'll provide the supporting documentation with the order.

As standard, orders carry material identification and traceability. On request we provide material certificates (including EN 10204 3.1 where applicable), compliance statements for PED/CE, FDA, ATEX and fire-safe duties, and recommended installation data such as bolt torque sequences. Specify the documentation you need on the enquiry so it's prepared with the parts.

Standard catalogue items and common cut gaskets generally ship from stock within a few working days. Engineered items — spiral-wound and metallic gaskets, cartridge mechanical seals and bespoke die-cut parts — are made to order, with lead time depending on material and quantity. For turnaround and breakdown support we can expedite; flag the required date on your enquiry and we'll confirm against it.