Our team here at PTM still cuts a steady volume of cork gaskets every month, which might surprise anyone assuming synthetic rubber sheet has replaced cork everywhere. It hasn’t. Cork remains one of the most specified sealing materials in automotive and industrial workshops, and the reasons for that come down to how the material actually behaves under load rather than tradition alone.
Cork compresses in one direction without losing its shape in the other, which lets it conform to uneven or slightly damaged flange faces that would defeat a stiffer synthetic sheet. That property alone explains why cork gaskets keep turning up on engine sumps and valve covers decades after supposedly better alternatives arrived, and it’s just as common on transformer housings. Natural cork on its own suits light duty sealing, but most of what leaves our workshop is bonded with nitrile or neoprene rubber, which adds oil and fuel resistance without giving up the compressibility cork is known for. You can see the different grades we stock on our cork gaskets page.
Nitrile-bonded cork holds up particularly well against oils and fuels, and it copes just as well with hydraulic fluid, which is why it’s the grade most automotive and heavy machinery customers ask for by name. Neoprene-bonded cork trades a little of that oil resistance for better heat tolerance, so it tends to appear more in refrigeration and compressor applications instead. Cork also does a quietly useful job of damping vibration and sound, worth remembering if noise reduction matters as much as sealing in your application.
Cost plays a part too. Cork remains cheaper to produce than most synthetic rubber sheet of comparable thickness, and for equipment where the operating conditions sit within cork’s comfort zone, there’s rarely a reason to pay more for a material that won’t outperform it. If your application does push into higher pressures or aggressive chemical exposure, our rubber gaskets range covers the materials better suited to that end of the spectrum.
Cork isn’t the right choice for every seal, but for the applications it suits, it’s stuck around because it works. PTM can advise on which grade fits your equipment and cut it to your exact pattern. Call 01625 573971 or email sales@epdm.co.uk to discuss your requirements, or visit PTM to browse the full material range.
