Most gasket applications are satisfied by various forms of synthetic rubber. Neoprene, NBR and SBR for example all work well when temperatures are below 200 °F. Above this, things get more complicated. If you have an application for hi-temp gasket material, here’s what you should know.
How Hot is Too Hot?
Gasket material specifications sometimes give a range for the upper temperature limit. This is because there’s no single temperature at which a material stops working. Instead, it breaks down gradually.
Heat hardens rubber and rubber-like materials, but time at temperature is as important as the peak value the material sees. Pressure is another factor: in a high-pressure application it might be prudent to use a material with a higher upper temperature limit.
Most commonly-used gasket materials top out at around 200 – 225 °F. If you have an application where temperatures are consistently above 225 °F consider exploring options for high temperature gasket material.
Hi-Temp Gakset Material: Elastomeric Materials
With a sustained temperature limit of 225 °F, EPDM is an elastomer that goes hotter than NBR, SBR and Neoprene. Most grades of silicone, fluorosilicone and fluorocarbon (Viton) gasket material will endure 500 °F, and 600 °F for short periods.
Hi-Temp Gasket Material: Compressed Non-Asbestos and PTFE
Compressed non-asbestos materials are composed of fibers, (mostly aramid,) in an elastomer binder such as NBR or SBR. The fibers provide strength and pressure resistance and the binder holds them in place.
Compressed non-asbestos materials are made in many grades and formulations but most will withstand up to 750 °F. In contrast, the limit for PTFE is 600 °F.
Very High Temperature Gasket Materials
Choices are limited for temperatures above 750 °F but one of the most widely used materials is vermiculite (a clay-like mineral.) This is either applied to a solid gasket or incorporated into a spiral wound gasket for pipe joints. Its upper temperature limit is around 1,800 °F.
Advice on Gasket Materials for High Temperatures
High temperatures are bad for many gasket materials. As gasket material suppliers of a large inventory of materials, ask us for a material quote if you need to seal hot fluids or in a hot environment.