PL32 Hylomar, Aerograde, Gasket and Jointing Compound Non Setting Universal Jointing Compound Resistant to Fuels and Lubricants Use on Gaskets and Metal Surfaces Non Flammable Compound Original Blue Hylomar 3.5 Ounce Tube Hylomar Aerograde is a highly engineered, polyester-urethane based non setting and non hardening gasketing compound, for use in the aeronautical industry. Hylomar Aerograde was developed in conjunction with Rolls Royce-Aerospace Division for sealing joints in jet turbine engines. Hylomar Aerograde can operate from approximately -50 degress centigradeto +250 degrees centigrade.