For a gasket to do its job effectively, it is essential that the seal it creates remains intact over a long period of time. The gasket must also be resistant to fluids and/or gases and withstand the operating temperatures and pressures to which it is subjected.

For many applications, these qualities are best achieved with adhesive gasketing products in preference to pre-cut compression gaskets.

Adhesives brand Loctite says the main reasons why compression gaskets leak or fail are poor surface contact and their tendency to relax under load and decrease in thickness, with subsequent loss of bolt tension in the flange joint. High stresses on the gasket can also cause it to crack, tear, rupture or to be squeezed out between the flanges.

“By comparison, a liquid gasketing product fills all voids to create a perfect seal between components, with maximum face-to-face contact, eliminating flange face corrosion. It has high resistance to solvents, resists high pressure when cured and there is no need for re-torquing. A wide range of adhesive gasketing products are available for different flange types, gap sizes and material, but careful consideration of the performance criteria is essential.”

The company cites the example of a manufacturer of cast iron gearboxes and geared motors that had opted for liquid gasketing on the adapter assembly flange but was suffering poor sealing that resulted in a 5% leakage rate. The adhesive used also also made it difficult to dismantle the geared motor for maintenance and repair.

This manufacturer switched to Loctite 518, which effectively fills the gaps between the flange surfaces and cures quickly, allowing instant pressure testing to 40psi. Leaks have now been eliminated and disassembly is easier for customers.