For low-pressure applications which demand a thin-line, contact-type seal due to weight or space limitations. Metal thicknesses range from .010" to .031", depending upon kind of metal and corrugation pitch. Thickness under .010" may rupture when corrugated. Minimum of 3 concentric corrugations are suggested for each gasket face, although there are successful applications using only one. A slight flat within the inner corrugation and another beyond the outer corrugation serve to stiffen the gasket and are recommended when space permits. Optimum performance requires corrugations on both gasket faces instead of being embossed on only one face. Corrugation pitch for other #300 applications may run from .045" to 1/4", while overall gasket thicknesses will vary from 40% to 50% of corrugation pitch. Temperature ranges depend on metal used. Pressure limit, 500 psi.

This is the #300 with cord cemented into the corrugations. Metal thickness is about .019" or .020". Corrugation pitch is 5/32", 3/16" or 1/4", according to gasket width or application. Approximate overall gasket thickness is 65% to 70% of pitch. #305 is a highly effective replacement for millboard gaskets on large-diameter flanges which handle flue and combustion gases at temperatures up to 1150 deg F (depending on the metal) under light pressures. Frequent breakage is a recognized problem in the handling of millboard gaskets. #305 gaskets withstand pressures to 600psi. They are not suited for vacuum or oil service.