Beater-addition gasket materials, or simply Beater Add for short, are made by proprietary manufacturing processes. Each Beater Add vendor has their own process but the general process is as follows: A select mixture of water, latex, fibers, fillers, and chemicals is formed into a slurry. The slurry is then run through specialized machinery that extracts the water, dries the mixture, compresses, and vulcanizes the material into a long continous sheet. Sheets are rolled as a finished product from which gaskets are fabricated.
The selection of fibers, fillers, chemicals as well as the compression force produce a wide range of formulations. The main advantage of Beater Add is that it is inexpensive. A disadvantage is that operating temperature ranges may be limited.