<P> Vacuum chambers can be constructed of many materials . "Metals are arguably the most prevalent vacuum chamber materials ." The strength, pressure, and permeability are considerations for selecting chamber material . Common materials are: </P> <Ul> <Li> Stainless Steel </Li> <Li> Aluminum </Li> <Li> Mild Steel </Li> <Li> Brass </Li> <Li> High density ceramic </Li> <Li> Glass </Li> <Li> Acrylic </Li> </Ul> <Li> High density ceramic </Li> <P> "Vacuum degassing is the process of using vacuum to remove gases from compounds which become entrapped in the mixture when mixing the components ." To assure a bubble - free mold when mixing resin and silicone rubbers and slower - setting harder resins, a vacuum chamber is required . A small vacuum chamber is needed for de-airing (eliminating air bubbles) for materials prior to their setting . The process is fairly straightforward . The casting or molding material is mixed according to the manufacturers directions . </P>

What is the purpose of the equalization chamber