Abstract: Methods are disclosed for forming silicone rubber vacuum bag assemblies which can be used repeatedly to debulk and autoclave composite layups. These bags can be formed of a single layup of uncured silicone rubber over a tool of a simple shape or as a layup of uncured silicone rubber over the totality of the tool and a prepreg consisting of a fiber in uncured silicone rubber laid up over areas which do not include male and female radii on the tool. Additionally, a further bag can be constructed by removing those portions of a simple bag which overlay recesses and female radii followed by curing of the silicone rubber and filling of the recesses within uncured silicone rubber followed by a second cure period. Each of the vacuum bag assemblies of the invention is postcured preferredly removed from its defining tool so as to stabilize and fully shrink the silicone rubber. The vacuum bag assemblies are mounted in a silicone rubber membrane which is preferably then supported in a frame.