Breather

A consolidation technique in which a laminate is sealed under a flexible airtight film and the air is evacuated so that atmospheric pressure compacts the plies during cure. It removes trapped air and excess resin and is used with wet lay-up, prepreg and infusion processes.

A thin polymer film, often perforated, placed between the laminate and the breather in a vacuum bag stack. It prevents the breather bonding to the part, while the perforation pattern controls how much resin is allowed to bleed out during cure.

The flexible, airtight polymer film that forms the outer membrane of a vacuum bag, sealed to the tool with sealant tape. Films are selected for cure temperature capability, elongation and puncture resistance, and pleats are added so the film can conform to the part without bridging.

A sacrificial woven fabric laminated onto the surface of a laminate and torn off after cure, leaving a clean, uniformly textured surface ready for bonding or painting. Release-coated variants can transfer contamination and are generally avoided where structural bonding will follow.