Bagging film

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 non-woven synthetic felt placed over the release film inside a vacuum bag to maintain a continuous air path across the whole part, so that vacuum is drawn evenly, and to absorb any resin that bleeds through. It is discarded after cure.

A tacky butyl rubber tape used to seal the vacuum bag film to the tool flange, or to itself, forming an airtight envelope around the laminate. Grades are chosen to match the cure temperature and to release cleanly from tooling afterwards.

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.