Gathering vacuum bagging supplies is the first step in this innovative clamping system for laminating a wide range of fabrics, core materials, and veneers with epoxy. Vacuum bagging uses atmospheric pressure to deliver firm, even clamping pressure over the entire surface area of a composite part or repair, regardless of the material or materials being laminated. By laminating over simple molds, composites can be molded into an endless variety of functional shapes. WEST SYSTEM vacuum supplies can be purchased individually or as a complete kit.

What materials do I need for vacuum bagging and how do I use them?

Let’s dive deeper into what materials are used in vacuum bagging and how to use those materials to achieve a great composite part. The materials and how to use them will be described in the order they should be put down on the mold or laminate.

Sealant tape

Lay down a layer of sealant tape around the perimeter of the part, leaving some space between it and the laminate. The area where the tape is put down should be clean and free of epoxy residue and stray fibers. Sealant tape is also commonly referred to as tacky tape or mastic sealant.

Release fabric

Release fabric should be laid directly on top of the wet laminate. Release fabric leaves a textured finish when it is removed, reducing the need for surface prep before secondary bonding. Release fabric is commonly referred to as peel ply. The most common types of peel ply are made out of nylon or polyester fibers. Some peel ply is coated with release agents.

Release film

Perforated release film is a thin plastic with small holes that control how the excess epoxy moves from the part to the breather fabric. This is an optional layer in the vacuum bagging process.

Breather fabric

The function of the breather fabric is really two-fold. As vacuum pressure consolidates the laminate, the squeezed-out epoxy goes through the peel ply (and the release film if you are using it) and is absorbed by the breather fabric. Because of its open structure, air flows easily through breather fabric allowing the air to be evacuated from the consolidated laminate. Breather fabric is also referred to as “baby blanket.”—Excerpted fromVacuum Bagging Basicsby Rachael Geerts, Epoxyworks 49