Vacuum Bagging - Vacuum Bagging -. This molding technique is performed by drawing a vacuum into a cellophane or polyvinyl acetate bag draped over the part.. Using multiple layers of fiberglass, carbon or Kevlar material this method achieves the highest strength to weight ratio in the composite. Vacuum bagging forces out air and excess resin from the lay-ups, minimizing emissions and maximizing reinforcement content.

Hand Lay-Up – The oldest and simplest molding technique. Reinforcing materials and catalyzed resin are laid into or over a mold by hand. They are then compressed with a roller to eliminate entrapped air.

Spray-Up – A spray gun is used to simultaneously deposit fiberglass and catalyzed resin on a mold. This is the fastest open mold process. It is used for a high production runs on larger parts, such as showers enclosures and tubs.

RTM – Resin Transfer Molding (RTM) is an injection molding process whereby catalyzed resin is transferred or injected into a closed mold in which the fiberglass reinforcement has been placed. RTM offers many advantages for production volumes of 500 to 10,000 parts per year.

Resin Infusion or “Light RTM” – Is when a vacuum is created in a closed mold and the resin is then injected ino the mold. Because of the vacuum, the resin fills every available space, eliminating air voids, thus creating a stronger, integral product.