Tips For Polyester Resin Infusion

Polyester resin infusion can be an easy process, yet there are still several tricks involved. While less complex than epoxy, planning ahead for polyester resin infusion is still vitally important if it's to go smoothly. Fibre Glass Fabrication and Repair Similar to open molding, there is much to keep in mind such as mold release systems, skin coats, in-mold coatings (if applicable), resin systems and infusion materials.
Infusion generally involves placing dry stacks of reinforcements and core materials into a vacuum bag, extracting excess air through pumping out and wetting out, then pouring a resin solution through to wet out the pile. Once complete, your finished part should have low void contents with smooth pinhole free surfaces - ideal qualities of success for part manufacturing!
Infusion may cost more than wet layup, but it can save both time and money when used effectively. Plus, its cleaner process means less mess - plus being able to use either polyester or vinyl-ester resin makes it an attractive alternative over epoxy only processes.
One key point when planning infusion is to remember it must be conducted at room temperature; although cold weather infusions may still be carried out with some preparation. This is because resin and infusion materials will cure and flow more smoothly at warmer temperatures. Epoxy has an increased viscosity when cold, which requires you to select an infusion material with high temperature tolerance. Woven and stitched fabrics tend to be more suitable for resin infusion than unidirectional fabrics, as their weave creates natural pathways for it to move through the material. Some manufacturers even provide reinforcements with extra stitching or wider spacing of fiber bundles to facilitate resin infusion through their material.