A Glossary of 122 Industry Terms –

In the world of gelcoat and resin, like every industry, there are terms used that are considered common-place. We have an extensive glossary to help with those terms. Have some others you think we should add? Message us and let us know!

A

Accelerator – An additive to polyester resin that reacts with the catalyst to speed up polymerization. This is required in room temperature cured resins. See Promoter.

Acetone – In an FRP context, acetone is primarily useful as a cleaning solvent for removal of uncured resin from applicator equipment and clothing. Very flammable liquid.

Additive – Substance added to resin mix to impart special performance qualities, such as ultraviolet absorbers, flame retarding materials (antimony trioxide, chlorinated waxes).

Air-drying – To cure at room temperature with the addition of catalyst but without the assistance of heat and pressure.

Alligatoring – Wrinkling of the gelcoat film that resembles alligator hide.

B

Bag molding – A technique for forming and pressure-hardening plastics or plastics laminates by means of air pressure, vacuum and/or heat in a flexible or semi-flexible bag or autoclave, usually in connection with a rigid die or mold.

Barcol hardness – A determination of surface hardness of a polyester using a Barcol Impressor.

Benzoyl Peroxide (BPO) – The catalyst used in conjunction with aniline accelerators or where heat is used as an accelerator.

Bi-directional – An arrangement of the reinforcing fiber strands in which half the strands are laid at right angles to the other half, a directional pattern that gives the maximum product strength to those two directions.

Binder – A resin soluble adhesive that secures the random fibers in chopped strand mat or continuous strand roving.

Blister – A flaw or air pocket between layers of laminant or between the gelcoat film and the first layer of laminant.

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