Filler Selection Guide

WEST SYSTEM Epoxy fillers are used to thicken the basic epoxy resin/hardener mixture for specific applications. Each epoxy filler possesses a unique set of physical characteristics, but they can generally be categorized as either Adhesive (high-density) for bonding applications or Fairing (low-density) for sanding and fairing applications. Adding these filling agents to blended epoxy resin and hardener allows you to control the consistency of the epoxy, bridge gaps in joints, create either strong or sandable fillets with epoxy, or alter the cured density of epoxy making it easier to sand smooth.

Adhesive Epoxy Fillers

Adhesive fillers are suitable for most epoxy bonding situations especially with high-density materials like hardwoods and metals. Adhesive filler mixtures cure to a strong, hard-to-sand cured epoxy plastic useful in structural applications like general bonding, filleting and hardware bonding.

Fairing filler epoxy mixtures cure to light, easily sandable material that is generally used for cosmetic or surface applications like shaping, filling or fairing. Seal all faired surfaces with epoxy before painting.

Epoxy Additives

Additives are used to give epoxy additional physical properties when used as a coating. Although additives are blended with mixed epoxy in the same two-step process as fillers, they are not designed to thicken the epoxy. See Additives & Pigments. Follow the mixing instructions on the individual additive containers when blending these products into your epoxy resin/hardener mixture.

General use filler selection may be based on the epoxy handling characteristics you prefer. Fillers may also be blended to create epoxy mixtures with intermediate characteristics.