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.
As a rule, use WEST SYSTEM higher-density epoxy fillers when bonding higher-density materials such as hardwoods and metals. Any of the adhesive fillers are suitable for most bonding situations. Your choice of a filler for general use may be based on the handling characteristics you prefer. Fillers may also be blended together to create mixtures with intermediate characteristics.
Adhesive Fillers vs. Fairing Fillers
WEST SYSTEM fillers are used to thicken the basic epoxy resin/hardener mixture for specific applications. Each filler possesses a unique set of physical characteristics, but they can be generally categorized as either Adhesive (high-density) or Fairing (low-density). Adhesive filler mixed with epoxy cures to a strong, hard-to-sand plastic useful in structural epoxy applications like bonding, filleting and hardware bonding. Fairing filler mixed with epoxy cures to light, easily sandable material that is generally used for cosmetic or surface applications like shaping, filling or fairing.
Epoxy Fillers and Epoxy Strength
While certain fillers will increase the density of epoxy, this does not correlate to higher physical properties or increased adhesion strength. Epoxy is strongest without filler added to it, but adhesive fillers are excellent for increasing the viscosity of the epoxy mixture, bridging gaps, preventing the epoxy from soaking too far into the wood, and preventing glue-starved joints. Fairing fillers turn the epoxy into an easily sanded fairing compound.
404 High-Density
404 High-Density filler is a thickening additive developed for maximum physical properties in hardware bonding where high-cyclic loads are anticipated. It can also be used for filleting and gap filling where maximum strength is necessary. Off-white colour.
