West System 405 Filleting Blend When mixed with a 105 Resin Epoxy/Hardener mix the 405 Filleting Blend is excellent for filling epoxy joints or fillets on naturally finishes wood. Featuring strong bonding properties, a natural brown/wood tone color, and requires very little sanding.405 Filleting Blend is a fairing filler. Meaning it cures into a light er and more easily sanded material. Generally used for surface applications such as shaping, filling, fairing, or cosmetic applications. All faired surfaces should be sealed with epoxy before painting. West System 405 Filleting Blend is best suited for bonding fillets with epoxy. It creates a smooth and strong bond that acts as a structural brace between parts. It also helps increase the joint bonding area.Click Here to download 405 Filleting Blend Safety Data SheetFilletingA Fillet is a continuous bead of thickened epoxy mixture that is applies to an angle created between two parts. The purpose is to increase the surface area of the bond and act as a structural adhesive and brace. Filleting creates a glue joint that requires no fasteners and can result in a joint as strong as the parts being joined together.