West System® 407 Low Density Faring Filler. A blended microballoon-based fairing filler for West System® Epoxy. Add to a mixture of epoxy resin/hardener to create a faring putty. Easy to sand or carve once cured. The higher the percentage of 407 in an epoxy mix, the easier it will be to fair. Reasonably strong on a strength-to-weight basis. Designed for faring, carving and thickening. Can be blended into any West System® 105 Epoxy Resin®/200 Series Hardener combination. Cures to a dark red/brown color. Red/Brown. 4 oz.