West System Manuals

WEST SYSTEM 407 Low-Density Filler Technical Data Sheet

The 407 Low-Density Filler is a blended microballoon‑based filler used to make fairing putties that are easy to sand or carve. It provides a reasonable strength‑to‑weight ratio and cures to a dark red/brown color. The filler is added to epoxy resin/hardener mixtures to achieve the desired consistency for various applications.

The sheet includes a guide for selecting filler consistency, showing how the amount of filler controls mixture thickness. A chart gives typical properties for cured epoxy at different consistencies (e.g., Shore D hardness 63, compression strength 2,900 psi, density 35 lb/ft³) and lists the quantities of filler needed for each package size. A filler selection guide ranks the 407 among other WEST SYSTEM fillers for uses such as bonding, fairing, and laminating.

Covers: Technical Data · Filler Selection Guide · Mixing Guidelines · Consistency Guide · Properties