Seeking Powder-compatible Filler

Q. Do you know of any type of filler material that can be used to fill in holes or surface imperfections that would work with powder? I run a powder coating line and apply powder manually using a box feed system. It is baked on with a conventional gas-fired oven. We have some parts that have rough areas that we need to smooth out. So far, we have not found any good filler for powder.

A. Spectrum Powder Manufacturing Ltd. offers a heat-curable sealant designed for use with powder coatings. The vinyl caulking fills voids and seams on steel and aluminum substrates and can handle the normal range of powder cure temperatures (350° to 400° F).

Another product that can be used with powder is Thermobond-3, produced by Dura-Chem Inc. It is fairly easy to apply and can be sanded to a smooth finish.

Some coaters also use Lab-Metal, available from Alvin Products. They offer different products for higher temperatures that will survive the powder cure range.

Any filler should be tested in your process to make sure that you are using it correctly and that it will work for your products in your system.