Q: Will powder coating temperatures affect the strength of forged wheels? A: There is a lot of misinformation out there, both for and against powder coating forged wheels, so to get to the bottom of it, I went straight to the source. Craig, a technical veteran of 25 years with BBS Wheels, was kind enough to shed some light on this issue. Craig has seen a fair number of powder coated wheels crack over the years (uncoated wheels, too). The main reasons he cited for wheel failures with respect to powder coating were 1) abusive stripping practices, such as using a burn-off oven (generally 700-900*F) or hot sand stripping to disintigrate the originial finish, 2) poor process control, such as ovens with large temperature swings, inaccurate thermal control, or infrared heaters that bombard the parts with heat to accelerate the process. These elevated temperatures over-age the heat treatment of the alloy, increasing its brittleness and making it more prone to crack, and 3) repeated stripping, coating, and heat cycling over a wheel?s lifetime. Craig also added that the factory finish on BBS wheels consists of a powder coated base coat with liquid top coats. The powder coating temperature and dwell are considered in the manufacturing process and are tightly controlled.
