Q: We are a powder coating shop in the upper Midwest United States and have been experiencing a hazy appearance on our black semi-gloss powder coating finish after the parts exit our oven. We use an electric batch oven. Could our powder supplier be putting too much wax in the coating?
A: Please check for the correct exhaust in your oven. Operators of electric ovens often completely close off the exhaust because they are not worried about byproducts of gas combustion.
Most powder coatings emit a low level of volatiles upon baking, even in electric ovens. These volatiles (mainly water and low-molecular-weight additives) create smoke and can condense on the surface of parts in the oven, causing a haze. Opening up your exhaust vent will surely allow the low level of volatiles to escape, thereby keeping your parts haze-free.