What is the white powder that has appeared on my door stained with a Therma-Tru finishing kit?
We see this when the stainer has applied Therma-Tru stains very heavily (usually to achieve a dark color). There are UV inhibitors in the stain, which will migrate through the topcoat when there is a lot of stain on the door. Wash it off with detergent and water. It may come back one or two more times, but will eventually cease. To prevent in the future, use less stain. Most doors do not require heavy stain coats to achieve dark colors. Reducing the UV inhibitor will in the stain will begin reducing the durability of the finishing system.
