I used white pigment in the epoxy to coat the inside of the hatch compartments on a CLC plywood boat. I wanted something that would not be a dark hole when rooting around for gear. I thickened the epoxy mixture with cab-o-sil to the consistency of thick whipped cream and painted it on. It turned out great. After using a two part polyurethane on the outide of the hull, I would try the epoxy coating next time. Mix the pigment in the epoxy first to make sure there is enough tint. Add the hardener and cab-o-sil next. One caution is to do it when you have a lot of time. It will look smooth and shiny at first, but as the epoxy heats up as it cures it will start to run on the vertical surfaces. Keep brushing the runs out until the epoxy sets enough to hold firm. I used a slow cure epoxy and the brush marks all filled in. Don't have a technical reason for using the cab-o-sil. It was my first try and I was experimenting. Even blind pigs find acorns!