The last time we painted with POR-15, we did both coats in black. This time we did the first coat in silver and the second in black. We thought two colors would make it easier to get proper coverage with the second coat. It was easier to see exactly where we had applied the first coat, but the black over silver did not coat as well as the black over black. The silver and black POR-15 are different. The consistency is different, the coverage is different, the results are different. The black did not seem to want to stick to the silver. It felt like we were just pushing the paint around. Although it did level out, the end result is not pure black like the passenger area of the car, and the finish is no where near as flawless-looking. In the end we wish we would have stuck with the black over black method. Part of the problem was the black bubbled in spots. We think it might have been leftover residue from the car's original seam sealer that had some kind of reaction with the silver POR-15 that caused the black to not adhere to the silver as well. We did not have this bubbling issue with the black over black, and there was leftover seam sealer residue there as well. We used 2 1/2 cans of black POR-15 tonight, so we did end up using the same amount as the silver.
After we finished painting the second coat of POR-15 in the car, we painted the speaker mounting plates we had previously cleaned and prepped. We did these in black only. We determined it is easier to paint with the black POR-15 than the silver, and painting these last pieces reaffirmed what we already thought.