New to forum and the paint biz. I recently purchased a quick dry alkyd primer sealer to do my deck from a local paint co. On the can it says no thinner needed, though as I attempted to apply it was drying too quickly and was such a heavy paint, very thick it started to clump up. After several tries at applying I decided to try thinning and did a sample on a used piece of same wood. I am not sure what would be the recommended thinner but I had some naptha on hand. seemed to lay out so much better, though I am concerned as to whether it would break down the oil based paint too much. I am preferring a second opinion as to the dealers input at this time. Any help would in this matter would help.