Hey guys, so I refinished a guitar for the first time recently, and it was only 35 to 50 degrees in the garage at any given time. I used Minwax semi gloss polyurethane, which I thinned to be able to wipe it on. The guitar looks good by my standards, but the problem is that after a little more than a month I can still dent the finish with my fingernail. Will it cure eventually? Or do I have to start over (again)?