I have a touch up spray gun and have sprayed a few panels with success. last night I was spraying 1 shot Primrose yellow. Thinned it half and half with mineral spirits, plus added 10% 1 Shot catalyst. pressure at 45 lbs. Spraying onto a white panel...scuffed it then wiped with Rapid prep. Got some severe runs. Didn't spray any different as far as method while spraying. Wondering if certain colors, like this Primrose Yellow are thinner to begin with? Now what? As of 10 am today it had been on 12 hours. Should / can I sand it to knock down the runs, then respray? If so, what grit and can I use my Makita random orbital sander? Suggestions on the percent of thinning, pressure, etc.? I'm hoping someone will come through...thanks ahead of time!! Mick