PPG clear Question

Yea I wet sand it & buffed it out. The ppg 4000 clear doesn't get reduced. They told me that if you reduced it, it could lead to solvent pop. It looked good when I was done. I looked at it the next morning & wow it was ruff. The temp. was 74 that day. I got the hardner for that temp. I sprayed a door & quarter on a car with the same clear & it turned out beautiful, very smooth. The air temp was the same but used different hardner temp & I did give it a splash of reducer & mean I very small splash, the last coat of clear.