Will a 2nd layer of POR15 stick without sanding?
What he said...yes if you follow instructions. wait for the first coat to get draggy to the touch (around 3hrs depending on atmospheric conditions)
I may have waited a bit too long, as it was still too wet for a second coat when I went to bed and was past the 'squeaky drag, but no paint on finger' test the next morning. I did not sand, can hardly reach it one-handed, I just slathered another coat in there and am calling it done.