I thought I would pass on an observation I made.

A couple of months ago I painted a metal railing using Rustoleum gloss black. I took my finger to it a few days ago and found I could still scape it. Now this was during the day with the sun on it. It should have cured as much as it would by now. The other night I was on the deck and tried to scape the same spot and it was rock hard. It dawned on me that the heat of the sun softens the paint. Now I have put parts I have painted with this paint in the oven to cure after painting with good results. What I would suggest is that when one goes to polish the paint do it out of the sun where it is cool. The paint will be harder and you should have better results.