One of the things I enjoy most is testing and it is on going and here is a good general spray test with epoxy.
First, the 55-gallon drums you see in the picture are our empty's right now there are 94 of them and when we get 150 to 175 we call the certified drum recycler.
Now for how I do all batch testing.
The black drums are solvent drums, blue drums are polyols and the reds are Iso's.
I NEVER clean the drums, I don't sand the drums all I do is dust if needed and spray.
The epoxy I sprayed two wet coats without flash time between coats and you will notice in one spot I tried to run it. Success!!!
This was yesterday at 80 degrees and 85% humidity.
Not one solvent pop but I had 157lbs at the wall gauge and 28Lbs at the gun, using Iwata LPH400 with a 1.4 tip.
Normally solvent pop is caused by too low air at wall or gun and dry spraying.
For the 2 coats, average mils are 1.8 to 2.2 not counting run area.
18 hours later I have 85% adhesion and that is right about where the epoxy should be BUT that is with no prep and also all the black drums come with .04 mils of paint.
just fun play time though you might be interested.