Speedokote epoxy primer/sealer (white)

I'm curious as to how many of you guys have used this product? And your opinion of it. Also what is a good starting point for air psi at the gun? Someone suggested 8-10 lbs? That seems pretty low to me. Especially since this stuff is pretty thick. I'm doing door jambs and small areas so I'm using a small harbor freight siphon type touch up gun. I know it's not the best but I'm on a tight budget and it's what I have. This is my first project so I will probably be asking more questions later. Thanks in advance, Lits