Hi, I’m dne’, I’ve retaken the roof on my ’67 Mustang back down to metal (rust or whatever is on my roof), I had painted it and it was beautiful, now I”m having to start all over again! I’ve sandblasted the roof cause nothing else would remove what was on it. Do I use etching primer first, then epoxy. I have Eastwoods epoxy primer, but I was told to ask an Eastwood tech whether or not to use etching primer first or just use epoxy primer over exposed metal.?