AChipmunk,My sandblater uses coares sand ,I picked it up as soon as he finished it ,and it had a good bare metal rough finish not smooth wich I would think would be good.
I had the first coat on withen an hour .and then applied another coat before first had hardend.
I have the frame on jack stands and covered up with sheets to keep the sun light off of it coming through the windows.
I was going to put my dropped axle on today ,and noticed how you can see the rust in several area's coming thru the POR-15.You can take a paper towel and wipe over it and see the rust on the towl.I live in Houston Texas where it is very humid but I wouldnt think that would have anything to do with it.
I guess I will have it blasted again and have it primed and painted .I hate to spend the money to have blasted again and painted ,but I dont want to take chance of this happening again.