I am about to do a 20ft. box truck and it just so happens on the first one I get the whole box has been sandblasted and there is a powdery residue left on the surface. It will be a full wrap but I am kind of leary about it adhering properly to the surface. Has anybody had this experience? I thought that primer may help but there is no way in H**l I can primer a 20ft box that would be crazy. The reason it was sandblasted was because there was old cracked vinyl on the truck before they bought it. What do you guys and gals think?