When i was preparing for a blast job on my Brookville roadster body to get rid of that crappy red oxide lacquer primer I called PPG to ask about techniques, etc. They said not to use soda blast as it left a coating on the metal that was difficult to remove and paint or primer wouldn't adhere to it properly. They said either use plastic media or sand. Dave
Bah.....thats why you wash of the metal with prep all or a water vinegar solution. Soon as the metal is dry.....prime it and seal it.
I also had to remove the lacquer primer from my Brookville, called PPG about soda blasting, and also, at first, was told not to. The problem is many people do not take the time to simply water wash the soda residue before they shoot primer, so it's is easier for PPG to tell them not to use soda. I had mine soda blasted, and will use it again to remove paint and surface rust in the future. Plastic and glass would have cost about 3 times the price of soda in my area, with more cleanup, and I wouldnt even consider sand to remove paint or primer from any body metal, much less a brand new Brookville! Three big advantages of soda: cost, long storage rust protection as long as the parts are kept dry, and very easy preparation for primer/paint. IMO.
Don't like sand? Well all I can say is that maybe I know a more skilled blaster than the one you have seen! I can't find any appreciable problems! Mine is in gloss black, I once metal finished in a GM plant on new cars, and I don't see any problems. Dave
Was told by 2 painters about paint not sticking after soda blast. They did do all the cleaning of residue as best as possible. The problem is it gets in to places that are almost impossible to get to and thats where paint problems start. If your doing a whole car, (inside, outside, underneath), it's going to get into places you wouldn't think would make a difference until after shotting paint. Inside of window regulator area, boltholes that have threads but closed on the backside, inbetween seams, between frame rails (unibody rails) and floors, under dash areas. Just what I was told and passing it on. I've never used the stuff but heard alot of good and bad about it. I don't see that there would be a problem if doing outside panels and can get to them to get good and cleaned. Of course, if you don't get sand dust residue cleaned, you would have the same problems. It seems the other options are a little pricey.