finally my 308 is in the paintshop. I had it sodablasted so there was bare metal on frame and body. I had the frame painted with POR 15 hoping that it would provide rust protection, turns out that on the areas where the metal was smooth like new the POR15 can be peeled off like a thin film, which is what usually happens when the surface wasn't sanded prior to painting. I had the wheelwells additionally covered with undercoat which actually looks quite subtle and appears to ne very strong. My thought is to cover the entire frame with a coat of undercoat which won't look a clean as what I have now but it would potentially protect the frame better. what are your thoughts? Good idea or blasphemy? Thanks, Helmut
POR15 is one of the best coatings that I've ever used. Properly applied to a well prepared surface, it's practically like powder coating once it's dry. I've left a paintbrush on a paper towel on my steel benchtop that needed to be pried and scraped off when it dried. It thoroughly bonded to the steel unlike a typical paint. Surface preparation is extremely important for a good bond. It is recommended that you use water-based Marine-Clean to degrease everything and rinse with water followed by an acid-etch treatment with Metal-Ready (phosphoric acid/zinc phosphate) and rinse with water and dry completely. They are very specific about this preparation and specifically caution against using solvents to degrease. I suspect that your surface wasn't completely clean and dry.
That's what I expected from POR 15, a exceptionally good protective coating. Considering it was so hard to get off your steel workbench makes me hope that the paint shop actually used POR15, it certainly peels off on some areas without much scratching required.
I'm sure there are others here who know much more about this than I, but I've read a bit lately on other forums regarding soda blasting and difficulty with paint adhesion afterward. Apparently the soda leaves a residual coating that must be removed prior to painting. Seemed to me they were washing the blasted components with something to remove acidity prior to finishing. Sorry the only link I could find quickly was this one, about half way down on the page they talk about using a water and vinegar rinse to neutralize the soda... http://www.trifive.com/forums/archive/index.php?t-3662.html
thats some good info, thanks! I was hoping that the sodablast company who did the job (CalBlast) would know about how to clean up the residue from the soda, since they were the ones who also sprayed the POR 15.
