honestly this whole scratch test thing is not a valid test. if you've ever painted single stage yourself, you'd know it takes months for the paint to dry. actually putting the windshield in on my 71 blue beetle in the pics about 2 months later, i put a rag on the front cowl to rest the window on while i'm putting it in and also for leverage when putting it in, and just pressure from that left a perfect imprint of the rag fibers in the paint. paint takes time to dry. i really think that your test peice is not a good representation of the finished product. your welcome to come and try to scratch my 6yr old and my 5month old paint job, but only with your finger nail!!! i can tell you that for the first 2 months i too could probabally have for sure scratched off my paint if i did try. but the same could be said of any true automotive paint job. as far as the reaction to the paint or bubbles, you defineatly need to clean the surface really good. no matter how good any paint is it won't stick if there is any residue. as for sticking to bare metal, that's what the paint is made for, says right on the can, i have had 0 (zero, nada, nothing, zilch) issues with bonding/adhesion, reactions, scratching, remaining soft, ect with this paint at all. i can comment on one time that a teradactial crapped on 2 of my cars, 1 being the 74 beetle orange and the other being my 1999 gmc sierra, and the same load of poop hit both cars (real world expirement, 1 bird, same poop, 2 cars!!!), and it baked in the hot sun for a day before i noticed. the bird poo dried so hard, i used bug and tar remover and soaked it a bit and it came off the beetle without leaving any marks, but permanantly stained and damaged the BC/CC on the paint on my 1999 gmc sierra, this was about 10 months after painting the beetle. so i can say it is highly resistant to teridactial poo in mass quantities, that load completely wrapped around the whole car and actually stained the rubber on the running boards of the beetle and the plastic on the 99 sierra.