After reading some comments on a model forum about acrylic paints and primers, I made up my own test. I sprayed Vallejo Gray Primer (V), Badger Stynylrex Gray Primer (S), Tamiya Flat FX-63 Panzer Gray paint (T) and AK Dark Yellow Primer (AK). I let them cure for 4 days.
The first picture is the four primers sprayed on white plastic and a toothpick pressed and dragged across all four samples. They all passed. The only issue was the tooth pick "polished" a line on each flat paint/primer but left the test primers undamaged.
The next picture is the after effects of doing the same test with a cut piece of plastic sprue. The Badger Stynylrex shows a little paint scrapped off. The rest passed fine.
The third test was using the end of a metal ruler. Only the Vallejo passed, while the Stynylrex did better than the Tamiya and AK. A result I did not expect.
The last tests were masking and "rip" off. First Tamiya Yellow tape was applied and burnished down like you would do when masking a straight line. Instead of pulling it off gently, I pulled it off with a quick pull. The AK pulled up along the line left by the mark made by the steel ruler. I think if the paint was not already been scratched, the AK would have been fine.
The final tape test was with actual cheap painters masking tape. Again, a quick pull and the results were a mess for the AK. The others test samples did okay.
What does this prove or show? If you let any Acrylic cure, you probably can handle without too much concern and not chip or scratch off the paint. You can tape it and certainly if you are gentle, you should be fine removing the tape.
This is far from scientific and the results would need to be repeated to prove that there was not an oily fingerprint that caused the AK Primer to scratch and then fail under masking. But I think it does prove that if you have been thinking about switching to Acrylic paints and primers (due to the smell, chemicals, clean up, etc), you probably will be safe and happy with the results if you take your time, don't scrape metal rulers over the paint, and don't use cheap painters masking tape! - Bob Walls