This thread reminded me of a blushing issue I had decades ago at my motorcycle shop, not with base, but with Dupont clear lacquer.
I had countless hours invested in murals, gold leaf and striping on a full custom street/show bike, all done in lacquers, and began building up clear late one night, as always with clear, using the slowest thinner (I believe it was 90). Looked great when I left the booth, and I drove home in a pea soup fog. The next morning the clear had blushed. I freaked, fearing I'd have to strip the entire job and begin again. I'd developed a relationship with the Dupont chemist in charge of their Imron division, so called him and he said to just hit it again with more clear when humidity was down. I did and the blushing disappeared....The additional lacquer had melted into the blushed layers. I continued to build with many thin cotes of lacquer and all was well.
After this close call I paid attention to humidity in the air, not wishing to repeat the experience. I used lacquer for my "show" bikes, but had gone to Imron clear for most of the street bikes due to it's durability and resistance to gas spills, etc. I now knew the solution when shooting lacquer, but was concerned that if the blushing happened to Imron clear, shooting another cote wouldn't save the project. Fortunately, I never had need to find out...
My question..., Is blushing due to temps/humidity ever an issue with modern clears?
Thanks,
Lance