Little tiny bubbles appear later in nitro finish

So on a handful of the guitars I've finished, I have ended up with what looks like the fizz in 7up... It wasn't there right after the lacquer was sprayed, and it probably just wasn't noticeable before I buffed it (although I didn't notice it right after buffing it). I think what's happened, is that somehow these tiny bubbles appeared, then when I ran the buffing compound over the body, it got wedged into the tiny bubbles, making them noticeable... It's not over the entire body, just certain areas. This body got it the worst so far, you can see it near the waist and on the upper horn. It almost looks like sand sprinkled on the body...
http://i993.photobucket.com/albums/af58/andrewlovesgrunge/IMG_9870.jpg

What is this from? How can I prevent it in the future? It didn't occur anywhere else on the guitar except that streak in the front...
http://i993.photobucket.com/albums/af58/andrewlovesgrunge/IMG_9874.jpg

And it wasn't there immediately after spraying (like blushing?)
http://i993.photobucket.com/albums/af58/andrewlovesgrunge/IMG_9087.jpg

Or even immediately after wet sanding and buffing (14 days after spraying)...
http://i993.photobucket.com/albums/af58/andrewlovesgrunge/IMG_9132.jpg

It's like it started appearing a month after spraying it... The guitar hasn't been in direct sunlight, either...

I use Mowhawk nitro, and I'm spraying in perfect sunny SoCal weather (about 2 miles away from where Fender is spraying their guitars- although they're of course in a room with controlled climate).

Don't know exactly, but here are some guesses -
- somehow when you applied the finish in particular areas you did something that causes a bit of air to be mixed in, which started to work its way out as the finish cured, hence bubbles. Are the places with bubbles, say, the first place you sprayed, the last place you sprayed, the place where you started again after taking a break? Look for something different about what you did in those places. Are the bubbles on different pieces in similar places or different places?
- there's some chemical reaction going on at certain places on your piece that is evolving gas. Is it possible that you left some chemical in place at those places during preparation?
- is your application gear distillery-clean (distilleries are often cleaner than operating rooms)?

I wonder if there were minor imperfections in the surface prior to spraying. Before a 'full cure' they were buried. Now after the wet sanding and polishing process and a full cure, the finish has become thin enough to reveal them.

I've had this happen when my grain-fill step wasn't as good as it needed to be.

Just a guess, though. I'm thinking in this direction as I don't know of a way that 'bubbles' could appear after such an extended period of time.

Disclaimer: I'm no expert and my experience is based on just a few projects I've shot with nitro. Hopefully some of the 'pros' will chime in here...

There's some information which might be helpful here:

http://www.reranch.com/101a.htm#Troubleshooting

Your coats are a little too thick, I've had this happen before. It's outgassing that gets trapped. Shoot a bit lighter and it should not happen again.

Your coats are a little too thick, I've had this happen before. It's outgassing that gets trapped. Shoot a bit lighter and it should not happen again.

+1

I have also had this happen when I was shooting in hot weather. The lacquer dries so quick on the outside it traps the gases.