Tiny bubbles
 

And not in my champagne.

As part of my restoration, I'm sanding the paint off the steering column's outer and inner housings and painting them matte black with Wurth spray paint. I'm hand-sanding down to primer with 220 grit, followed by 600 grit.

I sprayed the outer housing first, and it came out perfect. I did 4 light coats.

But when I sprayed the inner housing, I got tiny bubbles everywhere. It looks terrible. I prepped both parts identically, and they are made of the same material. Why did this happen? How does one prevent the bubbles?

I answered my own question by keeping at it until it worked. I think it was a combination of not shaking the can long enough, and too heavy a coat. The third try was the charm.