Our boom, original to the boat, is looking pretty shabby. Is it OK to pull everything off and sandblast and powder coat the boom tube? Any disadvantages to powder coating over just painting?

Powder coat is actually the preferred finish that new aluminum spars are made with. It is more durable than painting. Properly preparing by sand blasting as you state is the right way to go. When I had Rhapsody I didn't have access to powder coat resources so sanded and painted the boom.

Thanks, that's what I thought. Found a guy local to me that did my winter rims for my car fairly cheap and they turned out great. He has a pretty large oven, so I do think it would fit.
I do need to pull the out haul out anyway and rework it. So this will be a good time to pull everything and get it done right. Thinking new decals on both sides too.