spars is a lost
cause. No matter how careful you are in the application and use, it will look like bad within a very few years. You'll get scrapes, abrasion, nicks and bubbling from galvanic corrosion
around fasteners and hardware
. That is using the proper aluminum paint
system with it's exacting multi step process. Just watched two guys work 8-10 hours a day for more than a week prepping and painting an aluminum mast that they'd done only 5 years before.
Powder coating is a non starter. Any break in the plastic surface allows corrosion
to work under the coating. Within a short time, the powder coat is coming off in sheets
. Powder coating is a boon to the manufacturer cause it looks pretty and gets the product sold. Unfortunately, it begins to look like crap in a very short time because of creeping corrosion. It's especially bad around salt water
If it was me, would leave the boom naked and let aluminum's naturally forming surface corrosion protect the metal.