Donald,
There are alot of variables to that question. What type of paint job do you want? Durable, glossy, low cost, professional? A expert job would probally be done in a epoxy paint and primer specifically made for aluminum. Visit your automotive paint store and ask for recommendations from those guys. They can help with the durability and gloss and all the specific materials for aluminum. Or if you just want to paint your boat and it look ok, you could get all the materials and do it yourself. I painted mine using trailer paint from Tractor Supply and it's ok. Just make sure you clean and prep the boat very thoroughly. Scuff the old paint and wash multiple times to ensure a bond with the primer. Tractor supply also carries a primer specifically for aluminum. It etches any bare spots to prepare it for the paint. Lite coats and don't paint in the sun or wind. Hope this helps, and post some pics when you're done. Good luck. Rollcaster....................................