Duralux also makes an aluminum boat paint that you use without a primer. I painted a mud boat 3 yrs. ago and it's holding up great. Like
slimhogdog said, I used the aluminum brightener acid to clean and etch the bare aluminum , rinsed well, let dry and then painted with the
Duralux Marine Aluminum Boat Paint. Here in Morgan City you can get the aluminum brightener acid and Duralux Marine Paint at any hardware store. If you can't find it, you might have to order it. I pasted a link of the paint below. You should be able to get it much cheaper.
http://www.bottompaintstore.com/duralux-aluminum-boat-paint-green-gallon-p-10802.html 
