A Friend is painting the bottom of a Aluminum Fishing boat and was asking how to get the paint to stick?? I guess he is replacing the paint and (sprayable bed liner material) that was on there before, but it came off in large sheets!! I guess the Bedliner material was on there to help seal up the bottom.....

He mentioned some stuff called "Bottoms up"?? Anyone heard of it?? I guess it help everything adhere to the metal......

will need a etching primer for aluminum. what ever paint brand he uses have him ask the jobber, and make sure he tells them it's for aluminum.

later

Thanks!! He mention that he was going to use a Epoxy primer......Is that the same thing??

There is an acid wash you use before priming to clean and etch the surface. Get it at auto body paint store.

If you needs to have it acid washed Kruse has all the stuff. Why not have him powder coat it. Brad how is the boat coming along?

Aluminum begins to oxidize immediately after being dried off. You gotta use the proper cleaner (acid) then the proper primer. Some epoxies still need an undercoat of the aluminum specific primer. It's not expensive and the paint shop will hook you up. the critical part is getting the etching primer on the aluminum immediately after washing the oxidation off. Once the alum primer is on, you got all the time in the world to do the rest.

I generally have excellent results getting paint to stick to aluminum by painting something that is not aluminum and have over-spray contact the aluminum!

Mcolinstn has it with the immediate oxidization. Later is on with the etching primer. Good luck

Jon

You need to use Aluma-Prep. It is phosphoric acid (so be carefull with it) that etches the alminum and adds a phosphorus oxide that inhibits corrosion (to give you time to paint it). Be sure to rinse it VERY well, or any residual acid will bubble back up under the paint.

There are different opinions on which primer to use. Most recommend Zinc Chromate next, but the aircraft industry is shying away from that as there is some opinion that it actually helps start corrosion instead of stop it. I've been playing lately with "direct to metal" epoxy and so far like it, but have not tried it for continuous water immersion yet.

-Greg

(simonize) it's what they use on air planes
look into aircraft stuff