Ok, I'm looking for information on painting my aluminum Grumman canoe. I have had to boat for many years and have used it for waterfowling but as usual after a bit the spray paint that I had applied comes off and the it looks pretty crappy... Is there anything that can be applied to the aluminum to help paint adhere to it?
I have never painted an entire aluminum canoe, but I’ve painted lots of aluminum, and painted some canoes, so don’t take this as gospel, but:
I’d scrub it first to remove any gunk, contaminates and old flakey paint.
Once the hull is clean I would lightly sand the entire outside to scruff of the aluminum a bit for better first coat adhesion. 220 grit sandpaper should do. On small bits of aluminum I paint on a dab of vinegar to etch the metal. Vinegar is inexpensive and you may want to scrub the boat last with that. Or next to last, I’d rinse it again.
Then paint it with primer for bare metal. That primer coat will adhere better to the scuffed aluminum surface. Then, per the primer directions, top coat that with paint.
One caveat. Any paint/primer you apply will scrap off on rocks and etc. If you can live with the color choice it helps to use a primer that is the same-ish color as the paint. I expect that there are tintable primers; I’ve usually used grey or white primer and painted with the same color, so that light scratches through the paint do not contrast as badly with the primer undercoat.
One alternative there is to prime the entire hull and paint the hull bottom up to the waterline with a like color paint, and then paint from the less scrapey chines to the gunwales in the color of your choice.
