painting aluminum

[izzybird]

Due to my "dark ages" internet connection searching forums is a week long task, so I'm gonna take the easy way out and just ask. I've read alot of differing opinions on painting aluminum, some extremely involved and others claiming automotive primer and paint are acceptable. (I know the latter is not correct) I would like to restore my old aluminum lonestar. The paint was taken down with jasco stripper by an uncle years ago. He didn't exactly get ALL the paint off, but pretty darn close. Could someone give me the lowdown on properly painting this boat? I have a good gun, large compressor, and a well stocked airtight shop. I don't need this thing to be perfect, but I do want to use the right process. Thanks to all in advance.

 

[tashasdaddy]

Re: painting aluminum

i have had great results with Rustoleum, they even now have marine paint.

 

[Moody Blue]

Re: painting aluminum

The aircraft industry uses a primer called zinc chromate conversion primer. Its a yellow/green color. Can be hard to find in most hardware stores.

Offers great adhesion for the top coat and provides corrosion protection as well.

 

[5150abf]

Re: painting aluminum

Moody Blue hit it, you can paint the aluminum with anything you want but you have to use an"acid etch" primer first.

Paint won't stick to aluminum and this primer actually ecthes into it to get a good hold.

 

[AZMinyard]

Re: painting aluminum

Welcome to iboats. I was able to paint my aluminum boat thanks to the help and advice from the good folks here at the forum. You will find all your questions answered, just be sure to ask the right ones!

Believe it or not, I was able to find the self etching primer at WalMart. It was in the automotive section, not the paint section.

A couple high level steps:
1. Power wash the boat to remove all debris. If you do not have a power washer, either rent one or go to a coin-op car wash.
2. Sanding is always highly recommended. If it has been years since it was last sanded, you are likely to have some oxidation.
3. Sanding or not, wash the boat with a 50/50 mixture of vinegar and water. If you have a power washer with an intake tube, this works well. Wash and scrub with an abrasive sponge. This removes oxidation, be sure to rinse well.
4. You might as well use Gluvit at this point in time if you are painting the inside of the boat as well, especially if it is a riveted boat.
5. Prime with the self etching primer. Follow the coats as instructed on the can.
6. Paint. If you have a small boat, spray cans are fine. If not, I would recommend the Rustoleum in a bucket through your sprayer. As TD stated above, they now have marine paint for metal surfaces.

You might also consider some form of flooring. General consensus here appears to be that carpet is a pain to maintain and holds fish guts, the spray type do-it-yourself bed liner is a bit disappointing, the roll or brush type do-it-yourself bed liner works well and that a viable and cheap alternative is to sprinkle sand on the first coat of floor paint while it is still wet and cover well with 1-2 more coats for a non-skid surface.

Good luck, take some before and after pictures and post in the boat restoration forum!

If you are interested, the link to what I did is:
http://forums.iboats.com/showthread.php?t=273399

 

[izzybird]

Re: painting aluminum

thanks everyone. I'm still trying to remove the last bits of remaining paint, but almost got it. A little 14' boat isn't so little when doing this kind of work! I'll try to put up some before and afters and also state whether or not I got good adhesion.

 

[CATransplant]

Re: painting aluminum

The other option is to leave it alone. An unpainted aluminum boat will never have peeling paint or need to be repainted. If you get all the paint off of it, you'll have a silver-colored aluminum boat.

That's what I did with my little 12' boat. I got about 99% of the old paint off the outside of the thing and called it good. It doesn't seem to scare the fish, and requires zero maintenance to the finish.

 

[reelfishin]

Re: painting aluminum

The other option is to leave it alone. An unpainted aluminum boat will never have peeling paint or need to be repainted. If you get all the paint off of it, you'll have a silver-colored aluminum boat.

That's what I did with my little 12' boat. I got about 99% of the old paint off the outside of the thing and called it good. It doesn't seem to scare the fish, and requires zero maintenance to the finish.

That works too but if he runs in saltwater, that might not be a good idea. Salt gets in every nook and cranny, it gets behind every seam and rivet it can and just corrodes the aluminum over time. The best bet is to seal every seam and river on the inside with Gluvit, sand and prime the outside with a self etching primer, then to paint it generously with several good coats of paint. Make sure that any salt or existing corrosion is removed before painting.

One problem area on most aluminum boats is the keel, many have a riveted keel that can hold salt deposits and corrode the aluminum where you can't see it. I've run across several that were damaged this way. Its about impossible to get into that area other than removing the keel and all the rivets. The right fix is to keep this area sealed and free of saltwater.
I took a few apart and found that the thinner hull aluminum had all but corroded away above the keel itself from either residual salt that laid in there over the years or from saltwater in the bilge.

 

[CATransplant]

Re: painting aluminum

True. I lost an old alumicraft after using it once in salt water then not using it for another couple of years. The keel area just rotted away.

A lot depends on the alloy used in building the boat. Some aluminum boats are made of an allow that doesn't resist corrosion from salt. I do not know how to identify them, frankly. Others are pretty good about the corrosion.