I just finished cleaning up the gas tank from my resto-project and I was shocked at how nicely it cleaned up... turns out the tank is aluminum... who knew? I'm getting ready to paint it now, but I know that aluminum is pretty difficult to paint (generally poor adhesion, flaking, and so on). Anyone have tips or pointers that they'd be willing to share with me, so I can get the best finish possible? I'm just looking for a standard flat black finish... but I want it to hold up. Thanks, Scott
Standard white vinegar? Any particular type pf primer? ...epoxy primer? ...aluminum oxide primer? ...something else? thanks!
I've had great luck with Tempo Aviation / Zinc Phosphate epoxy based primer as a base, then any primer over that. (Downside it needs 48 hrs. curing) Their Zinc Chromate Primer was the best and had a MIL spec to boot. No longer avaliable. http://www.aircraftspruce.com/catalog/cspages/zinc.php
Clean Aluminum with Grease and Wax remover them wash down with laquer thinner and prime with Zinc Chromate primer. Epoxy flat black over that and it should be fairly tough.
I use Sherwin Williams on my window frames. Have been building aluminum windows since 2003 and never had any chipping or peeling. Sherwin Williams wash primer (P60-G2 and catalyst reducer is R7-K44). It is a phosphoric acid type etching primer and will adhere to aluminum very tightly.
Just moved to this area and I haven't found any powdercoaters around here yet... it'd be cost prohibitive to ship it off somewhere and have the work done.
I read somewhere else about a "wash primer"... I've never heard of that before. What exactly is it? ...I assume if I walk into the local automotive paint shop, they'll know what I'm talking about?
Like what ws already said, use Zinc chromate and you won't have a problem. Millions of aircraft can't be wrong.
It's no problem to spray an automotive primer (like a SEM Epoxy Primer) over this stuff, even though it's in a rattle can?
I build aluminum art work............we use this stuff, great paint! http://www.awlgrip.com/Pages/home.aspx
I have used this stuff on exposed aluminum without any cover coat for years. It has a satin black finish and lasts well. Available at most body supply stores. http://semproducts.com/Catalog.asp?prod=139
i have an old can probably from the 70s in my garage , i wonder if it's still good? google search found several sources. i see VHT has it in a spry can, SP306. O'Rielly has it on their website http://www.oreillyauto.com/site/c/search.oap?keyword=sp306
I really can't imagine anything sticking much better than etch primer. I've seen engines that were painted primed with etch primer and epoxy and painted, then later hot tanked, and the paint still survived. Not that it came out looking like fresh paint but its a pretty good testament to the adhesion properties of etch primer.
First the aluminum has to be very clean, if water beads up on it try again, i used dish washing soap and fine scotch brite till it would rinse and not break tension. while it's still wet etch it with a mild phosphuric acid solution, after a minute or so the white foam will begin to disappear , before it dries rinse well but do not touch it with your oily hands etc. Next apply alodine or PPG convertion coat (same thing) and let set for a minute or two until you see the surface start to take on a golden sheen, rinse and blow dry, then most high grade primers, epoxy, etc and zinc compounded if you can find it anymore is best. Top coat with watever you like. By the way, i painted aircraft for many years and never had one flake off. Takes a bit more time but if its worth doing then its worth doin right
Thanks for all the help... this gas tank will be a good test run. All the body panels on this thing are aluminum too.
The stuff I use is available only through Sherwin Williams commercial coatings stores, and it is not the same as the other wash primers mentioned here. The final coat resembles a coating of green vinyl and feels sort of rubbery to the touch. It will not chip or peel off.
(It's been a while since I've done a lot of aluminum painting, but back a few years go, there was a 2 part system that 3M had to prep aluminum for painting. A strong acid wash, followed by a weaker one, perhaps with an adhesion component? I don't know if they still sell it, IIRC, 225S might have been one of the components? But I'd use that, then use a plain urethane primer over it, and the tool boxes I painted seemed to last forever. Today's epoxies are probably the best, I use acid etch once in a while, but I wonder about it's effect on aluminum. It's claim to fame, I thought, was that it helped phosphate-ize steel ( highly technical talk, I know!) for corrosion protection and better adhesion. I would think that it wouldn't have the same effect on aluminum. But like I said, I have done it and had OK results.
I use moller? zinc chromate in a rattle can. Can be found just about anywhere here from the hardware shops to west marine. After coat with a rustoleum epoxy also in a rattle can. The coat comes out beautiful and strong. Strong enough to hold up to in salt water on motors and boats.