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painting aluminum

Discussion in 'The Hokey Ass Message Board' started by punter, Apr 13, 2011.

  1. punter
    Joined: Oct 26, 2010
    Posts: 20

    punter
    Member
    from Arizona

    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
     
  2. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don
    Member

    First, wash with wax and grease remover. Then do it again. Rinse with vinegar, prime.
     
  3. punter
    Joined: Oct 26, 2010
    Posts: 20

    punter
    Member
    from Arizona

    Standard white vinegar?

    Any particular type pf primer? ...epoxy primer? ...aluminum oxide primer? ...something else?

    thanks!
     
  4. Bearing Burner
    Joined: Mar 2, 2009
    Posts: 917

    Bearing Burner
    Member
    from W. MA

    Self etching primer followed by regular primer.
     

  5. Ob1
    Joined: Jan 21, 2010
    Posts: 411

    Ob1
    Member

  6. ETwagon
    Joined: Apr 6, 2007
    Posts: 97

    ETwagon
    Member
    from Arizona

    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
     
  7. aaggie
    Joined: Nov 21, 2009
    Posts: 2,531

    aaggie
    ALLIANCE MEMBER

    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.
     
  8. oldspert
    Joined: Sep 10, 2006
    Posts: 1,259

    oldspert
    Member
    from Texas

    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.
     
  9. ibarodder
    Joined: Oct 25, 2004
    Posts: 223

    ibarodder
    Member

    Could you get it powder coated?
     
  10. punter
    Joined: Oct 26, 2010
    Posts: 20

    punter
    Member
    from Arizona

    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.
     
  11. punter
    Joined: Oct 26, 2010
    Posts: 20

    punter
    Member
    from Arizona

    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?
     
  12. lowelife
    Joined: Aug 30, 2007
    Posts: 400

    lowelife
    Member

    Like what ws already said, use Zinc chromate and you won't have a problem. Millions of aircraft can't be wrong.
     
  13. punter
    Joined: Oct 26, 2010
    Posts: 20

    punter
    Member
    from Arizona

    ET Wagon was saying that it is no longer available... can it still be found?
     
  14. punter
    Joined: Oct 26, 2010
    Posts: 20

    punter
    Member
    from Arizona

    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?
     
  15. KrisKustomPaint
    Joined: Apr 20, 2007
    Posts: 1,107

    KrisKustomPaint
    Member


    Wash primer, Acid etch primer, Etching primer, different names for the same thing.
     
  16. 51 MERC-CT
    Joined: Apr 5, 2005
    Posts: 1,594

    51 MERC-CT
    Member

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  17. need louvers ?
    Joined: Nov 20, 2008
    Posts: 12,906

    need louvers ?
    Member

    Hey punter!
    What part of AZ. are you in? Might be able to give help on services locally. P.M. me.
     
  18. 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
     
  19. KrisKustomPaint
    Joined: Apr 20, 2007
    Posts: 1,107

    KrisKustomPaint
    Member

    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.
     
  20. fleetbob50
    Joined: May 1, 2006
    Posts: 306

    fleetbob50
    Member
    from Waco,Texas

    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
     
  21. punter
    Joined: Oct 26, 2010
    Posts: 20

    punter
    Member
    from Arizona

    Pretty close to you actually... I'm just outside of Tucson
     
  22. punter
    Joined: Oct 26, 2010
    Posts: 20

    punter
    Member
    from Arizona

    Thanks for all the help... this gas tank will be a good test run. All the body panels on this thing are aluminum too.
     
  23. hotrod40coupe
    Joined: Apr 8, 2007
    Posts: 2,562

    hotrod40coupe
    Member

  24. oldspert
    Joined: Sep 10, 2006
    Posts: 1,259

    oldspert
    Member
    from Texas

    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.
     
  25. chopolds
    Joined: Oct 22, 2001
    Posts: 5,933

    chopolds
    Member
    from howell, nj
    1. Kustom Painters

    (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.
     
  26. 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.
     

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