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Painting New and Bare Aluminum

Discussion in 'The Hokey Ass Message Board' started by Beep, Aug 14, 2006.

  1. :mad: Seems to me, if my memory serves me, and I'm not sure it does that very well anymore, paint doesn't stick to aluminum very well. :rolleyes: What is the best way to prep aluminum and what primer to use so a good paint will stick and stay? Would appreciate any help. Thanks
     
  2. belle
    Joined: Jul 30, 2006
    Posts: 149

    belle
    Member

    back when i messed with a few airplanes , we used zinc chromate primer on the aluminum first , then used normal paint materials over it
     
  3. porknbeaner
    Joined: Sep 12, 2003
    Posts: 25,834

    porknbeaner
    Member

    That's what i was going to say.
    Zinc chromate is the only way to get paint to stick to it. Clean it good with some White vinigar first then a good even coat of zinc chromate and then paint it to your hearts content.

    you can buy it in most paint supply houses in a rattle can.
     
  4. We paint aluminum every day, thing is I don't do it my self so I'm not sure of the correct names but I will check tuesday........................I know the final paint is AWLGRIP.
     
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  5. Degrease and remove all residue from the aluminum .Dont use any steel bristle brushes or iron oxide sandpapers. Clean with an aluminum cleaner /conversion coating (Sherwin Williams W4K263 or equivalent). Do not omit this step even if your using a self etching primer. Apply an epoxy zinc chromate primer (Sherwin Williams GBP 9870/981)to the bare aluminum per mfg instructions. Apply primer surfacer after proper flash time. Cleaning with vinegar and water will work if conversion coating isnt available but shouldnt it be reduced 1part vinegar 3parts water. I have heard of doing it this way but never tried it myself. The funny part of all this is that you only need 2 mils of the zinc primer to be effective . You can actually see the aluminum thru some brands of primer.

    Larry
     
  6. Thanks for all the information. So, what I get from all the above is 1) don't sand the aluminum, but clean it thoroughly. 2) Apply a good zinc chromate primer. 3) apply primer surfacer. 4) then paint with AWLGRIP type paint. One more question,,,what is a primer surfacer and what does it do? Again, thanks to all.
     
  7. cabriolethiboy
    Joined: Jun 16, 2002
    Posts: 777

    cabriolethiboy
    Member

    I know the paint guy will dissagree with me, but I have been making aluminum hoods for over 25 years and have been running them on my cars since 1977. I have had more trouble with the zinc chromate primer than I have had not using it. What I do is DA or sand the hood all over ( every square inch ), clean it with laquer thinner, and then treat it like I was painting steel. My sedan delivery hood was painted 20 years ago and it still looks good. I think the secret in any situation is to get it CLEAN.[​IMG]
    Pic thanks to carnut.com.
     
  8. McKee
    Joined: Jul 22, 2005
    Posts: 2,200

    McKee
    Member

    Definetly sand the bare aluminum to give it a "tooth" for your primer to mechanically bond to. I've used Glasurit products a lot and they have an epoxy primer specifically for aluminum that works great. I've painted a number of aluminum bodied cars with good results.
    Any good paint jobber will have procedure sheets on their products, follow them to the tee and you shouldn't have any problems.
     
  9. Getting close. You should always chemically clean aluminum with a conversion/cleaner . I dont intend to be disagreeable.I can only state what I have been taught and what I have seen work over the years in the business.
    Proper metal cleaning is critical to long term paint film life on any metal ,steel, aluminum or ....The use of zinc chromate is one of the most important refinishing steps and should never be omitted. The adhesion and rust inhibiting qualities of this material are unparralleled. Leaving zinc primer unused for extended periods of time can create some useage issues,mainly settling of the zinc in the resin. If unmixed this will result in primer that doesnt dry and feels sticky even days later. Keeping the primer agitated daily ,will eliminate this problem. I have seen some aluminum panels painted without zinc and there can be times when this has been successful. With the addition of so many aluminum panels on todays cars we find that the cleaning and zinc priming processes hold up so much better to the elements and extremes that many autos are subjected to.

    I believe that AWLGRIP is a paint company product name for zinc chromate.
    Check with CTfuzz to confirm.

    Primer surfacers are designed as a sandable filling agent for small imperfections and sand scratches. Most primer surfacers do not have any rust inhibiting qualities. Make sure to use a quality sealer before topcoating the primer surfacer. The surfacers are pourous and sealing is essential for proper topcoat gloss retention and fade resistance.

    If you have questions regarding painting , products and proper application . Google the paint mfgs web site. All have this info posted.
    Some even have on-line technical support if you need help with any problems.
    Precise mixing of these products in the correct ratios is very important with todays products. You shouldn't bartend the mixing of the paints as this can sometimes make for lots of fun.
    One other important part of refinishing is to only used one mfg's product materials from start to finish . Intermixing brands can create problems because these materials are designed to crosslink between one another.

    Larry
     

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