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  • Posted by Liam on June 11, 2021 at 9:00 am

    Just found our first spot of body rust. Be great full for an idiot lesson on what materials are at this junction. Is the upper smooth skin stainless or aluminum? Is this likely from the steel skeleton? Anything I can do to repair short of removing panels? It is the seam behind the kitchen.

    Thanks

    Bill replied 5 years, 2 months ago 7 Members · 10 Replies
  • 10 Replies
  • Deleted User

    Deleted User
    June 11, 2021 at 10:51 am

    Hate to disappoint you with finding some bubbles near rivets.

    Problem is contamination under the paint due to improper preparation prior to paint.

    AL

  • Dick

    Member
    June 11, 2021 at 1:24 pm

    If I had to guess it is filiform corrosion under the paint. It is common on aluminum due to poor pretreatment of something that broke the finish surface and allowed entry of moisture which “rusted” the aluminum.

    Aluminum is incredibly hard to paint or finish, such as with powder coating. It reacts quickly with air to corrode unless it has a high quality surface treatment.

  • Jon

    Member
    June 11, 2021 at 4:59 pm

    I have used a product called POR15 it will treat rust ,penetrate into metal and work intoa joint ,I was happy with results.

  • Rudy

    Member
    June 12, 2021 at 1:15 am

    We use POR 15 on our vintage airstream frames. Great stuff

  • Dick

    Member
    June 12, 2021 at 8:53 am

    Is POR15 formulated for aluminum?

  • Jon

    Member
    June 12, 2021 at 9:58 am

    Another excellent corrosion killing product is OSPHO, a dilute solution of phosphoric acid. Upon contact with corrosion, OSPHO chemically reacts and converts the oxidation to ferrous phosphate or Al phosphate, an inert salt. When it dries, the surface is treated and primed, ready for painting. There will be no more corrosion to paint over.

  • Jon

    Member
    June 13, 2021 at 10:47 am

    Thanks all. It is the original paint from 1992 but was clear coated 10 years ago. I was wondering if water is entering up at the roof line somewhere and exiting there. Going to take a look will definitely use one of those products.

  • Liam

    Member
    June 13, 2021 at 12:48 pm

    Don’t mess with just any chemicals unless you know for sure they are for aluminum. Unless you want to turn a problem into a disaster.

    Acids as Rudy suggests have an ability to eat aluminum like it was a snack. Just because it works on steel means nothing relating to aluminum.

  • Archived

    Member
    June 13, 2021 at 1:10 pm

    Thanks Jon. I have a friend who does concourse quality classic car restorations and will ask him to take a look.

  • Bill

    Member
    June 13, 2021 at 1:30 pm

    Obviously to fix it right the paint needs to be removed, the corrosion mechanically removed, either by sanding or a wire wheel, the surface to be repainted treated, and then paint reapplied.

    To be candid, to do it right it will not be cheap and unless you have more and worse situations you might just make a financial decision about the benefits of spending what it will cost to make the repairs.

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