TheSamba.com :: View topic - Is there any way to remove the foam that causes rust?

Wed Sep 29, 2010 9:40 am

Ok I am not familiar with these yet do forgive the question if it is dumb, but I read about foam on the panels causing rust, has anyone figured out how to remove it on the panels where it is exposed? Would coating it with waxoil help?

Wed Sep 29, 2010 9:48 am

You could burn it out with a cutting torch, then use the waxoil.

Wed Sep 29, 2010 10:11 am

What does everyone do to keep the rust under control?

Wed Sep 29, 2010 3:04 pm

Okay, what are we talking about? What foam? What (exposed) pannels? Interested because I've owned three of them (long ago rusted away---mid-west, what can I say) and am seriously considering buying another one in the near future (I know, I know-----).

chrismo

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Wed Sep 29, 2010 3:34 pm

Ok, for those who do not know, there areseveral areas of the 411's and 412's that have isocyanate or polyurethane foam injected between panels. Over the years, flexing and heat separate the foam from the metal it is stuck to. Water leaks allow the gap between the foam and panel to stay wet. This rusts the car from the inside out.

This foam is used for sound and heat insulation. It is primarily behind the double wall sections around the rear fenders,down to the body cavity area behind the sides of the rear seat and in the C pillars and surround area of the rear windshields on two and four doors....and of course....in the damn rear deck lid of two and four doors.

Urethane or isocyanate foam is impervious to most solvents. I'm not sure what this foam is. It looks and feels like isocyante. Its most probably MDI (Methylene diphenyl diisocyanate)...which was invented in 1957 and in just a few years became teh standard rigid foam insulation...and started being used in cars in the 60's

If it is isocyanate....acetone will soften it so it can be removed easier....but its still difficult. Methylene chloride will usually disolve it..as its what is used to clean the injection equipment in the plants. thats nasty stuff.

That all being said....if you can remove the bulk of it and only see surface rust starting....and can reach tehse areas easily...I would treat with muriatic acid to disolve all rust...rinse well...let it dry and flash back over with surface rust...then treat with phosphoric acid to rust proof it. Then spray in any primer and it will be as good as you can get.

Ray

Wed Sep 29, 2010 6:16 pm

Quote: That all being said....if you can remove the bulk of it and only see surface rust starting....and can reach tehse areas easily...I would treat with muriatic acid to disolve all rust...rinse well...let it dry and flash back over with surface rust...then treat with phosphoric acid to rust proof it.

Are these areas easy to reach?

Thu Sep 30, 2010 12:52 pm

Not really. Most are pretty well sealed up and are not the big issue. its the foam in areas of the rocker panels that got water in around the chrome trim clips...and also around the rear windshield where there were several sheet metal screws that the factory drilled through into the body to install that damn carboard trim/air duct piece under the rear windshield...that cause problems.

If you have the rear fenders off, the rear seat completely out and the liner/carboard out of the engine comparment....you can reach alot of them with rods and picks. Ray