another rust question

fourspeed · January 14, 2009 at 5:26 AM

I have a spare driver's side door that has a little surface rust, mostly on the interior side, and some rust bleeeding around the seams where the outer skin is folded around the door. The rust issues come from the door being stored in a barn lean-to with one side open to the elements. From a quick observation, this is all surface rust, no rust through issues are apparent, but I am concerned with what cannot be seen. I had thought about having the door commercially chemically stripped, but am concerned about chemical leaching in and around the seams. What is the preferred method of treatment in this situation? I would appreciate the advice of restorers who have had to deal with this situation. Thanks.

65Rangoon_old · January 14, 2009 at 10:30 AM

What I've done in the past is applied phosphoric acid to those surface rust areas. It does a good job removing light rust. Keep it wet however until your happy with the result. Once done, you can either let it dry, or clear water rinse it away.

Letting it dry leaves a crust (paintable but ugly) so I've always done the rinse, followed by force air drying the cleaned areas, followed by Rust-Oleum red oxide primer for rusty metal. My technique with the primer has been to pour it inside the door then rotate the door 360 degrees to allow the primer to migrate into all the door pinch weld areas. I also brush primer on to the exterior portions of the pinch welds, the idea being to let it ooze into the pinch welds to maximize penetration, then wipe off the excess.

It's a PITA procedure but I think a very effective. I would also recommend thinning the primer to get the best flow into those tight areas.

Heavily rusted areas can be treated with muriatic acid followed by the water rinse, force drying, and finally the phosphoric acid treatment descibed above. Muriatic acid is toxic to say the least, so ventilation and a huge amount of caution in its handling are a must!

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SixT5HiPo · January 17, 2009 at 12:36 AM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

Muriatic acid is toxic to say the least, so ventilation and a huge amount of caution in its handling are a must!

That's for sure. To prevent serious harm, a proper respirator mask must be used with filters designed to neutralize the deadly gas given off by muriatic acid so it can't get into the lungs. Chemical resistant gloves would also be strongly advised before handling such a strong acid.

C6ZZKGT · January 17, 2009 at 12:58 AM Official Post

Sounds like the same acid that the mob uses to dispose of bodies.<img src=images/icon_smile.gif border=0 align=middle>

-Fred-

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