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Removing/preventing corrosion on 100-year-old tinplate roofing

I am director of a historic house museum. An enclosed porch has tinplate roofing on the floor. Until this year there has been minimal corrosion (visible rust). It has developed over the past winter in other areas of the floor, but not adjacent to walls. I am looking for information on
1) removing the rust and
2) a clear coating that may prevent rust.

Lynn Dransoff
museum director - Geneva Illinois
March 31, 2011

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The best solution is to wash the floor with a weak solution of phosphoric acid and water. The solution will remove the "rust" oxidation and protect it from future problems on that area.
As for the clear coating, there are many products; however, one must be careful if the floor will be too slippery. Polyurethane is a good candidate.

Mario Tabenig
- Huntington Beach, California
April 8, 2011

Forget phosphoric acid (it can remove tin plating too, not only rust), better try next solution: 47,5 gms citric acid [on eBay or Amazon] /47,5 gms sodium gluconate/5 gms tartaric acid [on eBay or Amazon]/1-10 lit water (according to USA patent USPT 4,264,418). After that step treat your object with 20 gm tannic acid [on eBay or Amazon]/20 gms tartaric acid [on eBay or Amazon]/1 lit water solution (try to apply it only on tin free iron spots). Clearcoat it with Paraloid B 48 N (10%) solution. Test process on some rusted tin plated scrap. Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia
April 14, 2011