Metal finishing Q&As since 1989

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Rusting nails

2003

Hi,

We have done a test in science at ponsinbey into with rusting nails. We have done 2 test are first nail was half submerged in water the other side was in open air the end that was in the water rusted and left a brown substance that fall off when we picked up LIGHTLY. Our second test was one nail poked through a jar lid half way through the very tip underwater rusted then left a gap and then rusted again and left a gap where the water line and then the mettle jar lid rusted and the nail in the air but under jar lid.

Why did nail not rust on water line or in middle of water and what is brown substance that is slimy and easy to fall off.

Leighton H
- Aukland, NZ

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2003

The brown slimey stuff was the object of the experiment: it's rust.

Your second description is a little harder to follow, but it sounds like the tip of the nail rusted because it was in the water; and the contact point where the rust met the lid rusted because of galvanic action.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey