Marty wrote:
Marc Heusser wrote:
In article , hpeer
wrote:

Yeah, I think the foam works better than the bed liner. The foam
is a urethane and so is much of the marine paint.

Be careful - urethane may be acidic, and iron rusts in acids. In a
basic environment it is stable such as in cement/concrete.

Say what? Best rethink that thought:
http://depts.washington.edu/matseed/...0Corrosion.htm

Sorry but that link actually supports the original argument.
From the link:

When considering the initial state of the reinforcement in our
concrete bridges, we can state that the cement acts to protect the
reinforcement by passivating it. It forms a protective oxide coating
on the steel giving a pH of 13-14 adjacent to the steel. The
corrosion of the steel reinforcement occurs below pH 11. The pH of
seawater is about 8.


Yep, confirmed, stable in a sufficiently basic environment.
Of course, if you have voids or cracks next to the steel, eventually
chloride ions will get in there, the PH will drop, the reinforcement
rust and the structure will fail, but that's not a problem with steel in
a basic environment, its a problem maintaining a basic environment.

For a counter-example, examine *any* unprotected steel object exposed to
acid fumes or acid contact. Even the top of an old ketchup bottle . . .


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Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
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