> >DO NOT use silicone rubber anywhere around copper - it produces  acetic
> >acid fumes which corrodes copper even if they are not touching.  Lots of
> >people make this mistake.

> Isn't this true only of the stuff you buy at the local hardware store? It
> is possible to purchase non-corrosive varieties of RTV intended for
> electronic purposes. Dow-Corning 748, for example, is a non-corrosive
> RTV type sealant. GE makes similar products.
> Sometimes these are sold as "aviation" or "aerospace" sealants, in
> addition to an "electronic sealant" name.

> Correct, there are brands of silicone rubber that are made for
> electronics, and your local hardware store won't have any of them.

Faraway here in NZ you can buy "neutral cure" silicon rubbers intended for
eg marine use. These are sold in the local (very large) hardware store and
in the local auto supply stores. (I use neutral cure "Silastic Marine" for
all my silicon rubber applications - that brand may not feature where you
live).

The magic term here is "neutral cure". If you take a nice big breath of the
air near uncured sealant and can't smell any acetic acid you probably have
the right stuff. (if you don't know what acetic acid smells like take a nice
big breath of the air near the wrong stuff :-). Its quite tangy and
distinctive. Vinegar is dilute acetic acid so if you know what vinegar
smells like ... .



        Russell McMahon

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