Re: That brown glue stuff


"N_Cook" <diverse@xxxxxxxxx> wrote in message
news:g5d0pk$7he$1@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Used for fixing otherwise floppy bits to boards.
Is it hygroscopic ? whatever the word is, but pulls dampness out of the
air.
Beocenter 4000 from 1985 with the LC7815 (not V reg) electronic 2 pole 4
way
switch, internally locked into Aux only input, so disabling everything
else.
0.7 inch pitch 28 pin DIP but now removed and replacement available.
Affected input was on one side of the IC and some of this shitty brown
stuff
on the other. But now removed , the 2 glued pins are almost corroded
through
but not obvious before removing the IC, and have presumably conducted
moisture, capillary fashion, into the IC.
So will remove that glue and another dollop near another IC. Will hot-melt
glue go the same way after a qurter of a centuary.
Is it bulking filler in these glues that cause the problems ? I have used
talcum powder to bulk out on occassions but could that be problematic in
future , so a better choice?

The brown glue that usually causes the problems you describe normally
becomes very brittle and chips off easily.

If something really does need tacking down I'd use a very small spot of
superglue or a blob of 2-part epoxy, for larger components that need support
but need to flex with thermal expansion silicone RTV is a good choice,
instant gasket is sometimes cheaper from auto accessories stores, or if you
use a lot of it a tube of RTV for a "mastic gun" from a builders yard
usually works out cheapest.


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