[time-nuts] KS-24361 Power Module Repair

Chuck Harris cfharris at erols.com
Tue Apr 14 08:50:26 EDT 2015


I thought the context did a pretty good job of explaining it,
but if it did not, I am sorry.

Epoxy potting compound is a lot easier to remove than the silicone
RTV based varieties... Although the silicone variety starts out
soft, it is not crumbly.  The epoxy sort loses its cohesiveness
with its hardness when hot.  If you stick a screwdriver into it,
and twist, it pops off decent sized crumbs.

What I typically do is take a dental probe that is dull, and slide
it between the board and the potting compound, and strip off chunks
of the potting material.  Or I use small 1/8 inch blade screwdriver
and do the same.  It goes pretty fast... you avoid toroids, and
things with fine wires, of course.

The easiest way to remove silicone potting compounds is to take
advantage of silicone rubber's voracious appetite for slurping
up petroleum solvents.  Put the item you want to strip in a
container filled with naptha (aka lighter fluid, or fuel) and let
it soak over night.  By morning, there will be this highly bloated
and fractured gelatinous mess all over the board.

-Chuck Harris

Bob Stewart wrote:
> OK, that explains your comment.  This is most likely a silicone based potting
> compound.  It's a bit softer than an eraser when cold.  Very little of it was
> actually stuck to the board or components.  If it had been a hard, epoxy-based
> covering, I wouldn't have bothered with it.
>
> Bob



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