RE: NST brands

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Steve Conner" <steve.conner@xxxxxxxxxxx>

>Does anyone know of any NST brands that do not use
>asphault or tar to pot their NST's in.
>Thanks in advance :-)

Hey Bobby,

I think some of the newer NST makes (including the one you're trying to fix)
use some sort of epoxy (or maybe urea formaldehyde) resin mixed with a
grainy filler that could be sand. It sets like rock and is almost impossible
to get off. The cooking process doesn't seem to work either- the resin just
decomposes and stinks instead of melting properly.

I had a Tunewell NST like this (Tunewell is a British make) that I burnt out
by running with a too-large static gap. One of the legs shorted to ground
internally.

The potting was the same caramel coloured material that you mentioned a
while back. After a bit of "investigation" with chisels and sledge hammers
it turned out to be this mixture that I'm guessing is epoxy and sand. It was
impossible to get off and my attempts ended up destroying the transformer
completely.


Steve C.