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Depotting a resin-filled tranny
Original poster: "sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sundog-at-timeship-dot-net>
I got an interesting delimma. I have a 15/30 and a 12/30 that I want to
depot. The 15/30 is a tar-potted jobber, the 12/30 is a resin-epoxy filled
block. The 15/30 is no problem, a few days in the freezer, short the leads
and let it run for 1/2 an hour or so, and then gentle use of the air chisel
will pop it out of it's tar block. Keyword is "gentle", with a cutting
chisel on the air hammer, not the pointy one, and patience. Knowledge of
what is where in the NST case helps too.
But the epoxy resin one...I haven't tried to depot one yet, and despise
soaking them. The 9/60 took 2 weeks, remained gooey and nasty. I'd rather
get as much tar off as I can chipping, then use a pick on the rest and when
re-potting it in a metal container (ammo cannister prob'ly), put it in it's
bath of oil or vaseline, and let it simmer!!! Until little blobs of molten
tar appear. That way I get the potting in where the tar can melt out of.
So far experimental chipping on the epoxy blocks were not too good. it
seemed it wouldn't release the windings without trying to take them off
Soaking the epoxy is out. Maybe apply heat with a heatgun and airchisel?
The epoxy trannies I had that died all shorted to the case by tracking from
the screw in the HV bushings. The bushings usually cracked when this
happenend, and the shorts became almost impossible to fix (tried to dremel
out the charred epoxy, no luck.) I would rather depot the tranny now than
have to have it fail on me later when I'm tinkering on a coil (and spoiling
an evening of coilin').
Ideas? (throwing it off the 6 story building I work in isn't an option,