[Elecraft] Removing Varnish from Toroids

[Ron D' Eau Claire]

>...The enamel is hard to remove....
>  WB3KDB  K1 # 1075.

It is possible that they have changed vendors since my K2 was built nearly
two years ago, but I found the enamel very easy to remove without using the
soldering iron. I simply pulled the end of the wire over a moderately sharp
corner  - a very dull knife blade. The enamel tended to pop loose in long
sheath, almost like other types of insulation, and slide off of the wire
leaving a clean copper surface ready for tinning.

Some types of enamel (especially the stuff made for high-temperature
applications like transformers and motors) can be really tough, no matter
how it is done. Fortunately I did NOT find that to be true of the wire
Elecraft supplied me in my kit.

I've done it both ways: blob and strip. Whether or not I use the "blob"
method depends upon whether I have my large, hot iron handy and how 'clean'
I want the finished wire to look. The blob method necessarily leaves a
scorched ring of enamel at the end of the tinned wire. but otherwise works
very well with enough heat applied.

I was amazed at how easy it was to simply 'strip' the enamel from the
Elecrraft-supplied wire and did mine that way.

IF one 'strips' the enamel, the same cravat applies that one must consider
with stripping any wire. That is this. If you "nick" the wire on the sharp
edge - leaving even a tiny little 'dent' in the wire, it WILL eventually
fail there. Because the 'nick' is a slightly weaker spot, any bending
movement will be concentrated on that one spot instead of being distributed
along the length of the wire - leading to crystallization and a failure of
the wire at that point. How soon depends entirely how much motion the wire
is subjected to and how deep the nick is. It might happen next week, or your
great, great, grandchildren might wonder why the antique radio suddenly
stopped working just because they moved to a new place.

Ron AC7AC
K2 # 1289