From: Michael Coslo on Thurs, May 29 2008 6:02 am:
AF6AY wrote:
From: (Dave Platt) wrote on Mon, May 26 2008:
In article ,
W3CQH wrote:
I wonder if items such as Strip-X became obsolete due to changes in
insulation composition, i.e. not working on new types of insulation. But
I do agree about the folk who would protect us from ourselves. Strip-X
was pretty innocuous stuff.
As far as I could tell from communications with General Cement,
it was FEDERAL REGULATIONS that was the issue. GC already had
over a hundred products in its catalog so they weren't going to
suffer any real loss in income. They've been making 'radio'
chemical products for over 75 years.
Did you by any chance try some old style enameled wire in your
experiment above?
"Experiment?" The only experimentation I did was well AFTER
my last bottle of Strip-X was used up, residue dried out. Strip-X
from GC worked for me the first time I tried it long, long ago.
That experimentation I wrote about was to find a possible
substitute for GC Strip-X.
GC Strip-X has worked on enamel-coated magnet wire, PolythermalEze
(a trade name), different kinds of wire-wrap wire. It didn't work
on the surplus Teflon-coated #25 AWG magnet wire I got surplus
from a transformer maker (#25 is an odd gauge, heh heh, but the
transformer makers use practically every gauge in the AWG table).
Tetrafluouroethylene is pretty inert stuff so few chemicals will
affect it. Teflon also abrades easily compared to other
insulations so it is relatively easy to strip with a knife.
The acetone issue is a strange one. Acetone is one of the safer
solvents out there, heck our body even produces some acetone.
I think that should be 'acetyls' in the human body, not
acetone per se. shrug
Acetone won't strip off enamels or other polymers used on
magnet wire. I tried that, too, also toluene.
Acetone as a solvent was dropped from the model hobby industry
chemicals once gas-powered models started using "hot fuel," the
methanol-based stuff for glow plug engines that took over from
real spark plug ignition model gas engines in the late 1940s.
Methanol softened acetate-based paints, whereas the 'ordinary'
gasoline used in spark ignition engine fuel did not affect
acetone-solvent lacquer commonly called "dope" in model hobby
industry jargon. For years Testor Chemical Company, also in
Rockford, IL, had lacquer paint bottle labels of DOPE in all-
capitals, something you just CANNOT DO in today's restrictive
society. Building model airplanes was fun, the "dope" smelled
very nice, so the blue-noses made all kinds of bad noises
about the "evils" of having fun in a hobby. Sigh.
Digression: The first small two-cycle gasoline engines used
real spark plugs of very small size. I still have two
Champion brand spark plugs in a storage area...less than a
half-inch long...and those are for the big class C and D
engine displacements. I learned to solder wires properly
by making the spark ignition packages for gas-powered
models. The "spark coil" for those was a tiny one that was
picked up by the first electronic flash units for camera use
in the 1950s...ideal for igniting the Xenon flash tubes that
replaced the one-shot photoflash bulbs.
Yes, I was emitting "spark" RF in the late 1940s with those
spark-ignition engines, all without being licensed to do so.
So were other gas-engine modelers and just about EVERY
running automobile of that time! :-)
My late father-in-law was a polymer chemist. He died in 1977
so can't help me. I just hope that some chemist could come to
the aid of us hobbyists using coated magnet wire and provide
us with a GOOD product like Strip-X was. Meanwhile, it's back
to being VERY careful with a sharp X-Acto knofe and scraping
coatings. With #34 AWG that requires Zen-like calmness...
That is an understatement1 8^) I have to make sure I am in a good mood,
and no coffee for me that day before I attempt that sort of thing.
Coffee calms me down. Always has. Makes for good moods. :-)
Actually, I use a fine emery finishing paper to strip fine
gauges of enamel-coated wire. I've used X-Acto hobby knives
for the heavier gauges. Emery paper (easy to get at do-it-
yourself stores) allows a gentle stroking of a folded emery
paper over the wire. I find it works better to draw the
emery paper over the wire rather than pulling the wire through
the paper. Less nicking than with a knife blade for #28 to
#34. I just finished a few small toroid inductors using #34
enamel-covered last week. Not recommended for beginners. :-)
PATIENCE (in all-caps) is needed to make toroids of the T37
size (about 3/8" OD), drawing a very-carefully-folded wire
bundle through the center hole in a toroid core. :-) THAT is
the "Zen" thing. Good self-control is absolutely necessary,
can't use slap-dash hurry-up behavior.
By the way, don't use "Q-Dope" for coating finished inductors,
any type. Despite what the ads say, it does NOT enhance the
coil's Q. Trials of before-after measurements on a Q-Meter
haven't shown goodness. ALL coatings degrade inductor Q.
I've found that oil-based 'maritime' clear varnish to result
in less degredation of Q than other coatings. I've used
McCloskey "Gym-Seal" brand with good success on making
inductor coatings that adhere to windings for years. It is
available nationally in do-it-yourself stores.
Q-Dope (originally acetate-solvent based, now probably using
toluene solvent) will "lift" from smooth surfaces within a
year in climates with only moderate humidity. Q-Dope only
adheres well to all-polymer-based surfaces, won't get into
fine pores. 'Maritime' varnishes NOT polyurethane based DO
grab porous surfaces. I've tried various polyurethane-
based varnishes with mixed results; the makers of those
apparently have a rather large variation of ingredients.
Varnishes take 2, 3 days to properly cure if used on coils.
That's the down-side of using the stuff in hobby applications.
However, on a Q-Meter the characteristics of 'maritime'
varnish coated inductors don't change much after it has
reached a tacky state, roughly 12 hours after application.
It ain't for 'weekender' projects started on a Saturday and
'finished' on Sunday.
73, Len AF6AY