September 1965 Electronics World
Wax nostalgic about and learn from the history of early electronics. See articles
Electronics World, published May 1959
- December 1971. All copyrights hereby acknowledged.
Liquid Wrench, of which I
have a can sitting in my garage, has been around
since 1941 per the company
website. WD−40, of which I also have a
can, first appeared in
1958. That is surprising to me since
I was using WD−40 long before having heard of Liquid Wrench. Mac introduces
side-kick technician Barney to Liquid Wrench in this episode entitled,
"Chemicals for the Service Shop." It appeared in the September 1965 issue of
Electronics World magazine when both products had been widely available for
quite a while. Strange that WD−40 was not mentioned, too. Also discussed in the
technodrama are liquid protective coatings like spray-on insulation and
electrical connection weatherproofing coatings, cleaners (as replacements for
the dreaded carbon
tetrachloride, aka "carbon tet"), adhesives, lubricants, and some products
like component cooling sprays and paints/stains for repairing cabinets.
Mac's Service Shop: Chemicals for the Service Shop
The wide variety of liquid service aids
available today are as valuable to the technicians as conventional tools.
Barney marched into the service department and ostentatiously placed a small
spouted metal can on the shelf holding the various chemical service aids used in
radio and TV servicing. "Please note," he said to Mac, his employer, "my free-will
offering of one can of Liquid Wrench."
"What's Liquid Wrench and why the sudden burst of generosity?"
"You might say Liquid. Wrench is a second-generation penetrating oil. I discovered
what it could do Sunday when I took down my ham transmitting antenna to replace
the feed-line. Bolts holding the wire in the terminals were so badly rusted and
corroded I couldn't budge them. The friend helping me suggested penetrating oil,
but I didn't think much of the idea. My limited experience with penetrating oil
led me to believe you had to let it soak in for two or three hours before it did
much good; and I needed that antenna back up right away to keep a schedule. But
my friend got his can of Liquid Wrench and squirted it on the bolts and nuts. In
two or three minutes we were able to unscrew the nuts. I don't mean we could turn
them with our fingers, but they all came off with a little persuading.
"Right then I decided I wanted a can of this quick-acting penetrating oil in
my hip pocket the next time I climb a tower to replace an old TV feedline or to
loosen the rust-encrusted nuts of an antenna rotor. By golly, there's progress in
everything these days - even in penetrating oil!"
"It's odd you should discover this right now," Mac said. "I decided the same
thing a couple of weeks ago and filled out an order to update our 'liquid tools,'
as you might call them. I was arranging these on the shelf just before you came
in, but a modern penetrating oil is one thing I overlooked.
"A technician is prone to think only of hand tools and service instruments as
service aids and forget all about the wide variety of chemicals that can make his
work so much easier. The day when all the chemicals a service shop used were a tube
of speaker cement and a bottle of carbon tetrachloride is long gone. What say I
sort of go through the items on this shelf with a little refresher discussion of
the uses - and abuses - of each?"
"To coin a phrase, 'You're the boss,''' Barney quipped as he perched himself
comfortably on a stool and prepared to listen.
"Let's start in the 'Protective Coatings' section with this bottle of liquid
tape. In modern compact radios, tuners, tape recorders, and TV sets, wrapping an
exposed wire with tape to provide insulation is often as difficult as trying to
splint the leg of a mosquito inside a safety match box. Instead, you simply brush
on a coating of the contents of this bottle. It quickly dries into a crack-proof,
high-voltage layer of insulation. You can also brush it on the handles of tools
to insulate them. This bottle of red insulating varnish will do the same job for
solder connections, and it also serves nicely for sealing adjusting screws. Of course,
we can call on our old reliable corona dope for really tough arcing cases in the
high-voltage circuit. Finally, here is a bottle of silicone resin coating with the
trade name of Print Kate to restore the protective coating to printed circuits after
a circuit repair has been made."
"That darned coating is a big fat nuisance when you're trying to solder a break
in a printed circuit," Barney offered.
"Not if you use this Print Kate Solvent especially designed to remove the silicone
resin," Mac said, moving over to the next section he had designated "Solvents" with
the shop label-maker. "And incidentally, here is some special low-melting-point
solder especially designed to resolder a break in a printed circuit without the
necessity for too much damaging heat. Your Liquid Wrench goes in this section as
does this bottle of acetone for dissolving speaker cement. Always remember, a little
of this goes a long way."
"Yeah, I know," Barney answered. "The idea with acetone is to apply a little
sparingly to a speaker-cone dust cover and then wait a few seconds for it to soak
in. After that the cover can be lifted off intact with tweezers and can be used
again. Trying to hurry things up by dousing the center of the cone with acetone
is a good way to separate the voice coil from the cone."
"Right," Mac approved, "and the same thing goes when realigning a warped voice
coil. After the speaker shims are in place, the idea is to apply just enough acetone
with a long curved eyedropper to the pleated voice-coil spider to soften it and
allow it to take a new set with the voice coil properly aligned. Too much acetone
may loosen the spider from its plate or, still worse, may carry softened cement
down into the space between the voice coil and the pole piece. If this occurs, you've
"Hey, I'm surprised, knowing how you feel about the stuff, to see a bottle of
carbon tet on the shelf under 'Cleaners.' "
"Well, I still consider it deadly dangerous and know that breathing the fumes
can produce serious liver damage; but I'm also a great one for 'going by the book,'
and the fact remains that several tape-recorder manufacturers still specify carbon
tet for cleaning tape heads, capstans, and even pressure rollers. Others warn against
using the stuff on tape heads or any rubber parts. I suppose it depends on the material
in which tape-head laminations are embedded and the chemical nature of the rubber
used. At any rate, here is a bottle of tape-head cleaner for general cleaning of
that area, a bottle of alcohol for use where it is specified, and this carbon tet
to be used when called for. But when you use this last be sure you have plenty of
ventilation so you don't breathe the fumes, and be careful not to splash any into
your eyes or into any breaks in the skin."
"Don't worry. I'm just as scared of that stuff as you are. I see you have a new
pressure can of contact cleaner and another of glass-and-plastic cleaner. You know,
it amuses me to see an inexperienced technician hopefully squirting contact cleaner
on the outside of a volume-control shaft. In a very few cases this may clear up
the trouble for a few days, but for lasting improvement the cleaner must reach the
sliding contacts inside the control. I use the auxiliary flexible extension tube
to squirt the cleaner through an opening where a terminal enters the control case.
It will fog through here and saturate the whole inside of the control-including
the two critical sliding contacts I mentioned. Unlike old carbon tet, modern contact
cleaners contain a lubricant and an anti-corrosion coating in addition to the corrosion
solvent; so their effect lasts much longer.
"I'm glad to see that cleaner for glass and plastic. Lots of radios have plastic
dial covers, and of course, most TV tubes now have bonded faceplate shields. Many
cleaners for glass will attack and fog plastic - as you well know. It's a comfort
to have one cleaner that can be safely used on both."
"Okay, let's go on to 'Cements and Glues,' " Mac said. "Here, of course, is a
tube of our old reliable speaker cement that does many more things than repair cracks
in speaker cones. Fixing dial cord knots, securing the pointer on the cord, and
fastening loose loop and coil windings are a bare beginning or the uses for this
versatile clear cement. But it's not so hot for repairing broken cabinets, although
many try to use it for that. This plastic cement or this Bakelite cement should
be used to repair cabinets or knobs in accordance with the material of the broken
item. Properly used, either will create a strong, durable, inconspicuous repair.
Since not all cabinets are Bakelite or plastic - yet - this wood glue still comes
in handy quite often. And this rubber-to-metal cement is excellent for fastening
loosened rubber drives back on their shafts or wheels. Finally, these two tubes
contain an epoxy cement and catalyst that combine into a glue coming as near to
bonding 'anything to anything' as you will find. We don't need it often in service
work, but it's sort of a reserve heavy artillery that can be called in when nothing
else will do a heavy-duty cementing job.
"Under 'Lubricants' we have a light machine oil for general lubrication, tuner
lube for TV tuners, Lubriplate for sliding dial pointers and for tape-recorder and
record-changer mechanisms, a fiber grease that will cling to a rotating gear or
wheel in spite of high temperatures, and this silicone grease for providing a good
heat-transferring bond for mounting power transistors."
"That leaves only the 'Miscellaneous' section," Barney noted.
"Yes, and there aren't too many items here. Of course, this cabinet repair kit
embraces several individual stains, varnishes, shellac sticks, etc., with which
we can work a scratch out of just about any kind of wood or plastic cabinet. Another
item we both like is this pressurized can of refrigerant gas that is marketed under
various trade names such as Circuit Kooler, Zero Mist, and so on. A shot of this
gas will abruptly drop the temperature of a suspected item in an intermittent set
and often make that component reveal itself as the cause of the trouble. We don't
hold our fingers in the spray and freeze them, though, as the salesman told us one
of his customers did!"
"Practically all chemicals can do physical damage if used carelessly, I reckon,"
Barney observed. "But all you have to do is read the instructions and warnings on
the can and then follow them. If they say: 'Don't use near an open flame'; or 'Don't
inhale fumes'; or 'Keep away from eyes'; or 'Avoid prolonged contact with skin';
or 'Highly flammable,' assume there's a good sound reason for the warning and heed
"See that you do," Mac said. "At any rate, that winds up our little seminar on
chemicals. Keep your eyes open for additions to this shelf, though; I'm sure there
are others that belong there."
"Will do," Barney answered, getting off his stool and stretching, "but if you
will allow me to coin another phrase - I'm full of 'em today - I think you should
entitle your lecture 'Better Things for Better Servicing Through Chemistry!' "
Posted October 6, 2022
Mac's Radio Service Shop Episodes on RF Cafe
This series of instructive stories was the brainchild of none other than John T.
Frye, creator of the Carl and Jerry series that ran in
Popular Electronics for many years. "Mac's Radio Service Shop" began life
in April 1948 in Radio News
magazine (which later became Radio & Television News, then
World), and changed its name to simply "Mac's Service Shop" until the final
episode was published in a 1977
Popular Electronics magazine. "Mac" is electronics repair shop owner Mac
McGregor, and Barney Jameson his his eager, if not somewhat naive, technician assistant.
"Lessons" are taught in story format with dialogs between Mac and Barney.