I've read a bunch of references recommending Deoxit for cleaning the contacts on old equipment. I asked for this product at a well stocked locally owned hardware store
that always has everything I ever ask for but in this case I came out empty handed. They recommend I use a product called QD Contact Cleaner. It's a quick drying zero residu,e plastic safe spray can containing
n-hexane, methanol, Hexane isomers and some other solvents. Does this sound like what I should be using? Told you I would have a bunch of questions.
I've used QD Contact Cleaner quite a bit, never had any problems with it.
As far as I know, you will only find Caig Deoxit at electronics wholesalers or online? I do not believe hardware stores stock it.
Some of the high end audio places stock Caig products and the price is rather high-end as well. DeOxit ain't what it used to be and many equivalent cleaners work just as well.
I could use some pointers on where exactly to apply cleaners, and where to follow up (or not) with lube. For example, the variable capacitors; do you spray the plates, shaft, and bearings liberally with cleaner? Followed by lube on the shaft ends? How about pots. Cleaner only? Yeah, I'm dense. It took me years to master copy and paste, and I still don't comprehend "cut." And my brother is a programmer! Wish someone would write "Radio Resto for Dummies" but the trial lawyers would have a feeding frenzy.
On a typical 30s-40s variable capacitor the primary electrical contact is is a little springy fork looking thing that fits around the movable shaft, usually in the center. That's the main one although there is some degree of electrical contact in the front bearings and at the rear pivot point. There are numerous variations but generally those are the points that want to be cleaned and lubed. The bearings require something thicker for long term lubing...the springy thing just wants to be clean with a light lube.
The plates don't need anything unless they are visibly nasty or corroded. In fact any "cleaner" that leaves behind a residue may affect the capacitance value. Bottom line is that the tuning cap should be clean and the moving contacts lubed for smooth and noiseless operation.
One piece that I'm anal about is the little Bakelite or phenolic strip that isolates the stator plates from the frame. Crud=leakage and with these caps often mounted 'vertically' the crud settles on the inner side of that bottom insulator.
I agree with all that has been said. Even after a good vacuum job, and spray with deoxit, a variable capacitor will probably still be enough grease on the ball bearings to go around.
If you go the route of removing it entirely, you can soak it in paint thinner, carefully remove the slivers of mica on the trimmers clean them and set them aside, they are very fragile but still OK if split ; spray out all the crud and boil the D**n thing in water if it's really really nasty, and replace the micas when it is all done. Do this in a well ventilated room or outside. You have been warned.
A tiny dot of lithium grease is all that is needed to smooth out the ball bearings after this is done. Of course everything needs to be wiped down and dry out overnight before you put it together again. Only adjust the set screw in the back unless you absolutely have to, and back off the surrounding nut first. Unless there has been trauma to the shaft, this is uusually not necessary.
A little squirt of WD-40 should release any binding on the bushings after all this is done. A piece of paper will reveal any places where the rotor plates short the stationary plates. Usually on the ends you can correct this easily. Use an old fashioned VTVM ohmmeter to find shorts. A Digital meter will drive you nuts trying to find it.
Incidently some of the rotors may have two or three sub leaves which can be used to fine tune the tracking of the set, but this is a whole other matter. Somebody has gone there before, just can't recall who.
Pots, in general, blast away with Deoxit including the shaft bushing, rotate back and forth a few times and let it sit for a few hours. Same thing with band switches.
Thanks guys. Now how about where a lighter, penetrating lube/oil is preferred over lithium grease? I'm got a yen to poke that needle applicator somewhere. (Try to resist the obvious.)
Hope I'm not hijacking your thread Elrick. These seem like natural follow-ups to your original query.