70s strat pickups/magnet insulation?

[lexluthier72]

Hey Folks,
among my projects to rewind is an old 70s strat bobbin. My question is: Did they simply clear coat the magnets to insulate them from the coil, or, was some sort of tape used over the magnets? If a clear coat, what type? Id like to get as close to stock as possible....
-Erin

[big_teee]

I just rewound a 74 strat coil.
It had 42 ga. Plain Enamel wire.
The Coil had been dipped in a dark Lacquer.
This was supposed to protect the wiring from shorting out to the magnets.
Also the Lacquer is supposed to help make the magnets stay put.
It didn't work to well because the flatwork was badly warped.
I've read one of the problems with the CBS pickups, the magnets were loose in the flatwork, and mine wasn't very tight.
Now a days I spray all single coil Rod magnet Pickups with Krylon Clear Lacquer.
I then tape all rod magnet single coils with scotch magic tape.
Only one wrap around the rod magnets, does the trick.
I don't like my wiring shorted to the magnets, and the tape seems to be the only sure cure.
Good Luck,
Terry

[David King]

I just bought a bottle of something called Corona Dope which might be a reasonable alternative to the lacquer dip Fender might have been using. The Dope is thick and goopy and a dark blue color. I haven't tested it yet.

[lexluthier72]

Terry,
Thanks for the tips! Im betting the "lacquer" they used was merely darkened nitrocellulose. David, let me know how the Corona Dope stuff works. I have a set of single coils coming that have been potted in Q-dope....I have to "undo" them...the covers reacted with the q-dope and are "melting" doh....(id test the reaction to pickup covers on that stuff. =)

[big_teee]

The Q-dope doesn't sound like it's for me.
To start with I don't to dip the bobbins in anything that is going to turn out blue!
The bobbins need some protective coating, when it comes to potting, the pickup industry standard is Wax.
Easy enough to do and it stays put until it's remelted.
If a pickup is encapsulated, it would be potted in epoxy, but I have no experience with any of that.
Later,
Rock Steady!
Terry

[lexluthier72]

If I were to pot a pickup, it would be in wax only....I like the idea of being able to possibly repair things in the future, service cement (ie, q-dope, c-dope, epoxy) do not allow for any sort of repairability.

[David Schwab]

If I were to pot a pickup, it would be in wax only....I like the idea of being able to possibly repair things in the future, service cement (ie, q-dope, c-dope, epoxy) do not allow for any sort of repairability.

The c-dope is for the magnets before you wind. The question is; why would you have to repair a pickup?

If you encapsulate your pickups in epoxy you can't repair them, but then they are protected from most of the things that will break them, so they wont need repairing. I have a Bartolini Hi-A pickup I bought back in 1977, and it works fine after all these years. I have some old EMGs which are fine too.

I encapsulate most of the pickups I make. I also wax pot them first.

[lexluthier72]

The C-dope I understand....As to why I would have to repair a pickup....some customers do some pretty stoopid things....I once had a guy who installed an old bartolini in a cavity that was really too tight for it to go into correctly...well, he forced it in, and sliced the wire on the edge of the route.....leaving about 1/4 inch nub sticking out of the pickup.....I was able to route away some of the epoxy very carefully, and expose another 1/4 inch of lead wire, to put a new lead on his pickup....I have a "project" set of melody maker pickups coming that have been potted in Q-dope and then put into the covers....The Q-dope reacted with the plastic covers, and melted the covers, plus, the covers were modified to fit on a humbucker base...I intend to use these in a 65 Melody Maker I am restoring....again....I have to "repair" the original pickups....remove the covers from the working coils without damage to the coil, and put them into new covers.....again, people do some pretty stoopid things....
I understand the use of Epoxy, and you are correct that they rarely need repair, but I must get the majority of DIY customers that always seem to stick the proverbial fork through their pickups....doh. I will say that I do like the challenge of trying to keep something working that has been previously mucked with. =)
My personal taste is I like wax for the simplicity and almost no mess involved, also...no toxic/annoying fumes to deal with. One question I do have is, if potted in another material (ie, epoxy, sanding sealer, urethane) How does that affect the bobbin, or other parts if the pickup does ever need a rewind for some reason...?

I also had an early Bill Lawrence "marauder" pickup go dead on a customer....basically tossed it in the trash, and made a new pickguard, and put in a Dirty Fingers....

[Corona Blue]

big_teee wrote:

Now a days I spray all single coil Rod magnet Pickups with Krylon Clear Lacquer.
I then tape all rod magnet single coils with scotch magic tape.

Hey Terry-
This kinda harkens back to our recent discussion of the Fender pole pieces a little bit... not to hijack the thread, but it would be interesting to know if the early (50's) pickups were also lacquer dipped or just waxed. Anyone know?

I have experimented this year with my insulating technique using wax, lacquer, and a combo of both for my old school winds, and I think I'm hearing a little difference in the textures of the "percussion envelope." To my ear, the paraffin/beeswax quick dip (before winding) by itself sounds the best and "most accurate" to an early Fender pickup, but it does not offer the tough insulating benefit of lacquer or tape. Once in a while still I'll get a short to a magnet... so lately I've been using nitro lacquer and then the wax too. Once the lacquer has dried overnight, I just lay the assembled bobbin in the molten wax for 1 second and remove. The cold pole pieces don't have time to heat up and so a thin wax layer hardens on them instantly. Seems to be a good compromise sonically and no problem with shorts. It's an extra step though, and maybe not practical for a production shop.

Allen

[David King]

Allen and Terry,
This old discussion provides a lot of data you might want to sift through regarding effective and ineffective magnet insulation techniques.
http://music-electronics-forum.com/t2530/

[Rick Turner]

In addition to the possibility of coils fully shorting to bare Alnico magnets, the inner wraps of a coil also capacitively couple to the magnets. Not much to do about it other than simply recognize it.

I vacuum wax pot and then epoxy pot my humbuckers, and I use carbon paint shielded plastic covers because they are less microphonic than metal covers, even with all the potting. I never have pickups go bad in the field. It just doesn't happen.

[lexluthier72]

Hey Guys....Great info! Rick- Great to see you on this forum....Im a long time fan!

p.s.- Im finding in my use of the Search feature, that alot of this information is buried in other posts with Headings that arent so clear....Maybe we could make some of this basic info a sticky?

[Corona Blue]

Im finding in my use of the Search feature, that alot of this information is buried in other posts with Headings that arent so clear....Maybe we could make some of this basic info a sticky?

+1

[David King]

Well you can copy useful posts or links to good topics and add them to the FAQ sticky.

[Joe Gwinn]

I just bought a bottle of something called Corona Dope which might be a reasonable alternative to the lacquer dip Fender might have been using. The Dope is thick and goopy and a dark blue color. I haven't tested it yet.

Corona Dope is not Q-Dope. Corona Dope is a heavy rubber composition that one coated the outside of a high-voltage transformer (such as the flyback transformer in a cathode-ray tube TV) to prevent corona breakdown and destruction of the transformer.

There was a long thread on suitable ways to coat or tape magnets before winding to prevent subsequent shorts. The thread also went into how to make your own Q-Dope by dissolving polystyrene packing peanuts in toluol.

I doubt that Fender used Q-Dope. It really won't keep the wire from swimming through the film unless you dry the bobbin for a week. Q-Dope is intended for gluing the wire of a RF coil in place, and insulating the wire as well.