Magnet insulation

[Joe Gwinn]

Shellac usually won't be as hard as most lacquers. What about a baked-on transformer varnish or even a powder coat? If you need it that tough you'll have a tough time finding something that isn't catalyzed in some way. Bake-on finishes or epoxy are less trouble because you won't be dealing with HAPs.

This is why I was suggesting use of thinned two-part marine epoxy varnish. Available in small quantities from retail sources, and sure to work.

By the way, it is not necessary to mix the whole can at once. One can mix smaller quantities, just so long as one gets the ratio reasonably correct. And use two measuring cups, one for part A and the other for part B, and don't mix things up, or the entire can will be ruined. The cups should be different colors or shapes or both.

Just because that super glue is odorless doesn't mean the fumes won't kill you.

Correct.

[David Schwab]

I think sanding sealers are as a class going to be soft, by design.

This is correct. Sanding sealers are some type of finish, such as lacquer, with zinc stearate added. The stearate is a soft, fluffy soap, making it build up and fill in pores much faster. It also makes the lacquer softer, and acts as a lubricant when sanding.

I really dislike sanding sealers when used for finishing wood. I've always had adhesion problems, and the lacquer ends up chipping off.

[Ruel]

Would potting the pickup help? If it is unpotted then there is the chance that the wire will rub against the magnet as it vibrates and possibly cause insulation failure??????

[Possum]

more, forgot

There IS a hole in the bobbin top and bottom for mounting during winding but if you tape you put up a "fence" that seals off the coil from the interior so no wax gets past the tape.

The two part products are just too much hassle and too much waste for me. Plus expensive, the West stuff I looked at comes in Kits and are like $35. The Varathane looks interesting because it mentions scratch resistance. Whatever Fralin used is lacquer thinner solveable so I'm not sure its super glue after all. I tried some spar varnish and it didn't work either.

No potting doesn't help at all, the shorts happen before potting and its only the end magnets that are the problem. I am just taping the end poles but thats a hassle too. but it works....

[madialex]

Hey Possum

Could it possibly be the wires fault? I mean maybe the insulation is thin and rubbing through at the pressure points? Do you use a lot of tension? You mentioned the way you wind, i'm not sure what you could be doing to cause this? I'm stumped.
Has this been going on for a long time or just recently? Did you switch wire companies?

[Possum]

no...

doesn't matter how I wind what wire how loose, the end magnets will short out. I tried the Varethane diamond stuff and it to easily is punctured by ohmeter probes. I think super glue is the only stuff hard enough to hold up to the pressures of coils. Well that and tape. The stuff on Fralin's magnets you have to really dig in with ohmeter probes and even scrape on it before it will cut through, thats what I want, something that works everytime not just most of the time...

[madialex]

Ok Possum

I'll give Lindy a call on Monday and ask him what it is he was using or still is using. I'm just ultra curious why they are shorting out like that. Maybe I need to check mine every time now myself, but the 3 sets I did yesterday all checked fine.

[Spence]

Just a thought...

Why not use some heat shrink tubing on the outer magnets?

[madialex]

doesn't matter how I wind what wire how loose, the end magnets will short out. I tried the Varethane diamond stuff and it to easily is punctured by ohmeter probes. I think super glue is the only stuff hard enough to hold up to the pressures of coils. Well that and tape. The stuff on Fralin's magnets you have to really dig in with ohmeter probes and even scrape on it before it will cut through, thats what I want, something that works everytime not just most of the time...

OK Possum, is it contagious? I wound a tele neck pickup today, very loose tension and it was shorting out on the right end magnet, if you look at the pickup from the front it is the right end mag. My guess is it was at the start of the wind because the pickup total was 6.73 and checking it at the magnet it is 6.69. I checked it from the end of the wind to the magnet, checking it at the start is only reads about 0.03. I am going to unwind it until I find the problem and see what happened, a big PITA...Grrr..... May be a roll of wire I used, It was one I have not used in a long while but dont remember why I stopped using it...

[Possum]

mmm....

I bet this happens more than you realize, you just forget to check it. When I first started winding I made Lollar's winder which only winds in one direction so I was just flipping the leads to do the reverse coil thing. If you get a coil short and the strings hit any of the poles it shuts the guitar off, so that put the fear of god in me about this stuff. Its not going to really trash your pickup but is just not good to sell them if their shorted out....

[Possum]

me too....

Well I superglue coated the end magnets, medium thick stuff too goopy I thought I nailed it, wound the pickup and of course the end poles are shorted out and the extech shows the pickup got way too dark and fucked up. Whatever Fralin is using he's dipping the whole pickup I can see that. I think its something acrylic or epoxy because lacquer thinner cuts it. Its gotta be something stupid simple, floor polish, floor coating or something you can buy at any hardware store. Don't you need to go to Fralin's on monday and nose around :-) I'll find something eventually that works. Transformer varnishes etc. you see lots of mentions of that stuff but no one sells it. Onward and upward.....

[madialex]

I bet this happens more than you realize, you just forget to check it. When I first started winding I made Lollar's winder which only winds in one direction so I was just flipping the leads to do the reverse coil thing. If you get a coil short and the strings hit any of the poles it shuts the guitar off, so that put the fear of god in me about this stuff. Its not going to really trash your pickup but is just not good to sell them if their shorted out....

The reason I checked this one was because when I tested it for tone it had little to no output, I thought WTF. It was by the way 1 of the stewmac tele neck things that I put together, nothing unusual, press the mags in, press the top on, glue, dry, charge and wind. I made it about 2 weeks ago and wound it yesterday. I fully charged the thing and guess what, when I checked it, very little magnetism left at all, not even enough to pickup a razor blade. Thats what started me checking the whole thing and also discovered the short.

You are right it is way darker than normal, it is not for sale for sure. How many others here have shorts in their pickups and don't realize it? Is it a common thing? Now I'm worried but to this point no failures yet.

[Joe Gwinn]

Whatever Fralin is using he's dipping the whole pickup I can see that. I think its something acrylic or epoxy because lacquer thinner cuts it. It's gotta be something stupid simple, floor polish, floor coating or something you can buy at any hardware store. Don't you need to go to Fralin's on monday and nose around :-) I'll find something eventually that works.

If the coating easily dissolves in solvents it is not epoxy or any other two-part coating, or any coating that changes chemically upon drying (like traditional varnish). Varnish and paint absorb oxygen from the air and cure into an insoluable resin. This is in addition to and independant of drying by evaporation of solvent.

It's sounding like some kind of very hard lacquer.

It might be "polystyrene Q dope", "Q-dope" for short, used on high frequency inductors for radios.

Q dope is made by GC Electronics (used to be General Cement), and sold in 4 ounce bottles for $8: http://www.oselectronics.com/ose_p89.htm.

It's also easy to make: just dissolve old CD jewel cases (and the like) in toluene (from the paint or hardware store). It is very flammable, so some care is required, but aside from that it's pretty benign stuff. Xylene, acetone, and MEK (Methyl Ethyl Keytone) will also work.

Transformer varnishes etc. you see lots of mentions of that stuff but no one sells it. Onward and upward.....

Transformer varnishes are available from industrial suppliers, but be aware that they must be baked. Thinning will also be needed, as for motors and transformers a far thicker coat is needed than needed for a pickup.

With motors, it's traditional to dip and bake the windings twice, to ensure that nothing can move. In a motor, if the wire can move, it wii, and the turns will rub against one another, and will soon wear through, shorting the winding. And let the magic smoke out.

You might be able to buy small quantities from an electric motor repair place, if they like your chops.

[Spence]

Talking of Dope, you might try the type of Dope used to tighten fabric on aircraft wings. It's very hard.

Spencer Aircraft supply this in clear as well as any color you might fancy:

Code is PFI20-A16903 N/T CLR BUTY DOPE

See:

http://www.spenceraircraft.com/catal...ort=2a&page=16

It dries tight and bone hard.

[soundmasterg]

Its too bad you couldn't find some liquid teflon coating of some sort. Just dip the whole pickup in liquid teflon, let it dry, and wind away. Of course, then the whole thing would be so slippery you might hurt yourself.