Magnet wire short to alnico rods on stacked single.

[Stratz]

I wound the bottom section of a stacked Tele neck pickup and although I lacquer dipped the bobbins twice I didn't insulate the rods with tape like I normally do.

Does anybody know what the effect of a short on the bottom non sensing coil will have on the overall tone and/or hum cancellation?

Thanks.

[David King]

Any closed (shorted) loop of copper in the vicinity of the sensing coil is going to suck some treble out of the coil.

[big_teee]

Is it the continuous wire model that we discussed on the BC?
Or are both coils wound separte with the finish leads tied together?
If it the continuous, and that would put the short in the middle of the pickup, then I think that would be a no go.
If it the second both coils wound the same and it is the start lead that is grounded, I don't see a problem with it.
I had a SC Tele pickup that was shorted near the start lead that was grounded, and it worked fine.
I ended up rewinding it, just for the hell of it, because I knew it was Shorted.
T

[Stratz]

Thanks David. I tried it in my mule and it actually sounded pretty good but it could have used a little more highs.

Terry it's 2 separate coils both wound in the same direction.
I wired it and up with 4 conductor (Duncan color code) and I get the individual coil readings as they should be (green/red-black/white but I can get the full (or almost full) DCR reading when testing the black start and white finish leads of the top (sensing) coil.

I'll have to strip it, tape the magnets this time and rewind it. I think I'll have a pretty good sounding Tele neck pickup.

Pretty much a Duncan Stack clone. Easy to build.

[Stratz]

All done. Taped the rod magnets this time. No shorts. Sounds good..... a lot better than I thought it would.

[Joe Gwinn]

The reason that lacquer failed and tape succeeded is the large pressure imposed by the coil winding at the bottom of the coil.

For a rough estimate of the pressure, assume 5000 turns at a tension of 25 grams: (2)(5000)(25)= 250,000 grams, or about 550 pounds. Now, this is not achieved because the forbon gives a little, et al, but still that's a lot of pressure.

The pressure suffices to cause the inner turns to swim through the lacquer, even if it's fully cured, which isn't usually the case (nobody can wait that long). Tape is thicker and cannot so easily be penetrated by the wires.

There was at least one long thread on this issue.

[Stratz]

I knew there was a lot of pressure on the rods but I the never thought of it in the way you described it.
~550 pounds is quite surprising.

I've always used polyimide tape on my single coils to keep the wire from shorting but the winding area was ~7 mm and I only had 6mm tape which would have taken at least two full wraps to cover/insulate the rods entirely.

The tape was also almost 3 mil thick with the adhesive and I needed all the room I could get so I decided to go with the double coat of lacquer. I'm not surprised it shorted.

[David Schwab]

...I only had 6mm tape which would have taken at least two full wraps to cover/insulate the rods entirely.

That's how I do it. I use thin masking tape. It doesn't add much space.

Or, lay down some of the tape on a smooth flat surface and cut it with a razor blade and ruler.

[Spence]

If you want to use lacquer I recommend you brush on a clear nail varnish. It will give quite a thick coating which dries quickly.

[Stratz]

If you want to use lacquer I recommend you brush on a clear nail varnish. It will give quite a thick coating which dries quickly.

I've tried nail polish, nail hardener and other hard coatings over the years but sometimes I still got shorts.

I just didn't have the correct tape for the job this time so I took a chance.

My father introduced me to Kaptan tape long ago. I should have just waited until I had the proper size....

[David Schwab]

Nail enamel never gets very hard.

[David King]

Kaptan tape comes in many widths and thicknesses. I use the 1.5mil stuff in 1/2" and 16mm which I can always find on eBay for cheap enough. As David mentioned it's easy to narrow it down to a custom dimension if you start wide enough.
I've also made a special arbor that fits the wide packing tape rolls on my lathe where I can slice off a whole section of roll to the exact width I want. Thin, clear packing tape is perfectly adequate for this insulation job.

[big_teee]

I still like my floral wax tape.
Works great. No mishaps with it so far.

[Joe Gwinn]

Nail enamel never gets very hard.

Exactly. It can't, or it would flake off mlady's fingernails in daily use.

More generally, only catalyzed coatings have any chance of becoming tough enough soon enough to be practical. Tape is far more practical.

Speaking of mlady, there is now a catalyzed fingernail gel that apparently lasts just about two weeks, and must be removed chemically. I don't know the details, but suspect that it is catalyzed by UV light. One gets this at a place that does fingernails.

[David King]

L'Oreal holds the patent on this stuff and they are attempting to defend it aggressively. For a while you could pickup cheap knockoffs of the UV curing box on ebay and then one day they all disappeared. I use some uv cured doming epoxy for finishing small parts. The stuff is pretty hard but it doesn't adhere very well. I did manage to buy a 36W fluorescent nail curing box for cheap and I use it from time to time. Full cure takes about 5 minutes but the stuff goes on real thick and then pulls away from a hard surface like metal.