Mythbusters Vintage Magnet Wire.

[Possum]

I wanted to post this general info I got from lab examination of 14 examples of mostly vintage wire and several examples of modern wire, some not available anymore.

Vintage wire differs from modern in ohms per foot. For example some later period PAF wire was 1.876 ohms per foot. A nearly identical modern wire, the new black wire from Elektrisola measures 1.702 ohms per foot.

Tensile strength in modern wire is higher than vintage wire because the copper is more pure, and the wire is better annealed than the old stuff. The old stuff broke more easily than modern.

Insulation is very different. I read from Tim Shaw that he found the insulation of old wire was thicker than modern. This isn't what we found at all, just goes to show you, don't believe anything you read from old work done years ago, probably before laser measurements were available.

Example, from a 1960 PAF one of the best year examples for tone, bare wire was .061mm, while O.D. was .066mm, an insulation of .005mm thick. Here's where some of you are going to choke, a spool of American Wire Corp. black wire from about 2004 or so, bare wire diameter .062mm, with O.D. .072mm, and insulation of .010mm thick.

I always thought the AWC wire was a vintage correct wire but it turns out its a nearly heavy build modern PE. I have some that has even thicker insulation than the conservative sample I sent. Its good wire but isn't like anything in any of the vintage examples I sent out except for an oddball sample from a 1965 Cort bass that had an astonishing .011mm thick insulation and a bare wire of .059mm.

Most of the vintage PE averaged about .005mm thick insulation. Modern REA wire was .008-.010mm thick insulation.
Modern heavy formvar 42 bare min. is .061mm with O.D. of .076mm so an insulation of .015mm so the AWC sample isn't quite heavy build, but gets fairly close, I'm sure some of the other samples I have are heavy build over slightly over, I sent them the most normal AWC stuff I had to see how it compared to vintage.

Other things they check were concentricity (roundness) and they said they were amazed how round the old stuff actually was.

Ohms per foot on all the modern stuff was lower than vintage, because of the more pure copper and because of the high quality anneal process.

The vintage PE samples were from '51, '58', '60,'56, '62. '65.

I was told they can do the old wire but not a minimum order, so you'd be looking at probably 1000lbs if you wanted to match the stuff that was made back then. The closest modern wire to vintage was some Essex stuff I had left over from about 2003 but it wasn't a match either.

They told me the insulation for PE is the same as back then, but weren't 100% sure as the coatings are made by a different company, so dieletric effects could be an issue and probably the modern PE versions are better insulators than the old stuff, I bet. Also that the company that makes it dislikes making the stuff and don't like doing small batches..

So, vintage wire was noticably darker sounding than modern wire, I pretty much knew that already from making copies of my Patent pickup coils and putting PAF parts into both, the modern coils are really much brighter sounding. The theories about "micro cracks" in the insulation because of aging making the coils sound darker partly falls apart with this data in hand, coils do get darker over time and i've heard this in my own PAF work from only 3 years ago. Why, is anyone's guess.......

[cryptozoo]

Very interesting info, Dave. Thanks for sharing. How about a group-buy order for 1000 lbs?

[Possum]

.....

Well, there's a problem there, WHAT model of wire do you go for? There are variations and probably none of us have ever wound with pre-1965 wire and maybe you wouldn't like it. It would be a gamble and an expensive one too. I'll ask just for fun what they would charge and what minimum. MWS says their minimum for stock PE is 60lbs but this is way different.....

[cryptozoo]

And based on what you said above, even if you got them to match the size and insulation, the properties of the modern copper could / would have an effect.

[JGundry]

Were the modern wire samples you sent stripped from an already wound pickup or were they straight from the spool?

[Dave Kerr]

Cool stuff, Possum. Just a minor correction - when you say

bare wire was .061mm, while O.D. was .066mm, an insulation of .005mm thick.

wouldn't the insulation thickness really be .0025?
High tech ASCII illustration:

____________________
insulation .0025
____________________

wire .061


____________________
insulation .0025
____________________

[David King]

If the old samples had come off old pickups isn't it possible that the wire had seen a bit of stretching to account for the higher dcr and brittleness when compared to the new wire off a spool?

That would be funny if modern essex spn is the closest to old PE. I'd be pretty well stocked!

[JGundry]

If the old samples had come off old pickups isn't it possible that the wire had seen a bit of stretching to account for the higher dcr and brittleness when compared to the new wire off a spool?

It might also account for the thinner build if it was felt tensioned. If the samples came out of Gibson pickups they were felt tensioned. In fact they were felt tensioned in two stages usually. One felt as it dereeled and one felt at the wire guide. The amount of tension and twists and turns the wire makes during winding I would think would affect the final rest results of both the build and the wire hardness.

Also did you get the ohms per foot and single build tolerance for 42awg PE and do the old and new numbers fall within that tolerance? Are the differences a tolerance issue or a materials composition issue?

[Spence]

I have done a little video where you can see the flakey surface on 50's plain enamel. The same applies to old heavy build formvar. This is a much bigger factor than these micro cracks I keep hearing about.
The modern coatings are mostly the same stuff but they're applied in a completely different way. When you look at them under the scope, they're as smooth as a baby's bum just like poly coatings.

Another thing to consider is the engineering tolerances for a given wire gauge are so large in relative terms that some 42 AWG is closer to 43 AWG. This manifested itself in a lot of 50's P90s that, for the standard turn count, came out at a higher reading than you would expect.

On the other side of the coin, I had a 12lb spool of 43 AWG that was closer to 42 AWG and yet was still within spec. Took a while to find things to use that up on.

[EtLa]

On the other side of the coin, I had a 12lb spool of 43 AWG that was closer to 42 AWG and yet was still within spec. Took a while to find things to use that up on.

Same thing happend to me and i asked my supplier if he sent me 42.5 by mistake.

[Sweetfinger]

an oddball sample from a 1965 Cort bass

That is certainly an oddball. IIRC Cort didn't come into use as a name until the late 70's. Westheimer founded Cor-tek in '73 or '74. Sure about the chronology?

[Possum]

....

Alot of good questions. All the modern wire was off spools, but there is stretch there too, REA spools have been notorious for this in the stuff I got, would start out skinny, get fat then skinny at the end of the spool by a large amount, I sent stretched and unstretched samples off their spools, yet its still very modern fat insulation, high tensile strength. Vintage winders didn't wind very tight, but yes stretch is accounted for, the tensile strength still shows differences from crude annealing and he also told me modern wire is more annealed, more steps. Yes, if you had this stuff made today you're still stuck with way more pure copper. The insulation thickness is a total, not divided by 2, they actually didn't give me single thickness just bare wire and O.D., so go by that. Yes modern coatings are done way differently, in many coats, many annealings. Tolerances are large, the smallest wire of the bunch is the new black wire MWS carries, stuff makes real small coils but its all you're gonna get 'til they run out, I don't like it in bridge pickups. In the PAF examples I gave them 3 from '62 and '60, 2 were wound normal tension, one low tension yet all the measurements were the same, same tensile strength and diameter. Vintage wire just isn't as stretchy as modern and breaks easier. They told me AWC uses cruder methods and aren't able to do consistency very well and you sure see that in all the stuff of theirs I've collected, I have some that has real small bare wire and huge insulation, makes big coils with higher DCR, kinda useless stuff. Unfortunately I couldn't find a sample from WB's '67 wire that I have to compare with the '65 sample, he may be the only guy with any useable vintage wire I know of, but I'm guessing its not PAF type specs if something changed in '65.

The one thing that occured to me, is way back 8 years ago Alex at Guitar Jones, carried PE from Korea. That stuff has real thin insulation and I bet may be the only close thing to vintage wire. He quit carrying it because they wouldn't pack it right and ten pound spools would show up with dents in the coil and the wire would break in the dents, I still have a tiny bit of it left. Their 43 was horrible, you had to use zero tension almost or it would short out but no problem with the 42. It was on the small side of tolerance but I really liked how that wire sounded. I bet someone still makes it over there, how to find them and how to get it, might be worth a bulk purchase there maybe.

[JGundry]

I think work hardening probably comes into play with the wire after it has been wound on a bobbin. The coating does deposit on the felt tensioners as well so that probably comes into play also.

If we are talking Gibson vintage pickups some are wound very tight and some are pretty sloppy and appear pretty loose when the tape comes off the bobbin. The sloppy ones seem pretty loose when you unwind them but that is largely because the coil has collapsed on itself during the wind and while unwinding. At this point I have had quite a few vintage Gibson pickups come in for repair or rewind and most are pretty well tensioned coils. Certainly enough tension to stress the wire as it went on the bobbin a bit. How much effect it would have on the wire you would only know from a before and after test.

[Possum]

....

He did tell me specifically the wire in those days was somewhat poorly annealed, add that to not pure copper and its a drastic difference. Pretty much the wire of that era even back then was considered crap by engineer types. I've seen overall O.D. change noticeably in just one coil too. Too much to be accounted for by stretching. There is no modern equal of any of that wire.

Keep in mind that much of what he told me about vintage wire was before I sent him the samples. He knows alot about early methods and nothing about the samples surprised except that concentricity was of a higher standard than he'd thought.

[tonedeciple]

I another thread, I mentioned my idea of forming an organization of pickup makers both large and small, specifically to arrange a bulk order of vintage correct wire. It would more than a group buy as an organization usually has more clout. However, this thread indicates the difficulty in actually doing this. It doesn't look like the insulation would be too difficult, but the bare wire might be.

At this point, I'd be interested in a group buy of 42 and 43 awg SPN. Just because it would make life a bit easier instead of spending hours searching and emailing sources for price, quantity minimums and specs. We might even get a better deal (under $30 a pound). I realize this might not be of much interest to the PAF replicators, but with these sample results, a correct thickness SPN or HPN, would do the trick for the rest of us.