Magnet insulation

[Possum]

I thought I'd throw this out there and see what washes up on shore. As a matter of course I tape my magnets to insulate them. I've tried lacquer dips of various types and brands and no matter how loose I wind the coils short to the end poles. Nail polish the same thing. I have my old Fralin pickups laying here, the ones that got me into pickup making because they would never give it up through any guitar or amp I tried them through. So I cut the coils off, so out of curiosity I put my ohmeter probes across the magnets and no reading. I pushed real hard tried to dig into them and no reading. The magnets don't look coated at all, so I took an exact knife and scraped into and sure enough they ARE coated with something that I could chip off. Whatever it is, its as hard as a super glue coating, and is matte finish, not gloss. I am real tired of using tape and looking for ideas what they might be using. I've research electrical varnishes and lacquers and sure they are made but you have to send out and RFQ and no one will talk to you unless you want to buy 50 gallons of the stuff, and I'm not even sure it would work either. I found some stuff made by Dolph but again, they don't answer email and you can't find anyone who will sell you one can of the stuff to try out. So looking for ideas. Its has to be a hard almost invisible finish , hard as super glue, be easily wiped off and not thick so you don't have crap all over the magnet tops and flatwork. Super glue would work but how would you apply it without gluing your tongue to your knee in the process. Joe Gwinn suggested marine epoxy paint but you'd have to mix up enough to dunk the pickup in so there would be alot of wasted product and probably too thick to use. Ideas?

[mick]

I'm glad someone has mentioned this because I was about to ask..., just wound some strat pickups several times ( PITFA that was ), same thing no matter how loose it was wound it shorted to the outside poles? was thinking of some kind of poly laquer? but not sure if it would work ? there must be something ,

And can I mention Q for a moment , mine seems to be around the 2.4 even on low wind numbers? this is with strat pickups , I was thinking that maybe the tape was something to do with it ?

Mick

[J S Moore]

How about vinyl sanding sealer? Takes about an hour to dry and I am sure you can make it thin enough if it isn't already. Apparently it leaves a nice finish on the pickup as well. I read on SK's site that he uses it for potting and it will probably work for what you want.

[mick]

"How about vinyl sanding sealer? Takes about an hour to dry and I am sure you can make it thin enough if it isn't already. Apparently it leaves a nice finish on the pickup as well. I read on SK's site that he uses it for potting and it will probably work for what you want."

I Thought about the stuff they use on floorboards after they sand , that stuff is pretty hard but it could be too glossy? I'm not sure if it's the stuff you mention .

Mick

[mick]

Just had a thought on this , the mags have a very slight oily residue on them , if it's not wiped off properly the laquer won't stick properly , maybe I need to dip my mags in some kind of cleaning solvent ?

Mick

[madialex]

Just had a thought on this , the mags have a very slight oily residue on them , if it's not wiped off properly the laquer won't stick properly , maybe I need to dip my mags in some kind of cleaning solvent ?

Mick

Hi Mick, I use Deft Lacquer sanding sealer and I dip the pickup in either alcohol or when i'm out I have used fingernail polish remover to clean the whole bobbin mags and all. Just rinse it off quick, let it dry and dip them in the sealer, it leaves very little shine, it actually makes the bobbin look better IMHO. Takes about an hour to dry then you are good to go. I have baked them in the oven at about 140 to 150 for about 10 minutes to dry but I stress, be very careful, they put off a good deal of fumes when you do that, safest way is to just let them dry, hang them on some wire but make sure you wipe off the drip or it may dry like that

[Spence]

Use good old fashioned nail varnish. It's cheap, 1 bottle minimum order and dries in minutes. i opt for clear nail varnish though I have been known to use red and black. ( On the pickups that is. Just want to make that clear, so there's no confusion. Oh bollocks what have I saiD ...?... )

[mick]

Do you tell your mrs it's you who takes it and not the kids ?

[Possum]

Deft??

So you're not getting pole shorts with this stuff and its virtually invisible when dry? Since you've been to Fralin's shop did you happen to notice what they're using? The stuff they're using dissolves in lacquer thinner so it can't be anything too exotic.

[Possum]

Deft??

Where do you buy this stuff, Lowe's , Ace?
Nail polish never worked for me, its too soft, especially the sparkle pink with little stars in it :-) Seriously though I could never get it to work and tried various brands.....

[mick]

Hmmm , reminds me of the time I went out to the shops ( I usually go around barefoot ) with blue sparkle nail polish on my toes , I can thank my 2 daughter sfor that one , man did I get some looks...

Mick

[Spence]

Do you tell your mrs it's you who takes it and not the kids ?

Nah, bugger that. I never tell her anything. She has wondered why I never wear sandals when she's around though.....

[Joe Gwinn]

So looking for ideas. It has to be a hard almost invisible finish, hard as super glue, be easily wiped off and not thick so you don't have crap all over the magnet tops and flatwork. Super glue would work but how would you apply it without gluing your tongue to your knee in the process. Joe Gwinn suggested marine epoxy paint but you'd have to mix up enough to dunk the pickup in so there would be alot of wasted product and probably too thick to use. Ideas?

Don't forget the part about thinning the epoxy varnish so it'll go on thin.

Another alternative is thinned urethane spar (marine) varnish, first air dryed, then baked in a toaster oven, to ensure that the film is fully hardened before attempting to wind. Don't forget to wash things in acetone first, to remove all grease before attempting to coat the magnets.

Why marine varnish? Because marine varnishes are the best one can buy at retail, and although they are expensive compared to non-marine products, it makes no difference in the quantities used on pickups.

Why does the film have to be so hard? Because the pressure is very large. Let's run a numerical example:

Take a 8,000-turn coil wound with #43 wire. The winding tension is something like 26 grams. The end magnets are therefore being pulled towards each other with a force of (0.026)(2*8000)= 416 kilograms, or 915 pounds. The effective area of each magnet bearing the load is about 3/16" by 7/16", or 0.0820 square inches, so the pressure is about 915/0.082= 11,157 pounds per square inch, on average. This well exceeds the strength of many plastics, both initially and especially over time as the pressure causes the inner wires to creep through the film

The pressure will be reduced as the bobbin crushes slightly and as the wires in the winding slide about a bit, and/or due to a loose wind, but still it's easy to get large numbers, so the coating must be quite hard right from the start to survive.

[madialex]

Where do you buy this stuff, Lowe's , Ace?
Nail polish never worked for me, its too soft, especially the sparkle pink with little stars in it :-) Seriously though I could never get it to work and tried various brands.....

Hi Possum, sorry but I wasnt at Lindy's shop long enough to see a lot of things, though I was trying to take in everything I could. He mentioned a crazy glue he uses on the single coils for the magnets that has no fumes?? I didnt catch the name of the stuff but as far as the coating it didnt look like anything was on the prep;ed bobbins ready for winding if it was it was clear.

I got my deft from Lowes, a quart was like 4 bucks, its clear lacquer sanding sealer. I just dip the whole bobbin in for a few seconds and hang them to dry. As I said you will have to watch for that last little drip that will dry on the end if you dont wipe it off. If you dont want any shine on the flatwork at all just wipe the flatwork off after a few minutes and leave it on the mags.

To my knowledge I have had no problems with the coils shorting yet.

[Spence]

Something that springs to mind:

I seem to remember Possum telling me that the magnets are sometimes a bit loose in the flatwork and the effects of lacquering help to stick it all together. OK, that may be where the problem is. I say this because if the flatwork moves on the magnets, it will get trapped between the flatwork and the magnets on the end poles. in the process the coating on the wire is stripped and so is the lacquer on the magnets.
This oversize/undersize issue with bobbins and flat work is a right royal pain in the ass. In order to get around this problem, I always resort to using a set of reducing punches.



These are readilly available at Micro mark.

http://www.ares-server.com/Ares/Ares...oduct&ID=82390

Obviously don't use these on the side of the flatwork that shows.

Lacquer after.
My personal choice is Fiddes Bonehard Lacquer. I guess by the name of it, it's nitrocellulose with viagra in it !