Insulated copper

Depends on the insulation you need and potential physical abuse.

Magnet wire is usually insulated with a varnish, Formvar or polyurethane. Any good hardware-store varnish should work.

Shrink tubing might work for you.

there's no shortage of options. tell us more. Most paints would work for low voltage.

NT

snipped-for-privacy@gmail.com was thinking very hard :

Electric or heat. :-Z

You need to tell us what you're doing. There's just too many answers otherwise, most of which are probably wrong for your application.

Something very fishy is going on. "Pietro Luigi Carotenuto" is a very uncommon name. Only 38 hits in google. Most of them are university professors or are doing their masters or phd thesis.

And where is a newbie going to get their hands on bare copper wire. Anything you find in a hardware store is already insulated. Anything else you find laying around is probably going to be so badly corroded it won't be worth working with. If it's fine wire, perhaps 24 ga or so, it may be ready to fall apart.

It would be interesting to see the back story to this. But not so much that I'd waste any more time on it.

On Sun, 5 Jul 2015 15:07:08 -0700 (PDT), snipped-for-privacy@gmail.com Gave us:

A-43 transformer varnish has a high dielectric insulation strength.

Otherwise "Kynar" shrink tubing is the top of the line for single layer tubing.

On Mon, 06 Jul 2015 00:48:41 GMT, Tom Swift Gave us:

Strip a stranded line from Home Depot, and you are left with bare copper strands.

Finding bare copper is easy.

Dip in nail polish?

Wasn't shellac used in the "old days"? Or was that just for sealing transformer windings?

scritto:

y or paint.

Thank you to everyone,

I have a lot of copper wires to insulate. So, I just asked some suggestion about some product you probably use. I need it for very low DC level (9-25V ). I have to build a transformer.

Thank you, Pietro

My immediate response is:

"Don't be cheap - buy a reel of enamelled copper wire of the right gauge." - At least you will have a fighting chance of it working.

But if needs must - one way would be to wind bare copper and thin string (maybe heavy button thread) together so the sting alternates with the copper and keeps them from touching. After one layer, paint with shellac which will insulated and set the whole lot solid, wind on a layer of paper to cover the whole layer on the bobbin and repeat. Be sure to soak the paper in shellac too.

Pretty sure that was a very historic way it use to be done (by historic, say earlier than 1950??)

Upto the early twentieth century when chemical varnishes improved the main method was wrapping in strips of cotton or silk. In the mid nineteenth century you could only buy uninsulated wire. The story is that Joseph Henry (after whom we name the unit of inductance) tore up his wife's wedding dress to insulate the wire he used in his experiments.

Perhaps you too can tear strips from your wife's clothing :)

piglet

On Mon, 6 Jul 2015 03:28:00 -0700 (PDT), snipped-for-privacy@gmail.com Gave us:

The link I gave you IS a transformer varnish (the one most of the industry uses, in fact), and it is sold in spray cans as well as in bulk.

On Mon, 06 Jul 2015 11:46:51 +0100, Tim Watts Gave us:

You cannot wind a transformer with bare copper AT ALL!

It MUST use mag wire or it will fail, and that is regardless of what you varnish it up with. (but you knew that too).

On Mon, 06 Jul 2015 11:46:51 +0100, Tim Watts Gave us:

Insulated magnet wire has been around since the early 19th century years.

Correction: after browsing around I now see that this was done by Thomas Davenport inventor of the electric motor not Henry.

piglet

It may have been around, but that does not mean it was ubiquitous.

Sure I've seen some fabric covered wire used in some choke or transformer in an old valve TV I had apart when I was a kid.

Well you can - as long as you takes steps to maintain inter-winding insulation.

But I agree, it is not really a desirable approach for a new component - may as well get some enamelled wire and do it right (or at least more easily).

There is a good chance the wire you have is already insulated. Scrape the end with a knife and see if the varnish scrapes off. If it is not varnished, STOP, buy or even salvage some insulated wire. You do not want to wind a transformer with uninsulated wire. After you wind your transformer with insulated wire, It is a good idea to dip it in varnish and bake it at 300*F for 45 minutes. Mikek