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kentfielddude
Regular Member

Joined: 09/05/2019
Location: United States
Posts: 91

Posted: 03:50pm 04 Aug 2026

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I'm trying to figure out what I need to finish the primary winding and prepare the core for the secondary.
The enameled wire got some small nicks in the enamel on the outside windings. What's the best red insulating varnish to use to repair it?

What type of mylar should I buy?
What's the best way to connect my two split windings together?

Pete Locke
Senior Member

Joined: 26/06/2013
Location: New Zealand
Posts: 185

Posted: 07:16pm 04 Aug 2026

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I've had great success using nail polish/varnish to touch up nicked copper wire enamel. It's also good (using clear nail varnish) for coating the copper side of hand etched PC boards preventing oxidation of the tracks.
Cheers
Pete'.
Edited 2026-08-05 05:18 by Pete Locke

Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 683

Posted: 10:05pm 04 Aug 2026

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As Peter Locke says the varnish doesn't have to be red. You could get some varnish from a motor rewinding shop if there is one near.
I just use normal polyester varnish ( stuff for wood) on my transformers. I dip them in a tub when I have finished winding them and leave them for a day or so then let them air dry.

As for mylar tape, I have used Terylene tape on my transformers, I bought some online and it is easy to work with. I would have used fibreglass tape but I hate the stuff it makes me itch too much so I went for the next temperature grade down.

Pete

Solar Mike
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Joined: 08/02/2015
Location: New Zealand
Posts: 1229

Posted: 12:14am 05 Aug 2026

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On all my inductors and transformers I dip them in a solution of liquid polystyrene, then hang out to dry for a couple of days.

Get couple liters of car spray paint thinner in a metal bucket with a lid, add pieces of expanded white polystyrene, it dissolves very easily, keep adding until the dissolve rate really slows. That's your dipping solution, dries to a hard clear coating. it will soften with heat, but your transformer should never run that hot anyway.

Mike

tinyt
Guru

Joined: 12/11/2017
Location: United States
Posts: 562

Posted: 01:00pm 05 Aug 2026

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I used this. Available from our local Home Depot store.

The beginning of this thread in another forum is how I re-wound the COTS toroid. It is smaller than what you have.
Edited 2026-08-05 23:10 by tinyt

kentfielddude
Regular Member

Joined: 09/05/2019
Location: United States
Posts: 91

Posted: 06:55pm 05 Aug 2026

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There's this 1in 100ft of mylar for $8.20 I Was thinking about getting. They also have thicker as well. They also carry a mylar with adhesive backing.

https://cshyde.com/item/films/mylar-polyester-pet-film/2mil-mylar-1in-100ft

adhesive:
https://cshyde.com/viewitems/ategories-tapes-with-adhesive-specialty-film-tapes/mylar-film-tape-with-adhesive

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