Confusion about KYNAR wire

[leonerd]

I have some reels of fine 30AWG wire, whose insulation behaves quite nicely under application of a soldering iron. It sortof melts off without burning as PVC would do, leaving a clean end. Often I find I can solder straight through it onto a board, or just wipe the tip around the end of the wire to strip off a bit of that insulation before I do so.

I always thought this was "KYNAR" wire, but the more I look around the internet to read about "KYNAR", the less sure I become of this fact. I can't find any reference to anyone mentioning using soldering iron to strip the insulation, or soldering right thought it.

The wire I have is definitely marked "KYNAR", for example this one - https://uk.rs-online.com/web/p/hookup-equipment-wire/2094811/

I feel sure I read somewhere online about a kind of wire whose insulation basically sublimes off under heat of soldering, and I thought I recalled that being kynar, but maybe not.

Can anyone shed light on this?

[jaycee]

Kynar is a very tough plastic insulation that does not melt or shrink back under the heat of a soldering iron. You still need to strip it off before soldering.

The wire you are thinking of is enamelled wire, also known as Verowire or Magnet wire. This is coated in polyurethane, which is mechanically tough and insulative, but can be melted under the heat of normal soldering.

[German_EE]

Verowire, with the little green plastic pen that had the reel on top, there's a memory from the past!

[jpanhalt]

I have wire wrap wire, 30 awg with Kynar insulation that was purchased from Radio Shack and behaves as you describe.   I can run the tip of my soldering iron along one side to "split" the insulation, then peel it back to get bare wire.  Larger gauge (e.g., 26 awg) is more easily stripped with a conventional stripper of decent quality. 

[basinstreetdesign]

Most wire-wrap wire is insulated with a plastic which is branded Kynar so that's where the term came from.  This from the website of a company that makes Kynar, Toefco:

"It is a Polyvinylidene fluoride resin, known within the coating industry as PVDF.  The material is extremely non-reactive with many different substances, and it’s a pure thermoplastic fluoropolymer that is often used when a coating that is extremely pure, strong, and able to resist heat, bases, acids, and solvents is needed. It also creates very little smoke when a fire occurs, and it is easier to melt because its melting point is around 177 degrees Celsius, which is quite a bit lower than most other fluoropolymers"

I've been using this stuff for pcb patches all my career.

[IanB]

The wire you are thinking of is enamelled wire, also known as Verowire or Magnet wire. This is coated in polyurethane, which is mechanically tough and insulative, but can be melted under the heat of normal soldering.

Actually, most magnet wire (all that I have ever purchased) does not have insulation that melts that way. The enamel needs to be scraped off before you can solder it.

If you want magnet wire that can be soldered without first stripping the insulation off you need to take special care that it is described that way in the product details. Otherwise it might not be.

[Berni]

In terms of magnet wire i find that you just need to use enough temperature. My usual soldering iron setting of 300 to 350°C seams to not do anything to the insulation on magnet wire, but if i take it to 400 °C and add some fresh solder to introduce flux that seams to take the insulation off magnet wire pretty well.

The wire i use for bodges also claims to be kaynar insulated. It does not seam to shrink back when heating a non stripped end, but i found that it is possible to strip a small part on the end if you drag the soldering iron from the cut end of the wire back along it, seams like the heat softens the insulation enough for it to be pulled back. Once it cools it seams to stay there. I find it very useful since i don't have to put down my soldering iron to strip the wire.