# Wire wrap wire quality

I am looking at two kinds of wire wrap wire on Amazon.

The first is the better, more expensive kind. It is silver plated and has Kynar insulation.
http://www.amazon.com/dp/B006C4AGMU/ref=biss_dp_t_asn

The second is a cheaper kind. It is tin plated and has PVC insulation.
http://www.amazon.com/Amico-B-30-1000-Plated-Copper-Wrepping/dp/B008AGUDEY

I am going to use it to connect to LED leads, which are tin plated brass, I believe. So I do not see much advantage in using silver plated wire if the LED leads are not as equally noble. Or am I wrong?

The application temperature should never exceed 150 Fahrenheit (65 Celsius), so is there much advantage to Kynar insulation?

Will it be just as well to buy the cheaper wire for this application?

EDIT: Additional info.
I will be using this hand tool for both stripping and wrapping: Jonard WSU-30M
on page 34 here and how to use here

The LEDs are not specifically made for wire wrapping, but they have fairly stiff tin plated brass leads that have a square profile section, although the edges may not be as sharp as purpose built WW leads.
I did not want to solder to the LEDs at all - using wire wrap only. At least that's the hope.

• How many LEDs? What total expected wire use? What desired lifetime? What environment? – Russell McMahon Jun 14 '15 at 21:11
• Several hundred LEDs. I am not sure on wire quantity. Five years or better lifetime. As for the environment, humidity might be a problem - not a climate controlled environment. The temps should stay below 150F. No vibration to speak of. – mcu Jun 14 '15 at 21:15
• OK. Several hundred. Say 300. One foot mean = 3 rolls = $37 in Kynar. Or at$12.35/100 feet =~ 12 cents/LED. If time at $0 Kynar cost is noticeable but < to << other costs per LED. I''d lean towards Kynar BUT, drum roll ... – Russell McMahon Jun 14 '15 at 21:27 • This is what I'd buy. One of these :-): This$15.64 for Jonard R30R-1000 Kynar Insulated Silver Plated Copper Wire, 30 AWG Wire Size, 0.0195" Insulation Diameter, 1000' Length, Red or this or this – Russell McMahon Jun 14 '15 at 21:30
• Wow, somehow I missed those. I only saw the ones that were $60+/1000'. I do wonder how long this offer is going to last though. Their other colors are much higher -$60+. – mcu Jun 14 '15 at 21:36

## 3 Answers

This is a solid "don't know - BUT":

That's a very large \$/foot difference 12c versus 0.9C or ~= 13:1!
However, if the total length needed was under 1 roll I'd be tempted to use the Kynar.
If it was a large installation where cost started to be annoying I'd do some more research. The question needs more information than provided to be answered really well - see below.

The result depends on how you are terminating the wire, which you don't actually say. eg are you using a strip and wrap tool, or manual strip then wrap, or soldering? IF strip and wrap tool - are the LEDs specifically manufactured for wire wrapping use? (pin edge "sharpness" matters).

FWIW - you MIGHT manage to solder through PVC, although not at all recommended. You cannot solder through Kynar. You can wrap Kynar around a heated soldering iron tip and, while it gets very sad looking, it maintains its insulation, more or less - great stuff :-).

Kynar is nasty to hand strip, and 30 gauge wire is somewhat fragile (both are 30 gauge) but OK once in place. If you are soldering it then the tinned copper is fine. If wrapping then you are presumably stripping it first then relying on the wrapped pin to wire contact. WW pins have sharp edges designed to bite into the wire. LED pins maybe be of square section are not intended to do this (AFAIK). Any help you can give an unsoldered join may keep it alive years on (or even months on in some environments).

Vaguely relevant: Long ago the then sole national NZ telecom company started using a copper to copper twist join inside a melted PVC outer. In the variable fullness of time this was found to be a fatally bad idea and all such joins had to be re-made. They were then soldered.

• And Kynar wire is great to have around even if you're soldering, for bodge wires or putting SMD ICs onto 100 mil protoboard. – Ignacio Vazquez-Abrams Jun 15 '15 at 1:15

If you're using an automatic cut-strip-wrap bit on the wire-wrap gun, use the Kynar wire. Otherwise it cuts, strips, and wraps, but not necessarily in the correct order! I had trouble with the wrong wire - often there were breaks inside the first (insulated) turn round the pin, so a successful looking joint was actually open circuit.

If you're using the normal (much slower to use) bits, or a hand wire-wrap tool, then either wire is fine.

The wire wrap gun, with the correct bit, correct wire, and practice was probably 20x as fast, maybe more.

The gun I used was the green Gardner-Denver one, (eBay link) only 240V. Nowadays available from Weller (price has gone up a little). As for the bit ... I couldn't get their own Cut/Strip/Wrap bit to work worth a damn. In the end I had to phone a friend at the BBC and beg him to find the right part : from an obscure British manufacturer probably long gone. However the tool looked a bit like a precision-made version of (and worked like) this description.

I can vouch for the gun. I can't remember any longer whether Kynar or Tefzel wire gave the higher success rate. And I can't vouch for the specific bit shown, though it operates on the right principle (you insert the wire at the tool end, and the cutter 1 inch up trims it to length). But I do remember the right tool, wire, and technique gave a huge productivity increase and very low failure rate.

• I am using a hand tool. Can I ask you for model numbers for the wrap gun and cut-strip-wrap bit. How much faster is it vs the hand tool? – mcu Jun 14 '15 at 20:37

You're fine with the cheaper wire. PVC only starts melting around 160C.

• Some source references for the assertion about PVC would improve this as an answer. – David Jun 14 '15 at 20:30
• @David - Since you need it -- "PVC starts to decompose when the temperature reaches 140 °C, with melting temperature starting around 160 °C." from en.wikipedia.org/wiki/Polyvinyl_chloride – Michael Karas Jun 14 '15 at 20:43
• I added that comment in the low quality posts queue. I think the answer is fine, but could be improved with that as an edit. – David Jun 14 '15 at 20:53