Teflon wire

Where do you modders get your teflon wire. It seems to be really hard to find any place. If any of you SF Bay Area modders have a local source that would be even better. Tired of using PVC wire as it shrinks when soldering.

Hi there,

I dont know if this will help, but i've used teflon
tubing quite a bit in the past. It comes in various
diameters you can slip over bare wire if you like.

Take care,
Al

[ QUOTE ]
unnerv said:
Where do you modders get your teflon wire. It seems to be really hard to find any place. If any of you SF Bay Area modders have a local source that would be even better. Tired of using PVC wire as it shrinks when soldering.

[/ QUOTE ]

Halted Specialties - HSC (corner of Central Expressway and Lawrence Expressway in Sunnyvale (<1 mile from my home...) has LOTs of surplus teflon wire - VERY cheap, many sizes/colours... It's in the back corner next to all the other reels of wire.

george.

thanks guys for the quick response. I might have to run down to HSC this weekend since it is only about 40 mins away (I live out by SFO.)

I found some shops on-line that will sell by the foot. Google teflon wire.

Hello there,

Hey that reminds me...

I've been looking for some of that test wire that's
used for test leads and such. It's got a silicone
rubber insulation rather than plastic so it takes
many many flexes without having a problem.
Anyone have any info on where to get this kind
of wire?

TIA

Take care,
Al

[ QUOTE ]
MrAl said:
Hello there,

Hey that reminds me...

I've been looking for some of that test wire that's
used for test leads and such. It's got a silicone
rubber insulation rather than plastic so it takes
many many flexes without having a problem.
Anyone have any info on where to get this kind
of wire?

TIA

Take care,
Al

[/ QUOTE ]

http://www.daburn.com/2636.html

http://www.nyblimp.com/superior/wire.htm

http://www.shopatron.com/product.phtml?product_id=NOV5500&mfg_id=135

It's getting popular with the RC folks:
http://www4.tpg.com.au/users/rikim/info7.htm
http://www.ripmax.com/PriceList/T2200.html
http://www.ripmax.com/

http://www.wsdeans.com/products/wire/

If you need a higher voltage version:
http://www.caton.com/wire.htm


FYI, if you ever need rather flexible wire for actuators or moving items:
P/N 2671/16, 16 ga, 665 strands of 44 guage wire, .015" insulation wall, 300V insulation, .096" overall diameter.

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=257535&Row=44811&Site=US



Teflon wire found here:
http://www.alliedelec.com/catalog/pf.asp?FN=323.pdf

450C (850F) rated wire:
http://www.alliedelec.com/catalog/pf.asp?FN=325.pdf

While teflon wire has it's place, it's also hard to work with, tough to strip well. Most guys will nick strands (unless they have the *special strippers* indended to be used for the purpose), which invites failures later.

Good service can be had from convenitonal insulations, IMO using teflon insulation to counter poor soldering techinques is the wrong way to go. Better to practice soldering using traditional insulations.

Doug Owen

I totally agree with Doug that using teflon is no subsitute for good soldering, but with pvc based wire there is always a little shrinkage. Most of the time regular wire is fine for me. What I am looking for the teflon wire is for those places where you can only have a 1/32 exposed due to close proximity to the heat sink like I did on one of my Surefire E1 SG mods. The post that the lux sits on is only about a 1/16th wider than lux itself. This forced me to have to make my connections come from inside the post and connect to the leads of the lux while having very little clearance between the post, the reflector, and the leads. The wire is only about a 1/32nd above the post where it is soldered. If the pvc insulation had shunk back any further than it did I would have had to scrap the whole thing as the positive would have shorted against the post. Most of the time I get very little shinkage as my soldering skills are pretty decent. I was saving the teflon wire for those challenging situations and just wanted to have some on hand for the next time I ran into one.

BTW George, thans for the tip for HSC. I had never been there before. Very neat place. I wish I had more time to walk the isles to see all the other cool stuff they had, but I was already 45 minutes late getting back to work. I will definately have to stop by there again when I am in that neck of the woods.

I also agree with Doug and unnerv. However, I have been using teflon coated wire exclusively for lead wires to and from the converters, with the exception of the ground wire typically. I do have proper strippers and I would like to think my soldering skills have improved and the MetCal certainly aids in getting the job done! I use tinned stranded wire that has a teflon jacket because I think it's better wire and the jacket seems thinner than other similar gauge wire I have tried. /ubbthreads/images/graemlins/icon3.gif

Hi CPF folks,

Newbie:
Thanks! I'll check those out. Wow, not cheap stuff

Doug:
Well said as usual I hate that stuff. Wire ends up breaking, etc.
That's why i prefer solid wire (when possible) with the teflon tubing
slipped over it for insulation. I've used this for many a protoboard
and it lasts years and years. I've used gauges as light as 24, but
22 is preferred for strength.

Take care,
Al

Yes, I understand (and support) that there are a number of good reasons for using teflon coated wire but so far nobody's hit on the two that caused it's development however, heat resistance (high temperature use) and abrasion resistance.

In the case in point, shrinkback (a large variable IME) can also be a feature. You should know the general length involved and already be stripping short by that amount. You can undercut the lip of the hole with the tip of your exacto knife, sort of score a ring in the side walls first even to give the insulation something to grip as it *swells up* when you tin in place. Otherwise, tinning before and cutting to size afterwards usually controls the insulation well enough. After the initial shrink back, it doesn't move all that much more with repeated reheats.

Worked at professionally with the proper tools teflon works fine in airplane harnesses, it can work well. In general instrument use, not so carefully controlled and inspected, the results are less good. Al is right about the general dependability of the wire, you work long enough in this industry and keep your eyes open and you see way too high a failure *rate* with teflon wire. The common failure is a break at the strip line from a tool induced nick. It's almost sure to get a strand or two (cut open well used connections some time, like connectors with cut and stripped wires and poor strain relief). With teflon, for some reason, it seems to often proceed to failure. That is, you notice that 'way too many of these failures I've seen are teflon wire'.

Al's also right about using teflon *tube* and buss wire. In the case in point, it would have solved the issue very well most likely. This way you control both the teflon insulation and the conductor with no stripping involved. No nicks. As long as we're talking out of class, here's how:

First, *stretch* your wire. Clamp one end of a few foot (up to 6) long piece in your bench vice (or otherwise secure it). Grab the far end with pliers, pull it tight, then slowly pull just a bit more until you feel it yield and stretch an inch or so. Slowly relax and catch the wire as it starts to sag with your other hand. Cut it into shorter lengths (say 8 or 10 inches) and you have perfectly straight wire to work with. The trick to having enough hands is to use your cutters as the pliers to stretch it with (they're "side cutting pliers" after all....), clamp down a bit, roll the wire around the head of the cutters and hold it in place with your thumb. Then pull the cutter head straight back with your other hand without clamping down any harder on the cutter handles. Now you've got the cutters in your hand, ready to go. Keep some tension on the wire, move your free hand to a few inches from the cutters, hold the wire, cut the first inch off and discard. Now cut the wire off from the vice, say 3 feet worth. Holding tension, make the cut and let the cut end swing down so you end up holding it vertically at the top, the vice end will sag down to toward the floor without much damage. Hold the vertical wire over the workbench an inch or two, cut off say 8 inches, lower it, cut again and so on. The do the same for the piece still in the vice (cut it off an inch or so from the vice jaws and let it hang).

Now slip a piece of tube over the wire that's longer than you need. Working from one end, dress and terminate the wire then slip the tube to the proper position. Dress the remainder of the run. Go to where you're going to end the tube and grab it with your cutters but *do not* cut it, just grab it. Now slide the tube (with the cutters still gripping it) up the wire to where the end of the wire will be and cut *both* tube and wire together. Slide the tube back down the wire to the proper place and everything's perfect length and there's no chances of a nick anywhere. You can then take the cut off wire and tube, slide the tube down a bit and go on to the next connection.

FWIW, in the case in point (having to bring a lead up *iniside* a tight post), I'd have tried to find another solution that didn't involve drilling into the heat path. Maybe a strip of copper foil tape up the side of the post (insulated with mylar tape under it)?

Doug Owen

It can be extermely frustrating to use it without a thermal stripper. With one, I think it's a joy. And I really like the look and feel of the stuff and the fact that you can apply as much heat as you need to get total solder flow up into all the strands with no fear of meltback. The mil spec stuff is typically silver-plated, too so it really solders easily.

Also, its low dielectric constant will result in a higher velocity of propagation, so your flashlight will turn on quicker. /ubbthreads/images/graemlins/wink.gif

It's common on eBay and there's quite a few listings for it now.

Interesting, I used to make military aircraft harnesses, and never saw any teflon wire failures over a 12 year period. But I spent a month or so at school specifically for this, so maybe I pay more attention to this, and the application is a bit more high end. I do remember the PVC wire that used to shrink back badly and also melt. Never had that issue with either one, as we had to use thermal clips during soldering to assure the solder did not wick to the edge of the insulation, which creates localized stress under vibration, inviting early failure. And most of our connectors had to be potted.

We utilized thermal strippers on the teflon wire, but we had a exhaust to pull the fumes out. Otherwise the gasses are really nasty, and if you start to get a headache, you are getting polymer fever, which means you screwed up and better go to the doctor. You can reduce this by setting the thermal strippers just to the point at where the insulation starts to melt. But you still should use forced ventilation.