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Stripping Teflon insulated wire ("Tefzel") ???
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Author Stripping Teflon insulated wire ("Tefzel") ???
Rex Coil 7
I've used Teflon (aka PTFE) insulated wire in the past, and it's always been a friggin punk-ass bitch to cooperate with stripping the insulation. Y'know ... you just sortof deal with it, right?

However, recently I have undertaken the task of making my own module power cables using 20ga "mil spec" PTFE insulated wiring. I want to do a super neat job with this project, so I'd like to be able to get nice clean strips.

An issue when using mil spec wiring (otherwise known as "aircraft wire") is the strand count. Many types of hook up wire usually have only about 7 or so strands wound together to make up the wire gauge. That makes the strands larger (and more durable when it comes to stripping the insulation).

Aircraft wire uses 19 (nineteen) strands to make up the proper gauge, in this case it's 20ga. Since the strand count is higher than non-spec wiring, the strands are far smaller. For instance, 19 strand 20ga uses 19 strands of 32ga wires wound together to create 20 gauge.

32 gauge strands!

I know that some folks (eg; Graham Hinton) use 32 strand wiring sometimes, with great success. Not 32 gauge ... 32 strand 32 gauge wiring. (This is known as "32/0.2" in the UK .... 32 strands of 0.2mm strands ... 0.2mm is 32 gauge).

Aircraft engineers want to save every single gram of weight in every single application. When running dozens ... hundreds ... of wires in large trunk lines down the wings or down the length of the fuselage saving a few thousandths of an inch per wire adds up to a far smaller overall diameter trunk that traverses long lengths of the airframe. Space, as well as weight, are saved. Less weight devoted to wiring may be used as fuel, or cargo, or both.

Anyway.....

So, if a regular wire stripper is used, the chances of tearing or nicking any of the strands are quite high. Especially since Teflon insulation is really REALLY tough stuff, and many times you wither end up using more physical force to sortof ~rip~ that last bit of insulation free, or the strippers are more or less twisted and ~worked~ until the insulation strips free from the wire.

Usually several strands become either cut or broken in the process.

SOLUTIONS?

I've read/heard of heat-strippers used to strip Teflon/Tefzel insulated wiring, but the only heat strippers I can locate are very old used ones on eBay that look as though they've been through a gang fight.

Has anyone used any other solutions for this issue? I had considered trying to modify a soldering pen tip into a sortof hot-knife, but have not tried that yet.

Just to get it said, I use fairly high quality manual wire strippers with pretty sharp cutting edges on the strip holes. They're not your typical imported junk that go dull after a dozen wires stripped. And those "automatic strippers" are horrid devices, all they do is rip and tear the insulation, long with any number of strands. That said, I still have a hard time performing strips without having to cut off the bad strip and try again .... and again ... and again. (ugh!).

I've tried using a razor blade as well, but those 32 gauge strands cut very easily, by the time enough force to cut through the Tefzel is applied I usually end up taking several strands with the insulation.



ANY HELP FROM SUCCESSFUL MEMBERS?


Dead Banana
Dead Banana
Dead Banana

Here's an example of my very first Euro power cable, using 22ga PVC insulated wire. The PVC insulation is ~fatter~ and 22ga is the outside limit on what will fit inside of the ten-pin/two row housings. I only just got the 22ga PVC wire to work on this:



Teflon wiring has a smaller outer diameter for the same gauge as PVC ... so much so that 20ga Teflon (MilSpec 19 strand) has a smaller outside diameter than 22ga PVC! Not a typo there.... I'll repeat that .... 20ga Milspec is smaller outside than 22ga PVC. Allows you to use larger conductors.

Ok, yet another 10k post of mine.

Thanks.
Rex Coil 7
Well, after a bit of sniffin around I can see that the idea of using a modified soldering pen tip to hot-strip Teflon wire insulation is a poor idea indeed.

Man, I really don't like the idea of spending the big billies on a hot stripper (uh ... that sounds .... um .... nevermind). A hot WIRE stripper .... hot WIRE ... tool for removing the Teflon insulation from electrical wire that uses a heat to burn the insulation from the wire ..... holy crap ... no matter how hard I try it just sounds ... well .... haahaa!

~Ahem~ .... SO Any-old-how ..... yea. geez ....

Some days you're the windshield ... other days you're the bug.
Rex Coil 7
PRECISE ADJUSTMENT OF THE TOOL:

So doing some more research, it seems to be all about precision. That said, selecting one of the wire strippers on hand I began filing the closure stops down with a fine file, just a stroke or two at a time. Attempt to strip, check my efforts using a 10x loupe in a bright light, and taking off a few thousandths more off of the closure stop tabs on the jaws of the strippers.

I kept this up until I saw ~roughly~ 90% success (getting a clean strip without cutting in to any of the strands). A bit more v.e.r.y. careful file strokes ... one at a time ... and I think I may have precisely adjusted a set of my highest quality wire strippers to reliably strip 20 gauge MilSpec 19 strand Tefzel insulated wire without damaging the wire strands .. at all!

There's not much room for error. The twisted strands measure anywhere from 0.036" to 0.038" as a group. While the insulation measures at anywhere from 0.057" to 0.059" outer diameter. So there's only about "ten thou" wall thickness to work with until the FAIL point is hit. As it is, the modified strippers are only cutting through about 0.008" of the 0.010" wall thickness, leaving only 0.002" room for the neon FAIL LIGHT to come on.

Careful, patient, deliberate workmanship is demanded. It's ok, making module power cables isn't something to be taken lightly anyhow. Think of the cost of the device in question! A module is worth my extra attention and time. It's why I've taken to making my own power cables in the first place.

At least those are my own feelings on the issue. I know others couldn't be bothered. Bring on the ribbon cables!

Meh ... seriously, i just don't get it ... I hope other folks may gain something of value from this thread.

I have, and I'm the only one saying anything!

Ain't that a bitch!

HAAHAAHAAHAA!!!!
groove
Rex Coil 7 wrote:
PRECISE ADJUSTMENT OF THE TOOL:

So doing some more research, it seems to be all about precision. That said, selecting one of the wire strippers on hand I began filing the closure stops down with a fine file


I would have suggested the hot wire approach. I had one tucked away in Amazon that was around $80 but could never justify pulling the trigger. What wire strippers did you modify?
Rex Coil 7
groove wrote:
Rex Coil 7 wrote:
PRECISE ADJUSTMENT OF THE TOOL:

So doing some more research, it seems to be all about precision. That said, selecting one of the wire strippers on hand I began filing the closure stops down with a fine file


I would have suggested the hot wire approach. I had one tucked away in Amazon that was around $80 but could never justify pulling the trigger. What wire strippers did you modify?
A particularly good Klein #1010. I have 4 Klein 1010 strippers, this one is my best one.

I say "best" ... I'm only referring to the 16 and 18ga holes. It has a particularly sharp set of cutting edges in those two holes.

There's a "stop" that prevents the jaws from closing past a certain point. I just filed that stop down until I got the desired results. I probably removed no more than 0.005", maybe 0.006" ... no more.

My other three sets of #1010 don't have the same edge, probably Monday or Friday production runs.

The hot wire setup is easily the best way (just do NOT breathe that shit ... the smoke ... it's very bad for human consumption). However, to be honest, I've been doing quite well with my "tuned" 1010s. Fortunately, for the work I'm doing with them, I only need to strip about 0.125" off of the end of the wire. My guess is if I had to strip more off I'd be having less success with the manual strippers. I don't know how long these 1010s will hold their edge stripping so much Teflon insulation though. I suppose I'm about to find out!

I just take my time, and patiently carve a circular cut around the insulation, turning the wire inside of the fully closed (tuned!) cutter. Handle pressure is also critical, just enough pressure to close the jaws around the wire and fully bottom out on the jaw stops. After cutting a nice clean circle, I then open the cutters, remove the wire, and grab the cut with my fingernails and pull off the waste (it comes right off, no fighting it at all). I do not use the strippers to pull off the waste end, that seems to be the part of the operation that causes the most failures. That's also when the tool is usually most tightly closed, since you're holding the handles rather tightly to pull the insulation off of the wire at that point. So I have eliminated that part of the process by using my fingernails to pull the waste trim off. When the tool sortof ~rips~ across the wires as it pulls the insulation from the wire, that's when the cutting edges seem to grab hold of the strands and tear them off, or nick them.

I'm sortof mimicking what a set of fiber optic strippers do mechanically, but using my fingernails instead of a metal tool. I used to have a set of Micro Electronics "Micro Strips" (MS1-10-FS) which are made for stripping fiber optic lines. So I'm just mimicking how those work with my hands. Now that I mention it, if I still had my entire MS1 kit I'd bet I could probably work out the proper guide tube and cutter combo to make it work for this Milspec wire. Hmmmm ..... I wonder if eBay is open this time of day?

lol lol

It's slower than rippin' ass through 3 feet of 24ga hookup wire when building a guitar pedal. But I'm not building a guitar pedal, I'm attempting to build a $10k synthesizer that will outlive me. So yes, this is slow, but I only have to do it once (make these power cables, that is). And I'm not being paid by the piece/hour, so it's ok that stripping each wire takes 20 seconds instead of 2 seconds.

smile
Jarno
Watch out with the fumes given off when burning or melting teflon, Fluor fumes are not healthy!
Rex Coil 7
Jarno wrote:
Watch out with the fumes given off when burning or melting teflon, Fluor fumes are not healthy!


Rex Coil 7 wrote:
.....The hot wire setup is easily the best way (just do NOT breathe that shit ... the smoke ... it's very bad for human consumption).....



Yup!
Altitude909
I've switched to these, the scissor type strippers are gathering dust:

https://www.amazon.com/Jonard-ST-550-Adjustable-Precision-Thickness/dp  /B007A1Y986/ref=sr_1_2?ie=UTF8&qid=1509451187&sr=8-2&keywords=jonard+ wire

Hot wire with PTFE is a bad idea, it's super high temperature material to begin with and hot wire strippers are designed for materials that melt at half the temp teflon does. A good mechanical one will work better. And yes, I use teflon coated wire all the time.
Graham Hinton
The only tool I found that worked well for PTFE insulation was the one at the top:



It's called a Stripmaster and is made by Ideal Ind Inc. For manually stripping PVC insulation I use the tool at the bottom. It's all about precision and that is what distinguishes a quality tool from a cheap knockoff. PTFE requires more precision than PVC, if the die is only slightly too large it stretches the insulation instead of cutting it.

For most of the power cables I make now I use a pneumatic stripper (no, not what you're thinking). They are a bit fiddly to set up, but once they are adjusted they can do a bundle of ten wires at a time.
Rex Coil 7
I've learned a great deal by now! This is a GOOD thing!

At this point, best I can tell, it's a hit and miss issue.

Graham has found a tool that ... probably quite by chance alone ... was made *just right* to deal with PTFE insulated wires. I have ... factually ... a flippin box of those auto-strippers of different makes and models. Some are cheap ass crap, but yet still work pretty well for some wires. Others are well made craftsmen's tools (not the brand "Craftsman") that are so damned fickle they're best used as door stops or paper weights.

(Meandering War Story warning: ... move on if you wish: I completely wore out one of them auto-strippers on one single job, it was a 25 year old auxiliary power generator that the customer had purchased at a military surplus auction. The 250KW generator was used to power water sprinkler systems that irrigated small saplings grown and sold by this customer to produce farmers in this area. It had hundreds of 24ga and 28ga control wires, all terminated with 32 and 48 terminal Amphenol weather tight connectors. It was a complete mess, since it had been field repaired by numerous Army technicians over the years using improvised solutions that bypassed many safety functions, just to keep it running. I spent roughly two weeks almost living inside of that friggin thing while I rewired the entire works. I used a small 1k watt generator to power my soldering gear. Haahaa ... "good old days" .... er something of that sort. I didn't mind in the end, at $105 per hour I was fairly compensated for my efforts. That was in 1997, that generator is still in service. BS story complete, returning to topic now.)

On the other hand, I have found a tool that ... again, probably quite by chance alone ... was made *just right* for my situation, that I slightly modified to meet tolerances my situation demands. For now.

In both instances, when the blades wear dull, and the pivot points wear somewhat (or in Graham's case the the mechanicals of the auto stripper wear beyond usable tolerances) both tools will be relegated to PVC wire stripping chores. Since Graham has a high-falootin' mass producin' pneumatic stripper (quite necessary for his situation, without any doubt) his old auto strippers will probably see very little use these days, and they'll probably outlive him.

It has to do with how well the cutting edges were done at the time of manufacture, or how well or poorly the diameter of the stripping holes was made (either in or out of spec). "Spec" is an irrelevant issue, it doesn't matter if the holes passed QC, what matters is how well they fit the wire that's being used at the time. Since PTFE wire (even MilSpec) has a +/- tolerance from run to run, what worked with one spool may not work as well on the next spool. It *should work between runs and batches ... but reality has little to do with expectations.

This issue has had me thinking about making an adjustable feature that would be mounted on the handles of the strippers. Think of a threaded block mounted (riveted?) at the far end of one handle, and an anvil block on the other handle. The idea being making an adjustable jaw stop, that would restrict how far the jaws close in a fairly finely adjusted manner.

Turn the adjustment thumb screw until the jaws close to that *just right* amount, then lock the thumbscrew into place with a jam nut. The thumbscrew would bottom out on some small "anvil" (for lack of a better term), limiting how far the cutting edges close down around the wire. Fine threads on the thumbscrew would provide fairly fine adjustment limitation on the cutting edges, thereby customizing the tool to fit whatever batch of PTFE you happen to have purchased. The stock jaw stops would have to be filed nearly all the way off so as not to interfere with the adjustable feature.

I've basically done just that by filing down the jaw stop until the cutters are in the just right position to deal with the particular batch of 20 gauge Mil spec wire I happen to have rec'd from my vendor.

So far, I'm seeing ~roughly~ 98% success rate with the tool and wire I am currently using. To be honest, I have not seen a single failure yet since I modified the tool. I said "98%" because I haven't done 100 strips so far, and I'm guestimating that I'll fuddup at least two of them by the time I hit 100 strips.

As the cutting edges wear, I may be able to file off another 0.001" or so to compensate until the tool becomes unserviceable due to edge wear, and pivot wear.

I've honed the process down a bit, I use the 18ga hole for cutting the insulation around the wire, then the 16 ga hole to pull the waste free. The 16ga hole is just large enough to grip only the edge if the cut I made with the other hole (replacing what I was doing with my fingernails at first). My bet is that neither of those holes is actually anything near what they're marked as, they just happen to fit my process.

So back to my original statement in this post ..... it's a matter of hit and miss. That said, I can probably modify one of the other Klein 1010s to fit the process now that I know WTF I'm doing with them.
Midiot
I've used Teflon jacket, silver-plated copper wire for quite a while now.
Solid core, and stranded wires.

I find the Teflon quite easy to strip.

I use two common tools at once.....

A manual pliers-type stripper ( http://www.amazon.com/Ideal-45-416-T-Stripper-Stripper-Stranded/dp/B00 0B632YO )
...and long needle-nose pliers.

Let's see if I can describe how, without pics....

I insert the wire in the correct size stripper hole, then clamp it down (to slice the jacket).
Then I clamp the needle-nose to the keeper-side of the jacketed wire, immediately adjacent to the stripper tool.. so the two tools are actually touching, at opposite X angles.

With a very slight "pry" of the needle-nose against the stripper (like a fulcrum), and I can hear/feel a "pop".
The jacket is cut, leaving a small gap. Then I pull the unwanted jacket off by hand, helped by my thumb nail.

Less than two seconds.....and it becomes automatic after some practice.

(lol, I said, "stripper hole" )

It's true, some mil-spec wire does not quite conform to standard AWG sizes, but using this method, you have complete control over the pressure needed to snap the Teflon jacket away without damaging the wire.
imcmahon
Like Mr. Hinton said, the Ideal Stripmaster style is the only suitable tool for tefzel.

I'm an aircraft mechanic, and that's the proper mil-spec tool for it!
Rex Coil 7
Midiot wrote:
.... but using this method, you have complete control over the pressure needed to snap the Teflon jacket away without damaging the wire.
I've been stripping wire using that same technique for decades. Yes, it works well on most wires.

However the problem with using that technique (the "needle nose as a pry axis to sortof twist the stripper away from the wire against the side of the needle nose" trick) is brutal on 19 strand wire. The wires are so small that they tend to break (or nik) at the fulcrum.

And even if you use that method, if the hole size of the stripper isn't *just so* you'll still end up just tearing away at the Teflon insulation, no matter how it is you pull the strippers away from the wire.

I broke down and bought a Micro Strip, and a pair of 0.037" blades, I just need to pick up the proper sized guide tube to complete the ensemble. It may work out better than my modified wire strippers.
Midiot
I have a Stripmaster, and found it handy, but sometimes unreliable for slippery Teflon.

I've found my method always reliable, as my hands adjust to the exact pressure needed for any wire.

If you use the same wire (spools) all the time, and the Stripmaster works for all your wire.... then that is the tool.
I get my PTFE wire from mil surplus outlets, and some of it doesn't behave in that tool, so I've been accustomed to skipping it altogether (and it's a bit bulky on a small workbench).
That's just my experience.

Quote:
However the problem with using that technique (the "needle nose as a pry axis to sortof twist the stripper away from the wire against the side of the needle nose" trick) is brutal on 19 strand wire. The wires are so small that they tend to break (or nik) at the fulcrum.

I can agree, if you are not careful. All I really need is enough pressure to slice the jacket 80%, and the twist/fulcrum pops the jacket, then I stop the fulcrum.
But I've also had thin strands fly off the double-action Stripmaster, particularly with loosely-wound stranded wire.
Rex Coil 7
Midiot wrote:
... I've found my method always reliable, as my hands adjust to the exact pressure needed for any wire. ...
Even with wire gauges that are not a good fit for your strippers? And never break a strand (not 7 strand, but 19 strand which uses nineteen 30 gauge strands to create 20 gauge wire)?

You are a talented person. thumbs up Good for you! applause

I'm not as good as that even though I am experience-heavy. I owned and operated a factory authorized repair center for nearly twenty years, then took another ten years building over 500 custom audio processors one at a time, all flying lead construction (untold football fields of wire used, stripped/soldered wire terminations somewhere in the tens of thousands).

So I guess you're really good at it and I'm really bad at it.

Or perhaps it's something else altogether.

Thanks for the advice, I'm sure anyone reading this stuff will come away with new answers to old questions. I'm glad that ages old technique is "always reliable" for you ... keep it up!
Midiot
It's not that you are "bad" at it...., it's just that I might be set in my ways, LOL

It's good to know all methods. If one way is not working, it's good to know a back-up.
Jarno
Given this a little bit of thought, and I think that optical fiber is often also in a teflon sheath, and we used to thermal strip those as well. Can't recall the brand of the tools that we used (also for cleaving and splicing fiber).
But Rex, since you are in the US, this might work as well:
Teledyne Stripall
Been eyeing them for a while, but I really need one for little money, and EU based, seems like just the ticket for stripping ribbon.
Rex Coil 7
Jarno wrote:
Given this a little bit of thought, and I think that optical fiber is often also in a teflon sheath, and we used to thermal strip those as well. Can't recall the brand of the tools that we used (also for cleaving and splicing fiber).
But Rex, since you are in the US, this might work as well:
Teledyne Stripall
Been eyeing them for a while, but I really need one for little money, and EU based, seems like just the ticket for stripping ribbon.
Actually, the "Micro Strippers" were designed for fiber optic cabling. They use a specifically sized cutter that is sold by size down to the thousandths of an inch, and also use a very specific "guide tube" that is also very precise.

Somewhere along the path someone tried using them with teflon, and they worked!

I'll give those TC-1 Stripall units a look see. Thanks for taking the time to round them up!

EDIT: Ok, took a look at the TC-1 .... that's a thermal stripper, not suggested for Teflon insulation due to the health hazards that a few other posters have pointed out here in this thread. They may work for ribbon ... but I'm one of those that believes ribbon cables have no business being in a modular synth. Ribbon cables only have 30 gauge wires ... 30 gauge! I prefer using 20 gauge/19 strand wiring if I can get away with it .... 22 gauge at minimum for power cables.
E.A.S.
Graham Hinton wrote:
The only tool I found that worked well for PTFE insulation was the one at the top:



It's called a Stripmaster and is made by Ideal Ind Inc. For manually stripping PVC insulation I use the tool at the bottom. It's all about precision and that is what distinguishes a quality tool from a cheap knockoff. PTFE requires more precision than PVC, if the die is only slightly too large it stretches the insulation instead of cutting it.

For most of the power cables I make now I use a pneumatic stripper (no, not what you're thinking). They are a bit fiddly to set up, but once they are adjusted they can do a bundle of ten wires at a time.


This.

The Stripmaster is all I use anymore. They're, by far, the best i've used! I have multiple sets each with a different die set, for different ranges.

-M
Markat
What advantages would aircraft wire have in a modular system? I have some I bought a while ago and never really used as it’s quite thick and rigid. Seems like it might be overkill for running 12V less than a foot.
Midiot
Markat wrote:
What advantages would aircraft wire have in a modular system? I have some I bought a while ago and never really used as it’s quite thick and rigid. Seems like it might be overkill for running 12V less than a foot.


Why I like it.... most of it is tightly wound, and much of it is silver plated copper. The teflon jacket doesn't melt away, when soldering.
Most of it is not for flexibility, it's meant for wrapping and bundling and staying stationary.
I use it a lot for connecting "point-to-point" circuits on DIY projects.

For more flexible wire of runs longer than 6", I use thin shielded pairs, such as Canare L2B2AT-200M (24 ga).... or Canare DA202AT-200.
...and if it's for signal connections, I'll ground the shielding at least one end.

For longer "audio" runs, any decent microphone cable and it's flexible.
DC power cabling doesn't really need shielding for short runs.

This is my knowledge....I'm sure others have fav. choices.
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