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Over the years I've used lots of different electrical tapes, cheap and not-so-cheap. One thing they've all had in common is that, while pretty tacky to the touch, it never sticks very well to anything but itself.

Just this afternoon I've been using some 3M Temflex to wrap some inline splice joints in some 0.4mm wire (26 AWG) and am once again frustrated by this issue that results in nice little tape sleeves where the tape sticks to itself (for a time) but not to the wire, thus the sleeves slide up and down the wires they are supposed to cover with very little encouragement..

Are electrical tapes just crap in this aspect? Or is there a particular reason for this?

(Tagged as adhesives because there is no tape tag)

Toby
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    I would say it's about the specific brand quality... – Eugene Sh. May 12 '17 at 14:52
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    They do vary enormously by brand, and cheap ones are often useless. – Simon B May 12 '17 at 14:53
  • I find it to stick very well to any cables insulation, I wonder if it was designed exactly for that... – PlasmaHH May 12 '17 at 14:53
  • I'd guess it's hard to make glue that sticks to anything and can withstand heat at the same time. Wiring must survive mild overheating for prolonged times - electrical codes often require this. – sharptooth May 12 '17 at 15:00
  • I had thought 3M would be a brand that would have at least some knowledge on tapes? Can you suggest a price range you would consider would indicate quality in such tape? I think the one I am using ATM is about €2.10 – Toby May 12 '17 at 15:00
  • FYI, as far as I can tell it's doesn't really stick to the wire *or* the insulation that well - though it is very tacky to touch, and leaves stickiness on everything - kind of counter-intuitive that the tape is sticky yet doesn't stick to anything. – Toby May 12 '17 at 15:01
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    You may be using the wrong tool for the job. Inline splices of thin low-voltage wiring may be a lot cleaner with heat shrink tubing. Incidentally, that is very cheap if you buy meter long pieces in a few desired sizes - the assortments often give you a lot of what you don't need. Or avoid the splice altogether by learning to reliably crimp the connectors you need to an uninterrupted piece of wire. – Chris Stratton May 12 '17 at 15:03
  • That sounds like the cheap stuff to me. I've used electrical tape that sticks well to itself, for years if left alone. – Dampmaskin May 12 '17 at 15:04
  • @ChrisStratton The splices were inline, as in attaching wire A onto a continuous run of wire B - no way to get heatshrink on. – Toby May 12 '17 at 15:04
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    I think they are crap, but it was possibly designed to be removed easily. Try to stretch it, or switch to a better tape. Poliamide is expensive and higher V rating used in transformers. I prefer Heatshrink or in a squeeze, Tuck tape only avail. in Canada which is used for holding panels together and has an insulation rating of at least 10kV/mm thickness, – Tony Stewart EE75 May 12 '17 at 15:05
  • How could a tape sleeve slide on a T joint if you wrapped the tape around and between all legs of the T? – Chris Stratton May 12 '17 at 15:05
  • it unravels easily. solder a Y joint so heat shrink can be used instead of a T joint. Sometimes I have used Polyurethane glob to insulate and others liquid rubber. – Tony Stewart EE75 May 12 '17 at 15:07
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    http://multimedia.3m.com/mws/media/54748O/electrical-tape-wrapping-tips.html – Bruce Abbott May 12 '17 at 15:12
  • People who use electrical tape for this kind of stuff should be sentenced to servicing it 5 years in the future. – Scott Seidman May 12 '17 at 15:19
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    @ScottSeidman Hopefully this harness wont be in use for more than a week or so of prototype testing... but it would be nice if it did actually hold together for that week. – Toby May 12 '17 at 15:35
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    Is your wire polyethelene (PE) or Teflon (PTFE) insulation? Nothing sticks to that stuff- suggest heat shrink with adhesive inner coating. – Spehro Pefhany May 12 '17 at 15:55
  • The preferred NASA method is solder parallel not a T joint and use heat shrink as I recall from my Aerospace days in the '70's. The Electronic Production manager at Magellan (Bristol Aero) taught NASA soldering from a bible about 3" thick. Also the wire twist is the mechanical bond and don't rely on solder for mechanical strength. Always have strain relief with 2~4 Diam to prevent stranded wire fatigue if vibration is possible. Restrain with dental floss like waxed nylon to prevent vibration (Aircraft wire bundle methods) (poor man's choice) – Tony Stewart EE75 May 12 '17 at 15:12
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    It will always be crap when you use the wrong adhesive for the job at hand. It sticks to itself well because it's intended use requires it to stick to itself. – Misunderstood May 12 '17 at 18:22

1 Answers1

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Adhesives aren't universal. The surface energy of the wire insulation will make a big difference to (a) the quality of the bond for a given adhesive, and (b) the nature of the best adhesive to use. As Spehro Pefhany mentions, polyethylene and PTFE are particular difficult for many adhesives to adhere to.

If your wires are PTFE and you have to use that particular tape (one with a silicone or acrylic adhesive might be better) and you can't just use heatshrink, you might get better results by scuffing the insulation surface with sandpaper and/or wiping it with acetone before taping it up. You could also try heating it with a hot air gun before or after wrapping with tape; this may help the rubber-resin adhesive on the Temflex to thermoset.

pericynthion
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    The surface energy aspect is significant. Corona treatment is used in industrial processes to improve initial tack. The adhesive bond can take up to 24 hours to really grab. – Transistor Feb 25 '18 at 09:42