Can Kapton Tape Be Used Like Electrical Tape?

[Kisatchie]

I've decided to solder my layout feeder wires to the busses. Can I wrap the joints in Kapton tape? Or is there a specific electrical tape I should use? I don't know nuthin' 'bout electricity.


Hmm... I'd put plaster
on 'em...

[Xmtrman]

Kapton is pricey and its most valuable use is where its thinness and puncture strength is critical...Like inside a locomotive's DCC installation.

For buss wires, go get yourself some conventional electrical tape.

By all means help yourself to a good brand name (3M or similar) rubberized tape but it will still be much cheaper than Kapton.

[jagged ben]

Not only will Kapton be too expensive but it will probably not work nearly as well. 

[robert3985]

I've decided to solder my layout feeder wires to the busses. Can I wrap the joints in Kapton tape? Or is there a specific electrical tape I should use? I don't know nuthin' 'bout electricity.


Hmm... I'd put plaster
on 'em...

Since you say you "don't know nuthin' 'bout electricity" I'm gonna give you a detailed opinion...

My experience with soldering wires under layouts, then using either colored electrical tape, paint-on-insulation, or shrink tubing vs using appropriately sized, genuine 3M Scotchlok Insulation Displacement Connectors (IDC's...or "suitcase" connectors") is that the soldered joints often fail, and the 3M Scotchlok IDC's don't. Also, IDC's are exponentially easier and quicker to use, and much less likely to produce a substandard electrical joint.

Insulating solder joints with tape is also a sloppy, ineffective way to do it as it ever-so-slowly loses its adhesive quality and comes unwrapped.  I prefer shrink tubing for soldered joints if possible.

I too thought when wiring up my Ntrak modules way back in the '80's that soldering was the better solution, but over the years, it was always (ALWAYS) the soldered joints which were failing.  Of course, Ntrak modules get broken down, folded up and put in a truck or trailer and transported to shows...where they're unfolded, set up and clamped together...over and over through the years...experiencing a lot of stresses that home layouts probably aren't going to have.

When ripping out my rat's nest of DC wiring on my sectional/modular layout five years ago and replacing it with what I wanted to be "the best" DCC wiring, I did some research into genuine 3M Scotchlok IDC's and found out some interesting facts.  First, they're designed for control circuit wiring, fixture wiring, appliance wiring, signal and PA systems, and automotive/boat/RV wiring. which means they're meant to be neat, robust, quick, and reliable...and they are.  If they weren't, then your automotive joints would all be soldered, not crimped.  Second, the metal used in them is specifically formulated to be oxidation resistant, so contrary to a lot of rumor-mongering, they do not corrode because of their plated brass blade construction.

There are some electrical joints that I still solder...my DC and power routing wiring to and from my Tortoises for example...and the wires attached to my toggle switches.  BUT...and this is a big "BUT"...all of my wire to wire DCC joints (primary 12AWG buses, secondary 14AWG buses, and 22AWG track feeders) are all joined together with the appropriately sized 3M Scotchlok IDC.

All of my continuing references to "genuine 3M Scotchlok IDC connectors" will be just "IDC's"...but I only recommend real 3M products, not Chinese copies.

Using IDC's, joining the wires goes quickly, they're instantly and reliably insulated, the job is consistent and neat, and if you buy your IDC's online in batches of 100 or more, they're cheap.  You can also remove them if necessary and reuse them if you're careful.

In the five (almost six) years since I did my DCC wiring on my layout, I have had ZERO problems with wire connections using genuine 3M Scotchlok IDC's...all of my problems have been with my soldered wire joints (not a lot since I know how to solder, but definitely some) usually from oxidizing because of the flexing from vibration produced when transporting my sectional/modular layout to 3 shows a year.

Photo (1) - Here's a photo of the underside of Echo Yard featuring my DCC wiring and lots of genuine 3M IDC's:



As opposed to a lot of model railroaders, I rarely (almost never) use terminal strips.  The only place I've used them in my layout so far is on my portable DCC electronics board, but not anywhere on my layout's benchwork.  I run 12AWG black/red ultra-high quality speaker zip wire as my primary bus wires (I bought a 300' roll of it on eBay for less than 40 bucks), and then I run separate 14AWG black and red ultra-high-quality speaker wires (not zip wire) as secondary bus wires which run directly under my trackwork and are the only wires attached to my primary 12AWG buses.  Every piece of rail has a 22AWG solid copper feeder in either black or red insulation soldered to the railfoot near the middle of that piece of rail.  I limit these to 6" or less, and they attach directly to either the black or red 14AWG secondary bus wire running directly under my subroadbed.

I drill 1/16" holes positioned between ties on my already-laid ME C55 and hand-laid C40 track, cut a bunch of 22AWG feeders in both red & black insulation, strip about a half inch of insulation off the end that will be place under its respective rail, and flatten about 1/8" with my flat-nose pliers and tin the flat part with solder, then bend it over at 90deg.

I solder my feeders to the underside of my rails, but sometimes I solder them to the sides of the rails or to the top of a PCB tie.  IMPORTANT...check each and every solder joint for electrical continuity, AND if that joint has shorted the two rails.  You DO want continuity between the wire and rail, but you DO NOT want the left & right rails to be electrically connected in any way.  NEVER ASSUME...TEST.

After I've soldered all my feeders to my rails, and thoroughly tested each joint, then I add a drop or two of gap-filling CA to the insulated wire where it exits my subroadbed, and squirt it with Accelerator.  This minimizes accidently pulling the wire off the rail above by pulling it from below.

The rest is easy, just attach the black feeders to 14AWG or 16AWG secondary bus wires using the appropriate IDC by inserting both the "run" wire and the "tap" wire into the IDC, then pressing the metal blade so it cuts the insulation and crimps both the "tap" & "run" wires.  Check the electrical continuity and track above for shorts before folding over the plastic shield and locking it.

The type of IDC you're looking for for 99.5% of you connections is the "Run & Tap" IDC ...which means that it allows a run-through of one wire, and another wire to tap into it.  Different colors means different sized blades on the IDC's to accommodate different sizes of run and tap wires.  I use 3M "brown" Scotchlok 567 IDC's to accommodate 12AWG to 10AWG "run" wire, and a 14AWG to !8AWG "tap" wire...this is to run my 14AWG secondary buses off of my 12AWG primary bus wires.

To accommodate running my 22AWG track feeders off of my 14AWG secondary bus wires, I use 3M "red" Scotchlok 905 IDC's to accommodate 18AWG to 14AWG "run" wire, and a 18AWG to 22AWG "tap" wire.

I did a quick search for prices, and Amazon sells a 100pc bag of the brown IDC's for $18.95, and a 100pc bag of the red IDC's for $12.95...these are genuine 3M Scotchlok IDC's and you might be able to find a better price or free shipping by taking more time to search than I took. Make sure what you buy is the real 3M deal.

If I had it to do over again, from my research about signal loss and wire gauge, I would have gone with smaller 14AWG ultra-high-quality speaker zip wire as my primary power buses, and used 16AWG wire for secondary buses.  This would have changed the color and size of IDC's for splicing the primary and secondary buses, but my red 905's would have remained the same.  When my sectional/modular layout is complete, it will have several scale miles of double-track mainline...so I was looking for what I thought at the time was optimal quality and size of wire.  However, I have not experienced any signal loss problems yet with just over 300 feet of run, so my worries may be more theoretical than practical.  Ntrak uses 12AWG as their standard power bus wire size, and as far as I know, they aren't experiencing signal loss problems in their huge setups due to wire diameter.

If using 3M Scotchlok IDC "run & tap" connectors interests you, here's a link for selecting type and color for you wire sizes:  http://solutions.3m.com/wps/portal/3M/en_US/EMDCI/Home/Products/ProductCatalog/~/3M-Scotchlok-Electrical-Run-and-Tap-Connectors?N=5430181+3294245698&rt=rud

Cheerio!
Bob Gilmore

[nkalanaga]

The big problem with shrink tubing on bus wires is that it has to be threaded on BEFORE the second end of the bus is attached to something.  There's no way to go back later and insulate a new connection.

I agree with Bob that electrical tape doesn't last, but I still use it in a few places, for the same reason tubing doesn't work.  My fix for it failing is strapping/filament tape, the fiber reinforced packing tape.  That stuff will last almost forever, but is NOT made for insulating wires.  Wrap the connection good with electrical tape.  If you have two connections at the same point, such as one in each bus wire, wrap them both, as usual.  Then wrap the entire joint in strapping tape, to hold the electrical tape in place.  Getting it all off, if the joint has to be disconnected, can be a pain, but it won't fail.

[robert3985]

The big problem with shrink tubing on bus wires is that it has to be threaded on BEFORE the second end of the bus is attached to something.  There's no way to go back later and insulate a new connection.

I agree with Bob that electrical tape doesn't last, but I still use it in a few places, for the same reason tubing doesn't work.  My fix for it failing is strapping/filament tape, the fiber reinforced packing tape.  That stuff will last almost forever, but is NOT made for insulating wires.  Wrap the connection good with electrical tape.  If you have two connections at the same point, such as one in each bus wire, wrap them both, as usual.  Then wrap the entire joint in strapping tape, to hold the electrical tape in place.  Getting it all off, if the joint has to be disconnected, can be a pain, but it won't fail.

OR, slip a Scotchlok IDC on the bus run wire, then insert the cut end of the tap wire into the IDC until it stops, squeeze the blade with a pair of channel-locks, test, and fold the integral plastic shield over the blade side and VOILA!!  in about 20 seconds max...you're done. 

Just sayin'.... 

Cheerio!
Bob Gilmore

[Ngineer]

From my experience, Kapton isn't sticky enough.

I always have a hard time when trying to make Kapton stick to loco frames.

Electrical tape adheres better because the glue layer is thicker.

   Javier

[Kisatchie]

Since you say you "don't know nuthin' 'bout electricity" I'm gonna give you a detailed opinion...

My experience with soldering wires under layouts, then using either colored electrical tape, paint-on-insulation, or shrink tubing vs using appropriately sized, genuine 3M Scotchlok Insulation Displacement Connectors (IDC's...or "suitcase" connectors") is that the soldered joints often fail, and the 3M Scotchlok IDC's don't. Also, IDC's are exponentially easier and quicker to use, and much less likely to produce a substandard electrical joint.

Thanks, Bob! You've changed my mind.


Hmm... Kiz really should
change his mind... for a
new one...

[Kisatchie]

Okay, I'm going to use 20 gauge feeders and a 14 or 16 gauge bus, so I found this 3M #314 connector:

https://www.zoro.com/3m-displacement-connector-22-14awg-pk50-314/i/G1908207/?gdffi=047ada998cf641fa93e55ae8579df863&gdfms=0F37BF6737774074AA0225DFDB77F888&gclid=CjwKEAjw3fG4BRDsn9GAv7T2zEkSJACNJdjg2ilAohlUS0h_O1C03snLPbnHSeLlf31J0PqyFHh_xxoCbBzw_wcB&gclsrc=aw.ds

It accepts 22 gauge to 14 gauge wire, and that's the cheapest price I've found. I'm just wondering where the bus wire fits in it. Also, do I need any kind of special tool to crimp the wires in it?


Hmm... a sledge hammer
should work...

[Chris333]

On my last car I installed LED bulbs in the taillights. Since the LED's draw less power you needed to wire in a resistor for the turn signal blinkers to work right. The resistors came with those suitcase connectors that were pre-loaded with dielectric grease.

So every once in a while my lights stopped working and I had to squeeze the suitcase connector to get them working again. It became normal that every time I drove past a large window I would check that my tail lights still worked. After a few years of this I cut all the wires and soldered them, they never failed after that.

I have no idea how they work on indoor use, but I would never use a suitcase connector on a car again. They were great in that I didn't have to cut any factory wires, but they just don't always make good contact.

Just sayin'

EDIT: The exact kit I used with the included connectors:
https://www.superbrightleds.com/moreinfo/flashers-load-resistors/led-light-load-resistor-kit-led-turn-signal-hyper-flash-warning-fix/190/

[garethashenden]

On my last car I installed LED bulbs in the taillights. Since the LED's draw less power you needed to wire in a resistor for the turn signal blinkers to work right. The resistors came with those suitcase connectors that were pre-loaded with dielectric grease.

So every once in a while my lights stopped working and I had to squeeze the suitcase connector to get them working again. It became normal that every time I drove past a large window I would check that my tail lights still worked. After a few years of this I cut all the wires and soldered them, they never failed after that.

I have no idea how they work on indoor use, but I would never use a suitcase connector on a car again. They were great in that I didn't have to cut any factory wires, but they just don't always make good contact.

Just sayin'

EDIT: The exact kit I used with the included connectors:
https://www.superbrightleds.com/moreinfo/flashers-load-resistors/led-light-load-resistor-kit-led-turn-signal-hyper-flash-warning-fix/190/

This has been my experience with suitcase connectors as well. They're easy to install, but they don't hold well long term. I had several that had stopped gripping the wire, so I tightened them and they cut through the bus! 
If you get a dry solder joint that's going to be just as unreliable, but a well done solder joint is preferable in my opinion.

[robert3985]

The secret to using "suitcase connectors" is to buy the properly sized genuine 3M Scotchlok IDC's.  I cannot vouch for any other off-brand China-made counterfeits you might buy at Autozone, The Home Depot or WalMart.

The reason you're having to jiggle the IDC's you bought is that they aren't properly sized for the gauge wire they're going on. 

So, what you have to do when using them for model railroad wiring, is to be sure about the gauge of wire you have, then use the references at the 3M website to find out what the "run" and "tap" sizes are...write down the color and part number and then go online and buy them in bags of 100 pcs. If you find genuine 3M Scotchlok IDC's at your local store, they're gonna cost you at least four to five times as much.

Since I'm using mine for inside use, mine don't have any grease on 'em...and I'm using literally hundreds.  Not a single problem in goin' on six years now.

Also, I used the real-deal 3M connectors in my Suburban when I installed the multi-amped stereo system for various electrical connections in it in 1994 when I bought the beast.  21 years later, it's sounding as good as it did when I put it in.  The only problem I had was the RCA connectors would sometimes work their way out of the head unit.

Okay, I'm going to use 20 gauge feeders and a 14 or 16 gauge bus, so I found this 3M #314 connector:

https://www.zoro.com/3m-displacement-connector-22-14awg-pk50-314/i/G1908207/?gdffi=047ada998cf641fa93e55ae8579df863&gdfms=0F37BF6737774074AA0225DFDB77F888&gclid=CjwKEAjw3fG4BRDsn9GAv7T2zEkSJACNJdjg2ilAohlUS0h_O1C03snLPbnHSeLlf31J0PqyFHh_xxoCbBzw_wcB&gclsrc=aw.ds

It accepts 22 gauge to 14 gauge wire, and that's the cheapest price I've found. I'm just wondering where the bus wire fits in it. Also, do I need any kind of special tool to crimp the wires in it?


Hmm... a sledge hammer
should work...

The bus wire will be the "run" wire, & the feeder will be the "tap" wire.  I use 14AWG stranded wire for my secondary power buses, and 22AWG solid wire for my feeders....soooo....I think you'd use the same 3M RED Scotchlok IDC as I do...which is designed for these gauges of wire: 22 - 18 AWG (Tap), 18 - 14 AWG (Run)
  The part number on my package says "3M905 RED" and the 3M site calls them "905 color RED"...these aren't "fire resistant" which I find unnecessary.

The cheapest I found was at eBay here: http://www.ebay.com/itm/3M-905-RED-Scotch-Loc-Self-Stripping-Auto-Tap-Connector-22g-18g-100pcs/201310389362?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D36461%26meid%3De66c28c810204f4f8241635d929ca868%26pid%3D100033%26rk%3D1%26rkt%3D4%26sd%3D201310389362 

Cheerio!
Bob Gilmore

[Kisatchie]

The bus wire will be the "run" wire, & the feeder will be the "tap" wire.  I use 14AWG stranded wire for my secondary power buses, and 22AWG solid wire for my feeders....soooo....I think you'd use the same 3M RED Scotchlok IDC as I do...which is designed for these gauges of wire: 22 - 18 AWG (Tap), 18 - 14 AWG (Run)
  The part number on my package says "3M905 RED" and the 3M site calls them "905 color RED"...these aren't "fire resistant" which I find unnecessary.

The cheapest I found was at eBay here: http://www.ebay.com/itm/3M-905-RED-Scotch-Loc-Self-Stripping-Auto-Tap-Connector-22g-18g-100pcs/201310389362?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D36461%26meid%3De66c28c810204f4f8241635d929ca868%26pid%3D100033%26rk%3D1%26rkt%3D4%26sd%3D201310389362 

Cheerio!
Bob Gilmore

Thanks again, Bob!


Hmm... those connectors
are cute. I'll have to order
some...

[ednadolski]

What I like about the Scotchloks is how fast they go together, as opposed to soldering.   Makes a big difference when you have a lot of connections  to do, or if access is awkward.   IIRC 3M also sells a special crimping tool, but I use a regular slip-joint pliers.   With larger wires it can take a pretty firm squeeze to make a complete connection.   Overall, I'd never want to go back to soldering or wire nuts.

Ed

[Nato]

           No Kriptonite Tape almost killed Superman alias Clark Kent when he was working on his layout of the Metropolis Central. Do not use this tape, I repeat "Do not use this tape". Nate Goodman (Nato).