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Butt joint soldering repair of a handset cord broken at the cord retainer - tinsel wire splice

Started by TelePlay, July 07, 2018, 06:05:49 PM

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I'm sure others have done something similar or have a better way to do this but this is what I did to get good results. I've had great success at doing butt joints in other hobbies including telephones but this is my first attempt at using that technique to fix a cracked handset cord.

I remember members saying they repair these types of damage but can't remember any techniques being posted so here is my first go at doing this.

The straight handset cord off of a 1955 500 was totally cracked where the cord went into the handset retaining nipple. Yes, easier to just replace the cord but this was a date matching phone/cords so did the tedious fix.

Sorry, no before pictures but imagine the line cord separated from the nipple with the 4 leads showing and most of the insulation gone so the leads were shorted to each other.

Cut the cord at the break. Used an Exacto knife to carefully split the retaining nipple down it's mold seam and removed the 4 leads.

Since the nipple would be replaced about 3" down the cord, I cut off 3" of the spade lug ends and stripped 3" of black cover off of the handset cord.

Stripped 1/4" of insulation off of the ends of the leads. Removed the string leaving only the flexible twisted/tinsel conductors.

Cut a 6" piece of 22 gauge stranded copper wire and stripped off the covering. Pulled the strands apart.

Using one strand, I wrapped it a few time around the one side of the 1/4" tinsel and then laid the stripped end of the piece to be butt jointed over that first wrapping. The used the copper strand to wrap both 1/4" ends together. Went back and forth about 3 or 4 time to tightly cover the overlapping wire ends.

Soldered the wrapped joint, cut off the unused copper wrapping wire and covered the joint with shrink wrap (essential to put the shrink wrap on one side of the wires to be jointed - no way to get the right side on once soldered). Each joint test continuous with about 1 ohm of resistance (and that could be due to the probes making contact with the oxidized spade lugs).

When all 4 were done, reamed out the line cord end of the nipple to get ride of the lead mold canals to make room for the line cord covering. Put about 3/8" of covered cord into the nipple. Separated the rest of the retaining nipple and laid the 4 leads in place. Then, sealed the cut together with water thin cyanoacrylate glue (super glue) starting at the line cord end of the nipple and working my way to the loose wires. Glued about 1/4 to 1/2 inch at a time to make sure the seam joined together. Cures to self holding in about 5 to 10 seconds of holding with fingers. In my opinion, no workshop is complete without a 2 ounce bottle of water thin super glue (eBay order only, not available in local stores).

End result was quite good as long as the cord is put back into the handset with the seam down. Doesn't show that bad but no reason to put that glued side up.

The repaired line cord is only about 3" shorter than it was before the fix, the length of the retaining nipple. And, this fix also retained the original spade lugs. Went back together as it was built.


That was a good idea wrapping copper strands around the tinsel wires. I've tried just soldering to those it worked but I wasn't happy with the results. Too weak a joint.
What did you use to close the incision on the cord?

Very innovative, particularly how you held the two ends of the butt joint together.



Quote from: Key2871 on July 07, 2018, 06:39:22 PM
What did you use to close the incision on the cord?

Water thin super glue

I pour a bit into a plastic medicine dispenser cup and use a fine metal wire to pick up a bit and insert it into the cut. Dipping the wire into the bottle will cause the bottle to turn hard after a few months and using the dispenser tip just does not work. It is water thin so any extra applied to anything will run and can bond fingers to the object.

When you calculate how much per ounce the stuff in a blister pack costs at a local store, you will see that 2 ounces of this stuff at $7 is the deal of the century.

A 4 gram bottle of Loctite superglue is about $6 at Ace Hardware. That's $42 an ounce. The above 2 ounce bottles are $3.50 per ounce with free shipping.

There are several water thin sellers on eBay so the price is always about the same, $7 a bottle with free shipping.


Quote from: on July 07, 2018, 06:43:41 PM
Very innovative, particularly how you held the two ends of the butt joint together.

Thanks. It's not that hard to do. Pinch one end of the thin wrapping wire under the thumb holding the wire, wrap a bit, grab the end of the other piece under that same thumb, wrap the two together, grab the other end of the joint with the other hand and wrap the end that was held under a thumb at first. Do this switch holding/wrapping twice and the joint is ready to be soldered.

Have to use thin copper wire. Anything other than copper won't solder well. The strands of 22 gauge copper stranded wire work well. Along the wire is weak but wrapped about the but joint in several layers makes it strong and the couple of layers are not any thicker than the wire rubber covering so the shrink wrap is smooth.


This is where that idea came from. I've been using butt joint coils to replace capacitors deep inside old radio chassis for years. Sometimes I used them to extend internal phone wiring, it's a clean, tape free extension.

For solid wire, it's a lot easier. Simply create the butt joint coil on a wire gauge just a bit larger than the wires to be joined. Then, put the ends of the to-be-joined wires into the coil and solder. Nice, tight, clean and well flowed solder joint. The solder flows into the coil and grabs the wire inside. I also use a solid 22 or 24 gauge wire to make the coils to have enough strength to hold the two wires to be butt joint in the coil.

With tinsel, the wrapping with thin copper wire cages the tinsel inside the wrap to hold it for soldering and provide a good solder joint. I did no tin the tinsel prior to wrapping, that would be very difficult to do. Just wrap and solder.


Oh, I see you made coils then put the wire lead inside, and soldered. Because I also have use hair fine wire make splices with on tinsel wire. And it's very tedious work, and some times its a weak joint I have to beef up a little.
But that tool you use is great, I have super small drill bits and a bit holder I could use for the same thing. I would just turn the bit around for a smooth surface.


Quote from: Key2871 on July 07, 2018, 08:43:15 PM
Oh, I see you made coils then put the wire lead inside, and soldered. Because I also have use hair fine wire make splices with on tinsel wire. And it's very tedious work, and some times its a weak joint I have to beef up a little.

No, the image with the yellow wire was an example of how it is done on solid wire such as resistors, capacitors and similar components within old radios that have to be replaced.

Handset cord tinsel wires can not and will not work with coiled tubes shown in the solid wire example. The image attached to this reply is a step by step drawing supporting the following textual steps to butt solder two tinsel wires to each other.

1) Hold the thin wrapping copper wire against one of the tinsel wires and wrap the copper wire around the tinsel 6 or so times to give it some substance. This is the hardest step in that the tinsel will want to move with pressure from the wrapping wire. Doesn't have to be wrapped pretty, just tightly.

2) Place the other tinsel wire over the just wrapped tinsel wire and hold the end of this second wire under the thumb against the just wrapped tinsel wire and wrap the copper wire around the tinsel wires now laying on top of each other about 6 times that are not under the thumb.

3) Move the thumb to the second wire so that the left half of the overlap, the part that was under the thumb, can be wrapped with the copper wire tightly about 6 times. It is important that the last lay of wrapping be tight so the solder joint (copper to tinsel) will be good.

4) Solder the wrapped copper wire which will also catch, bond, the tinsel wire wrapped inside the copper wire

5) Trim off the excess copper wrapping wire leaving a solid and smooth butt joint

6) Cover the joint with shrink wrap to protect it and give it additional strength

After the overlapped tinsel wires are wrapped, they will stay together inside the tightly wrapped thin copper wire. This joint can be laid on a bench top for soldering. It will not come apart if handled gently. Once soldered, it is a solid, stiff joint. The key is wrapping the first tinsel to get it strong enough to support some of the second tinsel so it can be held at the far end of the second tinsel to allow the two tinsel wires to be wrapped tightly together on one end. The hand is then moved to that wrapped side so the overlap can be wrapped on the other end. It is far from a weak joint if well and tightly wrapped and soldered completely. The shrink wrap is to keep the tinsel on each end of the solder joint from moving and breaking off of the soldered joint.

As a side note, wrapping tinsel with a fine copper wire and soldering it is a good way to put a spade lug on tinsel. A short piece of shrink wrap covering the crimped spade lug and 1/4 to 3/8" of the tinsel wire cover is a good way to keep the tinsel from breaking off of the spade lug due to movement over time.


Off topic:

As for wrapping solid wire coils, I use whatever I have that is a couple of thousandths of an inch larger in diameter than the solid wire over which it will be slipped. Sometime the new cap wire is smaller or larger than the cut out cap wire meaning I have to wrap one side of the coil with one diameter and the other with a different diameter. I like to leave a small gap between each of the two coil so I can see each of the wires is inserted half way, meet in the middle, before applying solder. I can't even begin to image how difficult it would be to try and insert tinsel into a coiled copper wire, impossible is the word that comes to mind.


John - Great stuff!  This is about as close to surgery as I think I've seen on this forum!  You have equal (large) portions of patience and creativity.  I have seen a couple opportunities to acquire a gray straight 500 handset cord that had been hacked up to use in an F handset.  I passed on those as I wasn't sure how to go about surgically reattaching the cut wires.......



Quote from: RB on July 09, 2018, 10:28:13 AM
Nice technique! very nice. 8)


To be totally accurate, it's not a true "butt" splice (which would be end to end) and it's not a twisted inline splice which is impossible with tinsel wire. It's actually an overlap of ends splice of very flexible stands held together and supported by wrapping fine wire around the overlap. I guess we could call it a "tinsel splice."

However or whatever it's called, the tinsel splice gives the same result as a butt splice in that the final splice that is not larger in diameter than the outer cord covering and it only uses 1/4" of each end to be spliced.

If someone is going to try this, it is best to practice two or three times on junk wire to get the hang of it, so develop good holding and wrapping techniques. Takes less than 5 minutes per splice once the learning curve kicks in.



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It's been a while on this post but I am definitely going to try this next time I have to splice tinsel--tried it for the first time today and wasn't too pleased so I was just searching and found this!


Great thread, thanks for taking the time to document this.

What is the shelf life of this superglue once opened? No matter which brand I purchase or which container, whenever I go back to it the glue has solidified.
Am always careful to remove excess before replacing the cap, and ensure it is tightly on.
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