Best Way to Repair Wire Fray by Strainer with Outside Sleeve Ground

[Janglers]

Hi, I have a small electronics wire that I believe is shielded with copper. The strainer where it wire enters is frayed (see photo below), and I can see the copper. The strainer is molded into the cord. I was wondering what would be the best way to fix and strengthen it. I was thinking of just using liquid tape to seal it, but then started thinking it would still be weak. This is on an electronic toy guitar, so its going to get flexed.

Also just out of curiosity, wondering if at the end of the wire (see 2nd photo by screw driver tip), that copper I can see by the strainer is that black taped wire at the inside pcb board. Also show are 4 wires (Red White Green Black)

This is the other end of the wire, inside the guitar.

 

[rjenkinsgb]

Possibly some high-shrink (4:1) adhesive lined heatshrink tube, if the connector at one end is small enough to go through that. It will massively reinforce the cable at the weak point and provide a longer strain relief. I've used that on laptop power connectors that have started to fail in a similar way.

Another temporary repair option that can work well is to build up some self-amalgamating tape over both the strain relief and first two or three inches of the cable, building it up to make a larger and longer tapered relief. It forms one solid mass of rubber over a few hours and stays flexible.

This is my favourite type:

AT7 | Advance Tapes Black Self Amalgamating Tape 19mm x 10m | RS

uk.rs-online.com

(Stretch it well as you apply it & build up several layers to fill the "step" at the end of the moulded relief and give a smooth taper).


The ultimate answer is to replace the cable. It's four core screened, with braid screen wires twisted together and in some small heatshrink, from what I can see in the photos.

It is sometimes possible to separate those moulded on strain reliefs from the cable outer by working a jewellers screwdriver in between them & working around the cable.

A longer, more flexible strain relief will work better. The short moulded ones still mostly cause the cable to bend at the end of the relief, rather than spreading the bending over some distance.

 

[Tony Stewart]

This is one design like so many others that fail to protect wires from broken insulation and broken wires.

It's not they did not use the right material, but rather the wrong design for the material of the plastic shroud. Here they made it very flexible with ribs but then had an abrupt stop at twice the cable diameter with more than twice the stiffness.

The criteria I use is that the strain relief must create a bigger bend radius than the cable (stiffer) yet taper down to almost the same diameter as the cable. This taper length needs to be at least 5 times the cable diameter. The plastic needs to be durable with high adhesion to the jacket. There is a rubber-like dip chemical that is fairly flexible and needs to be thick but looks great with a gloss black.

I prefer a polyurethane coating but it doesn't look as nice, at least nicer than frayed wires. It is sold in lumber stores for sub-floor adhesives in big tubes. I preferred the old voltatile stuff as it cured fast unlike the modern non-volatile that takes 1 to 3 days.

Whatever you use, the thickness and taper depend on the stiffness, so the result is always a larger bend radius at the joint when pulling the wire to the side without an abrupt transition in stiffness.

 

[ahsrabrifat]

Choose a heat-shrink tube slightly larger than the wire diameter. Slide it over the damaged area. Use a heat gun or lighter (carefully) to shrink it. This provides a strong reinforcement and helps prevent further fraying.

 

[Tony Stewart]

Choose a heat-shrink tube slightly larger than the wire diameter. Slide it over the damaged area. Use a heat gun or lighter (carefully) to shrink it. This provides a strong reinforcement and helps prevent further fraying.

That only works if you have a cut wire end.

 

[MrAl]

Hi, I have a small electronics wire that I believe is shielded with copper. The strainer where it wire enters is frayed (see photo below), and I can see the copper. The strainer is molded into the cord. I was wondering what would be the best way to fix and strengthen it. I was thinking of just using liquid tape to seal it, but then started thinking it would still be weak. This is on an electronic toy guitar, so its going to get flexed.

Also just out of curiosity, wondering if at the end of the wire (see 2nd photo by screw driver tip), that copper I can see by the strainer is that black taped wire at the inside pcb board. Also show are 4 wires (Red White Green Black)


View attachment 148826

This is the other end of the wire, inside the guitar.
View attachment 148827

Hi,

This looks bad enough to me where I would redo the entire thing. That means cutting the cable then stripping the wires back to bare wire, then reconnecting them and then covering with heat shrink or something like that. That's the only way to be sure. The only catch is that you have to place the heat shrink on the cable and/or wires before you solder them back together, and be careful not to partly shrink the heat shrink tubing until after you are done soldering and can slide the heat shrink tube over the joint properly before shrinking with a hot air gun (soldering irons suck for doing that).

The best wire for this kind of application would be the wire used for things like computer mice. This type of wire is made to bend and bend and bend and not break. It's actually a tiny coil of wire with very small diameter so it looks like regular wire until you look really close. The wire itself is flat copper, but it is wound into a tubular coil, and that tube looks like a regular wire from a distance.
This would mean replacing part of the cable not just fixing the joint. The part that flexes the most would be replaced with this new type of wire. It's not an easy fix however.

The thing about using heat shrink is that it may come out too stiff and that may impair some physical movement, but there are not that many choices here. You could find another cheap device and steal the cable off of that and replace this damaged one with the brand new one, or find an older discarded device as long as the cable is still in really good shape.

The thing about these kinds of repairs is that the engineering that is behind these cables is very carefully thought out and it's not easy to duplicate that with everyday fixes. It takes more thought to get a decent and long-lasting repair going.

There is also the possibility that it will break again and need repair a second or third time, or even more. I don't know if there are any wireless options for this device but you could look into that. That would eliminate the cable, but bring in the need for batteries in the main device housing. Part of this all depends on how bad you want this to work out.