Repairing cable outer sheath

[GMB]

When I need to add some covering to a cable or whatever I would normally use heat shrink tubing as this makes a very satisfactory and strong repair.

But what if you can't fit heat shrink over the cable for some reason?

I have always found insulation tape to be truly hopeless. If it looks like it is doing anything when you turn your back it will fall off. Seriously unsatisfactory in my books.

I have tried "self amalgamating" tape (I think that is what it is called) but I don't think it sticks so well to the cable - just itself (obviously).

So what do others do to make a satisfactory outer repair to a cable in this situation?

[jay_oldstuff]

I do remember a product I saw at a stage lighting triad show. It was a cross between self amalgamating tape and heat shrink. You wrapped it round then heated it with a hot air gun whereupon it tightened up and adhered to itself and the cable.

It was very good indeed sadly I can't remember the manufacturer. I've tried looking for it myself a couple of times without success.

Jay

If you stretch the self amalgamating tape when applying it (almost to breaking point, it is a big stretch) it will conform to the cable and form a waterproof cover. And if you 'flash' over the cable with a blowlamp it activates the surface making a bond more likely. This is used (by corona discharge these days) to print on plastics like crisp packets.

[threeseven]

Try this :-

http://www.marine-super-store.com/po...artno=99081331

I believe Loctite also have a similar product.

[dseymo1]

This is used (by corona discharge these days) to print on plastics like crisp packets.

Sorry, I don't understand that bit

[m0cemdave]

Originally Posted by jay_oldstuff

I do remember a product I saw at a stage lighting triad show. It was a cross between self amalgamating tape and heat shrink. You wrapped it round then heated it with a hot air gun whereupon it tightened up and adhered to itself and the cable.

It was very good indeed sadly I can't remember the manufacturer. I've tried looking for it myself a couple of times without success.

Jay

I have used that stuff. I'm sure it came from either Farnell or RS, but I can't find it in a web search. I do remember it was very expensive, but we had to repair an audio multicore the day before a major festival.

It is a specialised version of adhesive-lined shrink sleeving, which comes as a sheet of heatshrink sleeving with hot melt glue along the edges. You attach one edge to the cable, then wrap it and it sticks to itself, after which it can be shrunk in the normal way.

Maybe worth searching for "cable repair kit" or similar.

Originally Posted by dseymo1

Sorry, I don't understand that bit

The surface is 'activated' by the corona discharge so the ink sticks, I should have been clearer.

[DAVEHALL]

We used to use a cable repair kit in heat shrink form at work -it consisted of a length of heat shrink tube cut open ( rectangular shape ), with a metal join piece .The edges of the heat shrink were thicker than the rest, to take the metal .The rectangle was cut to length ,wrapped round the cable ,the metal slid over it and the lot heat shrunk .It was used on large cables ( something over 1" external), and most likely cost an arm and leg, as it replaced the need for a cut & shut job on working cables where only the outer was damaged .

[jamesperrett]

Originally Posted by merlinmaxwell

If you stretch the self amalgamating tape when applying it (almost to breaking point, it is a big stretch) it will conform to the cable and form a waterproof cover.

I'd echo that stretching is the key to making self amalgamating tape work. In my day job we use it for waterproof joints that will be used at depths of up to 6000 metres in the sea. We also cover the joints with decent insulation tape as self amalgamating tape tends to be damaged by UV.

James.

[GMB]

I have never felt that self amalgamating tape was all that adhesive to anything else, e.g. the cable. Yes, I understand the need to stretch it but it always seemed to me that it held in place mainly by friction.

I willl try the idea of heating it. I suppose I could also try to spread some rubber adhesive on the cable first.

There are two aspects to a repair like this: sealing the cable which I guess the SA tape does OK, and then there is holding the gap together which I am less convinced it will do well as it's rather soft and not so sticky.

But perhaps I should revisit it in the light of your comments.
I've seen large-scale heat sealing kits, e.g. as used to repair power cables in the road, but never seen a small version of them.

[DAVEHALL]

Originally Posted by GMB

But perhaps I should revisit it in the light of your comments.
I've seen large-scale heat sealing kits, e.g. as used to repair power cables in the road, but never seen a small version of them.

The heat shrink repair kits would accommodate cables from about 1" dia upwards , with a resin heat activated adhesive incorporated in the inner of the heat shrink .

But as said - I suspect that these would prove expensive .