I use it for many purposes but have never seen it do anything like that. Must have some kind of acidic reaction with the cable material. Thanks for the tip Michael.

There is a general problem with soft PVC in all sorts of applications. The plasticiser is leached out far too readily, hardening the PVC, and sometimes softening whatever it is in contact with.

My worst experiences with this have been with older vehicle tyres and inner tubes. If there is no rim-tape handy, the temptation is to use (PVC) insulating tape, which seems ideal, but … the plasticiser moves from the tape to the inner tube, hardening the (sharp) plastic, and softening the rubber, so part A cuts through part B. Not at all pleasant especially in a foreign country eg the Pyrenees.

What to use instead? I have found duct tape to be OK, as it has polythene as its plastic, not PVC. Polythene does not include plasticiser (I think!), and if you rip it lengthways, rather than cut it, the strength is not sacrificed.

Tim Stevens

Also watch out for expanded polystyrene – it eats insulation.

What a horrible thing to happen.

I have found a lump of BluTack useful for putting on the end of boring bars to reduce chatter. I think its mass changes the natural frequency of vibration of the boring bar. I have been keeping the lump in a plastic box but after reading this thread I am going to find a metal tin to keep it in!

Rod