[sdiy] Heat shrink tubing driving me crazy....

[DTK]

> Amongst the haul I got was loads of pre-cut heatshrink, except that some 
> types/lengths of it wouldn't shrink. It had a very slight gluey layer 
> inside, which melted and then solidified when heated - all I can think is 
> that it *wasn't* heatshrink  but some sort of 'covering'

What you have there is probably a heavy-duty heatshrink used in the CATV and 
telephone industries.  It's used at splice points and connections to 
mainline equipment, and the gluey layer is a weatherproofing agent which 
melts and seals everything up.

It does shrink, but only under sustained direct heat, like from a torch. 
You pretty much have to hold a flame to it, hot air won't make it shrink... 
it's designed that way so that the heat generated by the equipment doesn't 
make it shrink further and split.

It does come in a lot of different sizes, very small to very large, so it's 
possible that someone managed to get it mixed up with "normal" heatshrink. 
It would be hard to tell the difference on the smaller sizes.

Or, as was also mentioned, it might just be a dry-shrink kind, in which case 
it's useless :)

DTK