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

[Dave Kendall]

On Dec 21, 2007, at 23:38, DTK wrote:

>> 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.

That makes a lot of sense. The factory did a lot of automotive wiring 
work, which might have a bearing on it.... I also picked up some 
asbestos sleeving, which IIRC was used on wiring looms for Jaguar motor 
cars. Back when I had almost no money at all, I cut some short lengths 
of it and used it as a sort of ersatz strain relief for the el-cheapo 
1/4" jacks that I also got from the dumpster. Yikes!

As a matter of fact I've just been using some hook-up wire got from the 
same source - still got lots of it but the colours are a bit weird.... 
Pink or purple anyone?  :-)

cheers,
Dave