Magnet to pull wires across heat shrink

[granterpower1311]

Hey, I found a useful tip to pull wires through long heat shrink.

I put a ring around a ring magnet.

Step 1: thread wires through ring
Step 2: Using a magnet, from outside the heat shrink, pull wire though heat shrink.

Is this useful? Or is there already a easy way to pull wires through heatshrink that is too long to thread through by hand.

[IanB]

Is this useful? Or is there already a easy way to pull wires through heatshrink that is too long to thread through by hand.

What is the reason to thread wires through a long length of heatshrink?

[Ian.M]

I would assume for making up vehicle cable looms or similar.

Thread sleeving over a rod (or stiff wire) that is significantly smaller than the I.D.
Attach wire to be sleeved to end of rod, taping the joint smooth.
Tension wire lightly.  Slide sleeving off rod onto wire.   If you use something like fence wire or a fish tape, tens of meters of sleeving can be applied in one piece.  For really long non-porous sleeving, a low pressure compressed air supply connected to the far end keeps it open and reduces friction while pulling as constricting the drawing end as you grip it inflates the rest of the sleeving.

[granterpower1311]

I use stepper motors and with 4 wires coming from each. It gets messy. I organize them with heatshrink

[Delta]

Is this useful? Or is there already a easy way to pull wires through heatshrink that is too long to thread through by hand.

What is the reason to thread wires through a long length of heatshrink?

So that your long wires will have heatshrink around them.

[granterpower1311]

yes!

[Alex Eisenhut]

Have you considered using, um, a cable with the wires already inside? 

[granterpower1311]

thats wizardry!

[ericloewe]

Interesting method, but I have to wonder how often you deal with heatshrink long enough to make this process worthy of optimization.

It might be less trouble to just wrap your wiring in vinyl electrical tape, self-adhesive tape or that felt tape some car brands use to wrap looms.

[SeanB]

Good idea, I have used nylon air line as extra cable protection before, and this will make getting the leader through easier. Reason for the nylon is that it was going in a cable tray or a conduit with other cables, and while there was not an issue with EMI driving incandescent lamps and a relay coil over the cables I did want extra protection for the thin cabling in case the conduit or tray got wet from being outside.

[Ian.M]

Sometimes you need an oil, fuel or chemical resistant loom.  Most tapes except silicone self-amalgamating tape have poor chemical resistance - either the adhesive lets go or the tape body becomes gooey or brittle.   However heatshrink rated resistant to various fluids is readily available, and then you only have to worry about any joints.   If they are overlapped slightly then covered with a compatible adhesive lined heatshrink, the whole body of the loom can be fluid tight.