I've tried to shrink the heat shrink with a heavy duty heat gun and a lighter. neither one do anything other than turn it clear.

it's got to fit into the heater block. i think that any insulation needs to do two things:
1) prevent shorting the leads with the metal block
2) provide thermal conductivity to the thermistor

i think that kapton would suffice for both of these.

thoughts?

*EDIT: i tried the soft heat shrink tubing, NOT the hard PTFE tubing.

Edited 1 time(s). Last edit at 11/28/2013 05:28PM by bryancostanich.

PTFE is a form of Teflon. It will not shrink when you heat it. Heat shrink is a completely different animal. The PTFE tube goes over the wires to insulate them. The heat shrink goes over your solder joints.

Are you trying to fit the themister in the block or insulate the wires?

sorry, not the PTFE. i tried the little piece of heat shrink tubing. it only shrunk a fractional amount.

never mind, i snipped a bit of the black heat shrink tubing and it worked just fine.

the little piece of clear heat shrink stuff that was in the kit (and it said use the clear piece) wasn't worth a shit. the black stuff worked great.

to be clear, i wasn't using the long piece of hard PTFE.

If you are talking about a RepRapPro kit then yes they provide a piece of ptfe heatshrink for insulating the thermistor that goes through the heater block.

It does shrink but needs a high heat source such as a butane torch or hot air station which is what I used.

If you used normal black heatsrhink it's going to smell and melt and be a big mess when you use the machine.

I've just replaced a thermistor in one of my RepRapPro machines because it failed and have had to do this procedure this week.

Ben

uncle bob:

[www.polyflon.co.uk]

They expand ptfe tube when it's heated it then returns to its original size.

Ben