Heater to Nichrome crimp ferrules insulation?

Hopefully I very nearly have a finished Reprap Prusa now. I've found these forums to be an invaluable source of information, so many thanks to all who have helped me so far!

My motors seem to be running fine, and I've spliced the Z axis wires, but the hot end still needs to be properly assembled. I'm just wondering what options I have to insulate the ferrules that connect the heater wires to the Nichrome for the hot end? My concern is that the parts of the ferrules that connect to the Nichrome might get hot, so certain materials might not be suitable. I have some insulated ferrules like this - [cgi.ebay.co.uk], might they do the trick, or would their coating be likely to melt? Alternatively I have some bootlace ferrules. Would wrapping Kapton tape around the uninsulated parts of bootlace ferrules be satisfactory? Finally, I have a piece of heat shrink tubing, but the diameter is a bit wide (I think it shrinks to 3mm) so I'm sceptical whether that would be ok. I realise I could probably order some suitable heat shrink online, but ideally I'd like to set things up by this weekend, so if Kapton tape or insulated ferrules sound all right I'd appreciate some feedback.

Thanks!

Hi Rook, hope that extruder is working okay too! I bought some PTFE heatshrink from RS online here [uk.rs-online.com]
I don't think there's much else but PTFE that can handle the heat near the hot end. Kapton tape will probably be okay to get it going. For the thermistor, I put on piece of PTFE tube over one leg, then the second slightly shorter piece over the first PTFE tube and the second thermistor leg. This provided a bit more support for the tiny and weak thermistors that I have, the ones recommended by the wiki.
I also used the recommended bootlace ferrules, [uk.rs-online.com] because all other ferrules I could find were far too big, especially for the thermistor wire.
Good luck!

also you may want some tin wire. here is a place to start [parts.digikey.com]

the reason is copper wire will oxidise and not conduct again after cool down

@droftarts

Thanks for the advice. I've avoided using the insulated ferrules, and went with the smaller uninsulated ones (about 1.5mm diameter) and they seemed to crimp nicely. I also coated the ferrules in Kapton tape for now. So far nothing has exploded, and I managed to extrude some PLA and obtain believable temperature readings for the hot end.

@jamesdanielv

My ferrules are apparently made from copper with tin plating, so hopefully they will do the trick!