Soldering Iron Powered Filament Joiner - Make Multicoloured Parts

I machined this out of scrap aluminium, and friction fitted it onto an old soldering iron bit. Easy to make with a drill and hacksaw though!

If anything, this part a little bit big. All you really need is the angled surface to press the two bits of filament together, and a hole to ram the soldering iron in.

To use, press the two filament parts together where the two channels join, then smooth the filament around while still hot in the groove. Remove the joined filament and carefully roll