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I have some 18 guage wire only it is solid not stranded will it work with the h-1 kit?

yup, it'll be fine... I use 20ga single strand wire, so 18 will be fine.. I have my live stream going right now if you want to see any part of my h-1 printing..

Guanu

It will work, but you may find that the solid core wire will eventually give out with excess movement (extruder motor and X axis motor).
I use 24 gauge CAT 5 cable, works the best, and I can a twisted pair per stepper motor wire. For the extruder heater I use lamp cord wire, I think its 18 gauge.

I think you'd have to see a lot of repetition to get failure in solid core wire. As long as the bend radius isn't extremely tight I think you'd likely see years before there was a failure.
But I'm speculating.

Ideally, you should use stranded wire. On a CNC'd mill, lathe or router you should definitely use stranded wire since bad things happen with an electrical failure. On a 3D printer not much bad will happen other than losing a print in progress. But, if you can swing it, do it right with stranded. If the solid wire ever did start to fail it might be tricky to trouble shoot.

cheers,
Michael