At 11:56 PM 6/5/2013, veegee wrote: >Hi all, > >I'm making a small melting tube that can quickly melt wax and pour on >demand. It's simply 3" long piece of 3/4" copper pipe with uninsulated >NiCr wire to be wrapped around it. What's the best way to wrap the NiCr >around the tube without shorting it? One option is high temperature >manifold paint, but I'd rather find a more thermally conductive (yet >electrically insulated) solution. 1) Kapton tape - works reasonably well. Wind the NiCr wire tightly=20 on the insulating layer with a cotton thread as a spacer. Insulate=20 the free ends of the NiCr with Teflon tubing, then twist the=20 insulated free ends together so as to keep the whole works tight on=20 the tubing. Insulate the outside of that as desired to minimize=20 radiation losses. 2) Consider using the copper tube as a shorted 1-turn secondary on a=20 transformer. In other words, wrap however many turns of insulated=20 wire you need around the pipe and feed with enough high-frequency=20 current as you need to bring the pipe up to the desired temperature. Note that the primary wire does NOT get hot, so space it away from=20 the copper tube if desired. Better yet, wrap the copper tube with=20 insulation, then wrap the primary coil over top of that insulation. Details left as an exercise for the student . dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .