Hey,I'm working on a 15kv 120ma nst tesla coil build using a 5.7inch pvc.The length of 26 gauge magnet wire needed for 25 inches of winding worked out to be just over 2,000 ft of wire.So to be safe, I bought 3,000ft.
However, halfway through winding the wire ran out! I'm not sure if they sent me the wrong length of wire, or what happened, but I didn't have time to have more wire shipped and redo the winding. So I decided to join the wire with another spool of around 1,500ft 26 guage wire. I burned a few millimetres of enamel off each tip and connected them with solder. The joint was barely larger than the wire. Then I coated the solder joint with a bit of superglue, and dipped the wire in varnish and let dry several times. Then I wound the rest of the coil. I will be coating it many many times with varnish.
I've heard that it is a really bad idea to join wire halfway through a secondary winding, but hopefully the job I did will hold up.