Some time ago I added a PID controller to my espresso machine and it came with a 2 metre thermocouple. This was clearly too long and I finally got around to shortening it at the weekend. I found myself with over a metre of thermocouple wire and since I hate waste? Time for a five minute project - make two new thermocouples. It actually took a bit longer as the first attempt was not top quality. So what NOT to do: Do NOT follow instructions on the web to twist wires together, connect the untwisted end to one terminal of a car battery and briefly touch the twisted end to the other terminal. This will result in a piss weak spark and a really dodgy connection. The thermocouple wire is just too fine to carry the current. Instead do the following: Find some carbon electrodes. I used old electric motor brushes, but any cheap AA battery has a carbon electrode in the middle (wear rubber gloves when disassembling). You could also use artists charcoal, or a soft pencil lead, but they are fragile and harder to work with. If using an electrode from a battery, break in two. You will also need car battery, jumper cables (or a portable jump start unit as I used). Clamp the two electrodes, one in the end of each jumper cable. expose a small amount of both thermocouple wires (about 1cm). Using fine pliers, preferably needle nose (strong tweezers might do), twist the very end so the wires cross. Attach cables to battery if not using jump starter, don't let them touch. Hold the thermocouple junction against one electrode and briefly touch the other electrode against it. Result - big ass spark and clean weld (hopefully). Photo of final product:
