Transformer is from soldering gun where we want 5 to 7 volts and transformer currents of 8 to 10 amps. You might be able to use radio filament transformer.
Shown is electric heater for your test tubes to around 250 degrees F. Heating coils or resistance wire about .020 inch in diameter. Resister represents resistor wire wrapped over glass fiber around metal light bulb socket in porcelain light bulb mount. Shorten about 18 inches of resistance wire about 1 inch at a time to reach desired temperature.
Anyone heating test tubes with their toaster?
Want to melt solder to drop stranded wire in? Take 3/8 inch diameter tubing about 3 3/8 inch long and smash one end in a vise. Wrap with two wrappings of 1.25 inch wide mica strips and use about 9 inches of resistance wire and find mount that can handle the high temperatures.
