There are several things that can be done to help from melting and burning the insulation on hookup wires. First check the temperature of your soldering iron. If it’s too hot it will damage the contacts and cook the solder. Always mask off the body or other surfaces that could get damaged by solder drops or spitting rosin inside the solder.

I’ve used a Weller TC-202 soldering station for many years and tip # 7. You can use several different numbered replaceable tips. I’ve used # 7 & # 8. It works great when using rosin core solder and make sure to flow your solder and don’t use too much. The next thing I do is use a tinned Teflon coated, 7 strand, 22 gauge hookup wire. It comes in a variety of colors such as black, white, red and several others. It is really handy when soldering contacts over and over again.

I like rewiring switches and don’t like using the standard PVC wire as the insulation usually shrinks and melts beyond use. Teflon wire cost more but it will last much longer than most other hookup wires. I like using cloth braid wire too as it is easy to solder and you don’t have to worry about it melting or shrinking.