Solder seal butt connectors are made of a clear, heat shrink tube, with a low temperature solder ring in the middle. On either side of the solder ring, there is a colored ring of heat-activated ...

There are several ways to splice automotive wires. Gelfand’s preferred method is to both crimp them and soldier them together, before adding heat-shrink tubing with built-in adhesive for protection.

Sometimes, working in tight spaces, I'll resort to butt or blade connectors with some heat shrink over them. Soldering on a bench is one thing, but making a good solder while lying under a car is ...