Common Soldering Mistakes | Soldering

The video starts by comparing a recently stripped, clean copper wire with an oxidized copper wire that has been exposed to air for a long time. The clean wire is shiny and pinkish, while the oxidized one is duller and less copper-colored due to an oxide layer that disrupts the soldering process.

There are two main ways to remove the oxide layer: mechanically, using sandpaper to abrade it away, or chemically, by using rosin core flux.

The video demonstrates tinning a clean copper wire. After adding rosin, placing it in a vice, and heating it with an iron, the solder flows smoothly, resulting in a nicely tinned piece of copper.

When attempting to solder an oxidized copper wire, even with flux, the solder does not make good contact, leaving brown unsolderable areas. This is because the oxide layer on the surface disrupts the alloying process, leading to a poor solder joint.

To make a better solder joint on an oxidized wire, the oxide layer must be removed. The video shows stripping a new piece of wire and then using sandpaper to mechanically remove the oxide layer before applying flux and heat, which results in a nice, clean tinned copper wire.