Soldering Without Fear

This is the one thing that separates a good joint from a bad one. Touch the iron to the pad and the pin together for a second or so, then feed solder into the joint itself, not onto the iron tip. The heated metal melts the solder and pulls it in. If you melt solder on the tip and drop it on, you get a grey blob sitting on top that looks connected and is not.

A blackened tip will not transfer heat, and most "my iron is broken" moments are really just an oxidised tip. Wipe it on brass wool every few joints and leave a little solder on it whenever you set the iron down. We would recommend brass wool over a wet sponge, since the sponge cools the tip every time you use it.

Spend twenty minutes joining scrap wire before you touch anything you care about. You are training two things: how long the iron needs on a joint, and how much solder is enough. Both are muscle memory, and both are much cheaper to learn on wire than on a Pro Micro you have to desolder afterwards.

Do the flattest components first and the tallest last, so the board still sits level while you work. On a handwired build, tack one corner of each switch first, check the plate is sitting flat, then go back and finish every joint properly. Fixing a crooked switch is far easier before forty wires are attached to it.

You will make a mistake, and that is fine, so long as you can reverse it. Desoldering braid pressed onto a joint with the iron wicks the old solder away, and a solder sucker handles bigger blobs. Knowing you can undo a joint takes most of the fear out of making one, which is usually what makes people hesitate and overheat a pad.