Soldering tips

While soldering may seem intimidating for beginners, it is really simple and straightforward.

I would suggest to try soldering on some spare wires first. Then do a small handwired project like my budget macropad: you cannot really mess up anything with a handwired project. PCB and SMD soldering is another case (parts and the PCB itself can be ruined), but don't worry about this yet.

Soldering iron

Soldering through hole stuff is pretty undemanding. You need a soldering iron with a pointy tip and that's it. The iron shouldn't be too bulky, but anyway, almost any iron will do the job.

You don't need much power or fancy features like temperature presets, auto-sleep function etc. You can buy a cheap iron until you're sure you like this hobby.

Solder wire

I use 0.8 mm diameter leaded solder wire. Anything about 0.6-1 mm would probably work just perfectly.

Avoid cheap solder wire from aliexpress though: they stink, resin bubbles exploding all the time. Buy your solder wire in a local shop instead.

The general store I usually go to sells only one type, it's a local/noname brand. I bought 100g for about 6$ and this amount will last me for several keyboards, probably dozens of them.

Temperature

I use my iron at about 340°C. I've set this at the very beginning and don't bother with it. It would probably work the same at 360 or 300.

If you cannot set the exact temperature on your iron, you can still compensate with how long you hold the tip to the joint. If the solder material melts instantly (probably too hot iron), you hold the tip for a shorter time.

Protective measures

Keep your desk tidy. Avoid sudden moves. Try not to burn yourself or stuff around you. Wear protective glasses. For longer sessions room ventilation is important (open the window and/or you can place a fan on the desk).

Soldering technique

1. Practice on spare wires.
2. You may prepare your contact points with some resin. (The more weird the joint, the more this helps.) Simply put some (very little) flux/resin on the points/wire ends/diode leg etc. to be joint.
3. Turn on your iron.
4. Once your iron is heated, put some solder on its tip by touching the solder wire.
5. Touch the iron to the wire for a short time: you heat the contact points and the fluid solder material flows to the contacts. Remove the tip from the contacts and the solder material becomes solid.
6. Clean your tip on that brass sponge/ball thing. (I find using wet sponge barbaric.)
7. Turn off your iron.
8. Wash your hands because of the leaded stuff.

Soldering SMD LEDs

"I’ve soldered dozens of surface mount LEDs without burning any out. Get good, thin 60/40 solder, set the iron for 300, and go to town. Tin the first pad with a nice blob, line up the LED, heat the contact and the blob, release when it sticks. Use your tweezers to position, reheating the one pad and twisting to get all of the contacts lined up. My tweezers spring closed and open only when you squeeze them, so after I get the first contact soldered and the LED in place, I clamp the tweezers over the LED to squeeze it to the PCB. Reheat that first contact, and it presses down onto the PCB flush - pops right into place. Heat and push solder into each of the other three contacts while the one corner holds it in place, and then move to the next LED. (ringmaster, 2020)

Great! Now you know how to solder. Grab your iron and start your first keyboard project.