Building your own keyboard is a rite of passage for those caught up in the ergonomic rabbit hole. So, it was only a matter of time before I went all the way and did so.
However, as a complete noob when it comes to soldering, I had a rough time getting started. I hope that this brief guide saves you hours of anguish!
How to (not) solder#
After procuring all the parts required for our keyboards, my friend and I proceeded to get absolutely nowhere with our soldering. Little did we know that the tip of my usb C iron (TS80p) was oxidized. We thought it was because the iron wasn’t getting hot enough or staying at a consistent temperature, and I promptly went to buy a Weller soldering station (which I would also not recommend, reasons to follow). I also promptly oxidized the tip on this machine as the sponge they give you in the kit is a travesty and you should not do that.
My tips#
DO NOT use wet sponges on the iron#
The very first thing I would say that would have saved me much anguish is not using a wet sponge. The fact that many soldering stations ship with one instead of what you should be using (a brass sponge/wire) is a head scratcher.
Water (if not using de-ionized water) will very quickly oxidize a soldering iron tip, and the temperature difference (ambient room temperature vs 350-400C) is enough to actually cause the iron tip to crack over time.
Use brass wool. No water. Get this thing and use it instead.
Use Flux#
The second thing I would recommend is to use flux when you are soldering. And, not liquid flux, but something a little tackier that won’t immediately vaporise when you hit it with your iron.
Tin the tip#
The reason that I had no luck was that the tip of my iron was not tinned, and that is how you “dry out” your iron very quickly, causing black/grey oxidation to build up. So, tin the iron when you first turn your iron on AND AGAIN BEFORE YOU PUT IT AWAY.
Don’t go too hot#
The consensus on the internet about soldering temperature is to keep the iron just above the melting point. When your tip is oxidized, you have to bump to 400 degrees C or higher (some usb irons max out at 400) and as such you will be having one hell of a time to get solder to melt. I use lead-free solder, so I shoot for around 360 C give or take.
Many will say leaded solder is more forgiving and it very well may be, I just don’t have experience to compare.
Traditional irons are lame#
The TS80p is a pluggable tip with a 3.5mm TRRS jack. The Weller WE1010 station has a heating element that I will call “legacy” - it does not go all the way to the tip of the iron, and the thermometer is located away from the tip, giving wildly inaccurate temperature readings. In addition to the previous point, the iron stays heated at a certain temperature with no auto down-regulation (they’ll shutoff after 1-2 minutes if you have it in settings). So oxidization is more likely on a traditional iron.
What you want is a JBC C245 or C210 compatible iron or clone station. You don’t have to buy the authentic tips, and there are videos online of the cloned tips from Aliexpress actually being just as good (or better!) than the authentic tips. I thought about getting a full station, but instead got a capable USB C iron that seems to very much hold up to the wired stations. It’s only 100W, with many stations being 220W - so take that with a grain of salt, but for a keyboard or two, it has held up just fine. I may consider a TC22 or Fnirsi D200 station in the future, but will cross that bridge when we get there.
If you are interested in the iron I am using, it is the Fnirsi HS-02.
Tip recommendation#
Most irons will ship with a conical tip. These are trash and put heat at a very small point. I recommend a knife/chisel tip as you can then manipulate the tip and have greater or lesser heat transfer with the rotation of your wrist.
Ventilation#
You probably don’t want to be breathing in soldering fumes, so get yourself a cheap desk fan to blow the fumes away from you. For hobby projects, a fume extractor is probably not necessary, but you can go all out on this and build your own if you so wish.
Heat the board/joint, not the solder#
I cannot have a soldering tip post without the classic Louis Rossmann meme: “HEAT THE BOARD!”
I didn’t have issues with this as I remember the above, but when first starting, some think that soldering is about heating and applying solder. It is not. It is about heating the components to the point they will accept solder. This makes a massive difference.
The more people that learn to solder, the more we can fight for repairability, and you start to see that no board is actually dead, it probably just needs a new chip somewhere. The “literacy” that comes with soldering and the ability to repair electronics can take you from a consumer to someone that actually understands the underlying mechanisms.
As always, God bless, and until next time.
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