How to Solder a Mechanical Keyboard

If you are thinking of building your solder mechanical keyboard, you may need to learn how to solder first before doing so.

There are two types of keyboard electronic PCB’s ( PCB = where the switches and electrical components sit on):

• Solderered or Through Hole PCBs
• Hot-Swappable Switch PCB

The first is where you will need to learn how to solder a mechanical keyboard.

The second does not require soldering but you will need to insert the switches carefully so you do not bend the pins.

Since you have a soldered Pcb, let's Learn How To Solder a mechanical keyboard!

I made the video if you want to watch it instead of reading lots of lines of text!

If you want to check your keyboard by making, then you can test all keys of your keyboard by going to the Keyboard Tester website.

You can then determine if the mechanical keyboard you made is working properly.

What Tools and Parts do you need to solder a mechanical keyboard?

Parts:

• Mechanical keyboard PCB
• Mechanical switches of your choice
• The switch plate with the correct layout
  

Tools you will need:

• A Soldering Iron (Temp Variable or 30-40W soldering iron will work)
• Good solder (Multicore, Kester, and other good brands exist)
• Solder Sucker or Desoldering Pump (in case you make a bad join)
• Brass Ball or Brass Brush
• Metal Tweezers (any will do really)

Optional tools that may make your life a little easier:

• Flux Wick
• Multimeter

Now that you know what tools you will need let’s go into a little more detail about the different tools and what specifics you will need:

Soldering Iron Discussion

Obviously, for soldering, you will need a soldering iron. 

There are many soldering irons on the market so feel free to use whatever soldering iron you like but here are a few that we recommend:

• TS80 (portable, recommended for a hobbyist)
• TS100 (portable, recommended for a hobbyist)
• SH72 (portable, recommended for budget)

I highly recommend these irons as they are both relatively cheap and of good quality. 

TS80 and TS100 have temperature control options as well as OLED screens that display their current temperature. 

SH72 does not, instead it has an analog temp variable knob making it much cheaper. 

The awesome thing about them all is interchangeable tips and you can get many different compatible tips for whatever soldering purpose you require. 

The SH72 specifically supports official Hakko tips!

• Hakko FX-888D (desktop, hard-wired)

The Hakko FX-888D is my personal choice in irons but it is a bit more of a luxury option than a necessity, it is a professional soldering kit that comes with a stand for your iron, sponge, and brass ball all in one. 

It also has a selection of soldering tips that you can easily swap out too for different purposes. 

It is great for making USB Cables or building keyboards as a hobby!

Solder

Whilst many different brands and types of solder exist, we recommend that you use a high-quality 60/40 or 63/37 leaded solder available from most electronics stores.

Kester, Multicore, Duratech, and many quality brands exist. 

There are cheaper options but it is clear that they either result in more difficult soldering attempts (due to quality) or bad soldering joints.

We suggest you use a 0.70mm gauge solder as it is the sweet spot for soldering mechanical keyboard switches however a 0.50mm or 1.00mm solder diameter will also work.

If you are using a thinner gauge of solder you may need to add a bit more while soldering a switch or even go over it again to ensure you have no cold joins or not enough solder in the joint.

If you are using a thicker gauge of solder be careful not to add too much or you may end up with bulging joints which whilst still functional are not the most pleasant to look at, BUT they will work.

Professionally speaking they are not within acceptable soldering standards. 

So if you want to get good at soldering now is your chance!

Since this is your first or second rodeo, however, if you do get a bulgy solder joint it is completely fine!

Do not keep trying to heat it with the soldering iron to fix it because THAT is how you break pads!

I highly recommended these solder suckers:

• Engineer SS-02 (aluminum casing)
• GOOT Desoldering Tool

These two are the go-to tools for myself and the vast majority of the mechanical keyboard community due to their high-quality design and robustness.

If you are lucky enough to have access to an automatic desoldering gun this will make removing solder much easier, but they are in no way necessary and are quite expensive.

I can recommend these two desoldering pumps (please note that there are 220V and 110V versions depending on what country you live in – choose wisely):

• Hakko
• S-993A 220V (CN/AU)
• S-993A 110V (USA)
• Brass Ball Soldering Iron Tip Cleaner

The last tool that you require before you can solder is a brass ball or brush, this tool is used to clean off any impurities from your soldering iron tip to get the best joins and keep your iron in good condition.

Usually, these impurities appear after you solder a few switches. 

You simply wipe the tip against the brass ball to remove the impurities, in the soldering iron with solder again and keep going!

These can be found at any electronics store and most hardware stores as well.

Safety is not your priority But Your Only  Prioroty!

1. Before you start soldering make sure that you are in a well-ventilated area.

Use a fan or a fume extractor to remove any smoke that is produced when using the soldering iron. 

This smoke that is produced can give you shortness of breath or encourage asthmatic symptoms in the short term and even worse conditions in the long term.

2. Your soldering iron is very hot so ensure that you never touch your soldering iron!

3. Always wear safety goggles when soldering as smoke, molten solder or flux may get in your eyes

4. Finally, when you are finished handling leaded solder make sure to wash your hands with soapy water immediately after soldering. Ingesting even trace amounts of lead is not good for you.

How to Solder Switches to Your Mechanical Keyboard

Soldering is all about practice and if you follow this guide you will be equipped with all the knowledge you require to begin soldering like a pro.

Before we begin you will want to test your PCB to make sure all switch sockets work.

Plugin the USB Cable into the PCB so we can test it. 

It should make a connect sound from Windows. 

If it doesn’t it may not be programmed yet, but this is unlikely.

From there you will want to use your metal tweezers to jump the switch pads. 

You will not get an electrical shock because USB ports only deliver 5 volts which are not enough to harm you.

Place one end of the tweezer on one pad and the other on the connecting pad. 

Do this for every switch pad which looks like this.

If the PCB is working properly then the key will register as being pressed on the tester.

Step 1 – Place the switch plate on top of the PCB.

Step 2 – Place switches on the corners of the switch plate and push them in. Make sure it is aligned and the plate is not bent.

Step 3 – Place the rest of the switches in and make sure you place the switches in the right layout according to your tastes. 

Each kit has a different layout. 

For example, you can have a larger space key or split shift, etc. 

You can read the manual for your kit to see where those switches need to be placed, or you can use keycaps to space the switches properly.

• Also check if each switch has the pins popping through and if they are not, make the switch out by pressing against the housing and straightening the pins. 

The switch may not be damaged but sometimes it’s easier to chuck another fresh one in there just in case. 

Save the other switch as a backup.

• Once you have checked all the switches are flush against the PCB, then you can turn on your soldering iron.

Step 5: Turn on your soldering iron and set it between 330-360°C.

• Many of the ‘pros’ believe over 350*C is too high, it’s not. It is better to heat a component for a shorter amount of time with higher heat than a longer amount of time with lesser heat.
• It also depends on the temperature conditions in your workspace. If it’s cold, higher heat will help you. If it is warm, bring it down a bit.

Step 6: Using your brass, brush the soldering tip a few times to clean it. 

Then add fresh solder to it, we call this tinning the iron and it will help transfer the heat into the component you are heating.

Step 7: Get the iron, tin it again if you have not already and place it onto the pin and the pad at the same time and with medium pressure.

• Leave it on the pad for approximately 2 seconds to heat up and in the last 2 seconds, you add solder to the pad and leg, but not the soldering iron. 

You want to solder on the components because it will bring   flux onto the joint and help the metal spread evenly.

• In total, you should be on each switch for a maximum of 3-4 seconds. More than 5 seconds and you could damage the switch.
• The novices love to hover from the pen and pad. 
• Do not hover as you won’t get heat onto the joint which is the whole point of soldering.
• Do not be scared to put a little pressure on the pen and pad, but don’t overdo it!

It needs to be able to take the heat so it can suck up the solder. 

Low or no heat means a bad solder joint is about to happen! 

Step 8: You can tell when you have done a great soldering joint when you see two things: 

The joint is shiny and concave and you can still see the pin of the switch. 

If you can’t see it or you have a blob, then you have put too much solder, or it could be the following reasons:

• The solder is not hot enough. Use a higher temperature between 350*C – 360*C.
• You are blowing onto the joint while soldering or there is a cold wind breeze. This cools down the bad joint.
• Your solder does not have flux, so it is not joining with the metals easily. 

Flux helps in the soldering process. 

Use a flux pen and see if it helps by dabbing it onto the joint before soldering again.

Step 9: If you have done everything correctly you can quickly test the switch with a multimeter. 

Set your multimeter to continuity mode then place your probe onto the two pads and press down on the PCB where the switch is.

If it beeps or shows ‘0’ it means the switch and your soldering have worked! Nice job!

Step 10: Now repeat for all the other switches and don’t forget to remove impurities or discolorations with your brass ball when you see it on the tip.

If not you may have a faulty switch. 

Test it with a multimeter by putting it into continuity mode. 

Place the two probes where the switch legs are.

If it shows no resistance or it beeps when you press the switch down, it means the switch is working, but the specific key may not be programmed or the diode for that switch is not working.

If however, your switch is not working you have to use your desoldering pump to remove it.

• To do this you simply need to reheat the joint with your soldering iron at a temperature of around 380-400*C.

We need the solder to be hotter because the air used to suck it out will cool it down.

• Without removing the iron, position the solder sucker above the joint and click the button on the side of your sucker so it will suck the solder out of the joint.

It uses air to suck the solder out, so the solder must be hot for it to come out.

• If there is any remaining solder you may be able to reheat it and make another attempt at sucking it up otherwise add some more solder and then try again.

Desoldering is hard to explain in the text so if you have any issues be sure to watch my two videos here on how to desolder!