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Desoldering, Mill-Maxing, And Why You Might Want To Learn Both

Jan 13, 2025

Thanks to StoryboardTech’s fantastic article, you finally learned how to solder! Or at least, you’re committed to learning. So, what’s next? Well, if you’re brave enough, why not learn how to desolder as well? And when you feel confident with that, how about Mill-Max? You don’t necessarily have to know or learn how to solder before learning how to desolder or Mill-max, but in my opinion, getting comfortable with soldering is a great step towards learning how to do the other two, and if you know how to solder, you can practice desoldering and mill-maxing to your heart’s content since you’ll already have the tools from learning how to solder! Well, at least most of the tools. Let’s start off with the good ol’ disclaimer section first, however. Disclaimer

These are my own opinions and my own thoughts, and if I’ve learned anything in life, it’s that we all do things in slightly different ways. Whether it be deadlifting, desoldering, Mill-Maxing or even baking cookies, a lot of times, there is no single right way to do something. There may be useful guidelines or good things to know, but please know that just because I touch on a desoldering method or Mill-Max strategy, it doesn’t mean that it’s the method that you enjoy or works best for you! If you find success with using a desoldering pump, would rather purchase a desoldering gun, or really enjoy using desoldering wick, that’s fine. In my opinion, each desoldering strategy has its place (wick for hard-to-reach places or delicate areas, pump for when you want a bit more “control” and don’t want to burn a pad or for a few quick switches, and a gun if you desolder a bunch of PCBs or have sat down for a lengthy desoldering job), and both the tape method or switch method for Mill-Maxing definitely work, so I encourage you to find what you like best for each situation you may find yourself in. I’ll only go over the things or brands that I have personally tried and had success with, and just because I don’t mention a specific brand doesn’t mean that other brands won’t work. And, just like with soldering, you don’t have to buy expensive equipment right away. Many hobbyists have used a desoldering pump and wick for years when it comes to desoldering versus buying an expensive desoldering gun. I also recommend learning how to solder first, then learn to desolder, and then, Mill-Maxing being the third thing you learn, because soldering is always useful for desoldering (and obviously Mill-Maxing), and is the “easiest” of the three to learn in my opinion. And once you learn how to solder, you can practice desoldering what you soldered, or understand how heat transfer works can make desoldering easier to do. Mill-Maxing has less room for error than soldering or desoldering, which is why I'd say it should be the last of the three to learn, but these are just my opinions. I’ll explain how they all work with each other later in this article. Let’s start with desoldering! Desoldering

Instead Of Including Amazon Links (Even Though I Don't Get Any Sort Of Kickback), I Figured I'd Just Post Screenshots In Case You Want To Get The Item(s) On Other Websites Other Than Amazon.

Method 1: Desoldering Pump/Solder Sucker There are three common methods when it comes to keyboard desoldering, and I’ll start with the method I learned first (desoldering pump), then the second method (desoldering gun), and then the last (wick). It won’t necessarily be cheapest to most expensive, so keep that in mind. You can go from cheapest to most expensive, but I figured I’d explain my own, personal progression. I first learned how to desolder with a desoldering pump. There are many variations, each with its pros and cons, but I learned with an engineer solder sucker/desoldering pump. I’ll also be focusing on desoldering switches, specifically desoldering lead solder joints. If working with lead-free solder, I’ll talk about that in a later section, but for these first three sections, this advice is mostly for when desoldering leaded solder. The method for using a pump is that you have your soldering iron in one hand, set a tad bit higher temperature-wise than what you’d normally use to solder (or experiment, but be warned, we don’t want to burn or lift a pad. If that happens, you can fix it by soldering a jumper wire, but we won’t be going over that in this article). I solder at 350 Celsius and desolder at 365 Celsius, but whatever works for you without damaging the PCB is fine. The important thing to remember is that you want a hot enough temp to melt the solder, yet not hot enough that you damage the PCB or the solder pad.

Then, in your other hand, after making sure the pump is cocked (for the engineer, pressing down the red end), heat the switch pin that’s soldered, see the solder liquefy, then quickly place your pump’s nozzle on the liquid solder and press the suction button while removing the soldering iron, and the solder should get sucked up into the desoldering pump.

Start at 21:24 I’ve mistimed this whole process many times (and sometimes still do), and it definitely takes some getting used to, so I’d recommend trying to desolder switches on a stab tester board (after soldering switches on it) or on an old PCB where you don’t necessarily have to worry about messing up or not until you get the hang of it. Know that just because you don’t get it the first time, doesn’t mean that you won’t be able to learn! Sometimes, it takes a few rounds of heating up the solder and using the pump until the switch wiggles free. Then, do the same for the other switch pin, and you should be able to remove the switch by pulling it straight up. BE CAREFUL with removing the switch, because even if a small portion of solder still has the switch in the PCB, you may damage the PCB or leave a part of the switch embedded in the PCB if you just yank the switch out with brute force. This is also another reason why I’d recommend practicing on an old PCB or switch tester to get the hang of it. You can go against my advice and see what I mean! Sometimes, you have to make a mistake to understand it and avoid doing it.

Making Sure That The Switch Pins Are Free Of Any Solder Before Yanking

Start at 1:57 That’s basically all you have to do if you use a desoldering pump. After a few suctions, or if you notice the solder not getting sucked up, you’ll want to clean the pump out completely and/or clean the nozzle. I have small hands, so the fact that I could grip it with one hand and the soldering iron with the other, plus easily press the suction button was what sold me on the engineer, however, I do understand that if you have bigger hands, it may cramp your hand. Solder also tends to get stuck in the nozzle frequently, so you’ll have to clear that out more often than something like a big black or big blue desoldering pump, but with that type of pump, it may be a bit unwieldy. It just depends on which you get used to, are comfortable with based on how large your hands are or other factors, and what you practice with. Either style of pump works!

Make Sure To Remove Solder If You See The Pump Nozzle Clogged

Remember, neither one is “better” than the other, because we each have our own preferences, which feels more comfortable in our hand, which is more accessible for us, and other reasons as to why some of us prefer an engineer-style pump while others prefer a big blue or big black desoldering pump.

Method 2: Desoldering Gun

Now for the most expensive method! A desoldering gun. Note that I only moved to this method because my friend, who’s an electrical engineer, already had an FR-301, and I can borrow it whenever I want to (lives close by). This is absolutely a huge quality of life improvement, but the same rules still apply when it comes to being careful. If you use too high of a temperature, or you hold the nozzle of the gun too long on the PCB, you can lift or burn a pad, so it’s best to still be careful and pay attention when desoldering. Also, remember that the nozzle is HOT, so don’t let it touch your skin or anything you don’t want burnt! I accidentally burnt a bit of its own cable on accident. I also can only talk about the FR-301. Other desoldering guns may work the same way, but I haven’t used other guns. For the FR-301, I use the same temperature as I use for my soldering iron when using a desoldering pump, so I set it to that temp (halfway between 1 and 2, see the image below), wait for the light to stop flashing, which indicates that the gun has heated up to the desired temp, and then I get ready to “BRRRR!”

Start From 22:38

I used to lay the PCB flat on a table and come straight down with the desoldering gun tip, touch the solder joint of the pad that I want desoldered, and press the “BRRR” button, however, I now hold the PCB in one hand and the gun in the other, and I bring them both together in the air in front of me. Use whatever method you’d like (or figure out a combination between the two), but the most important thing to remember is that you should make sure that the gun’s tip is flush with the PCB. If you angle it, you may not get a good enough seal for the gun to desolder effectively and could also possibly break off or damage the tip.

Also, make sure like with soldering, you’re setting up a fume extractor/follow the guidelines for soldering (well-ventilated area, don’t inhale the fumes). The gun basically combines a soldering iron and desoldering pump into one, and as long as you make sure you’re getting a good seal (by making sure the tip is flush with the PCB), don’t use too high of a temperature as not to lift or burn a pad, make sure the tip is flush with the PCB, and most importantly, not burn yourself, you should be able to experience the magic that is the desoldering gun! Do note that there is some maintenance involved, however. If you find that you’re not getting good suction, and you’ve been following the steps above, it may be time to clean the gun. Cleaning the nozzle through the solder chamber, opening the solder chamber to throw away the solder, and replacing the disc filter at the end of the gun will not only hopefully fix any suction issues, but keep your Hakko in good working condition. It may take some time to see a return on your investment with the desoldering gun versus the pump, and it’s obviously a higher up-front cost, but it’s absolutely a great method for desoldering. Method 3: Desoldering Wick/Braid + Flux

This is the last method I learned, and I had to because I desoldered my two Logitech G710+ boards and ran into issues with the lead-free solder that was used to solder the Cherry MX Blues and Browns into those boards, even with the desoldering pump and desoldering gun, so I went to what my dad used to say was NASA”s only official method of desoldering (I don't think that’s true, especially nowadays, but I never bothered to correct him since he found great joy in telling me this every time) - Desoldering wick/braid. If you ever encounter a situation where a desoldering gun or solder sucker can’t fit or you need something that’s a bit more gentle, desoldering wick/braid and flux is what I recommend. Could I have absolutely kept going with the desoldering pump or gun on my G710+ keebs, especially since I was already 33% done? Absolutely. But I was getting worried that I’d be burning or lifting pads, and I figured it would be a great time to put what I learned to good use! Desoldering wick, or braid (I’ll just refer to it as wick) is copper used to remove solder. It basically absorbs the solder once you heat both the copper and the solder joint. What does flux do? I’m not a scientist, but applying flux on the solder joint where you place the wick will help the copper suck up that solder. I have some wick from RadioShack (RIP, I miss that place), but I’m sure that any brand works for the most part. I also know that flux comes in pens or jars that remind me of petroleum jelly, but I use the one that comes in the jar. Either works as well!

Do you absolutely need flux? No, but flux is extremely handy to have, isn’t expensive, and lasts a long time, so I recommend making it easier on yourself and picking up flux if you’re also wanting to pick up wick. What you’ll do is apply the flux to whatever area(s) that have solder that you want to remove, place the copper on said flux and solder joint, and then place your soldering iron on top of the wick. I don’t use a higher temperature than my soldering temperature (versus a tad higher if using a pump or gun), and you should see the solder and flux get sucked up and the copper wick turn silver with the solder.

Start At 23:37 You may want to get Kimwipes or something similar to remove the residue, but it’s a pretty simple process and helped me desolder both G710+ boards which used lead-free solder. Lead-Free Solder & Adding Solder To Desolder I live in the US, and leaded solder is easily accessible, so when I solder, I use leaded solder (with a fume extractor and also making sure I’m in a well-ventilated area). When desoldering most boards, I also desolder leaded solder, however, when it comes to OEMs like the G710+ that I was talking about, those boards tend to use lead-free solder. If you live in a country where unleaded solder isn’t as common, you’ll also be faced with having to desolder lead-free solder. I won’t pretend to have a lot of experience with lead-free solder, so I’m more than happy to admit that I’m wrong, but you can still desolder lead-free solder - you just need to use a higher temperature. Having to balance having a high enough temperature to melt that lead-free solder while not burning or lifting a pad can be tricky, which is why I like to use flux and wick. If you are having trouble in general, something that I’ve found useful was to actually add leaded solder onto the lead-free solder joint before desoldering it. That’s also a great method to use, even if you don’t deal with lead-free solder. Adding more solder may sound counterintuitive, especially because you’re trying to desolder, but it can help the pump, gun, or wick to suck up the solder when faced with a difficult solder joint. Mill-Max

So, you’ve learned how to solder, and are now pretty comfortable with doing so, and you also picked up the skill of desoldering, and you’re feeling pretty good about yourself and want to challenge yourself one last time. I hear you, and that’s exactly what my journey was like. I knew I wanted to try my hand at what people referred to as Mill-Maxing. Now, Mill-Max is just the name of a company in the US, but it’s kind of been synonymous with what the actual term is just like how Kleenex is to tissues or how band-aids are to bandages. There are other brands such as Holtite, but I’m just going to refer to this entire category of soldering sockets into solderable PCBs as Mill-Maxing. I’ve also never used Holtite sockets and have only used Mill-Max sockets, so I can’t really speak on what is better (or if there are other brands out there that also have sockets for solderable PCBs). What I’m talking about are soldering sockets into solderable PCBs where you usually would just solder switch pins. Then, after soldering said sockets, you can basically treat your PCB as a hotswap type of PCB with the ability to swap switches in and out.

But why not just solder Kailh hotswap sockets or other types of hotswap sockets into the solderable PCB?

Hotswap sockets actually require a specific PCB design that supports hotswap socket soldering, which isn’t as common as solderable PCBs that are compatible with Mill-Max sockets. Not every board supports Mill-Max sockets, like some OEM boards, but generally, more PCBs nowadays support Mill-Max sockets versus hotswap socket soldering. Some reasons why someone may want to Mill-Max their PCB are as follows: Maybe a board only offers solderable PCB options, yet the individual wants to use their PCB in a hotswap fashion and have the ability to change switches versus soldering and desoldering switches when they want to try different ones.

Another reason could be that the solderable PCB provides layout support that isn’t found on a hotswap PCB, so, they resort to buying the solderable PCB and Mill-Maxing it.

Eclipse60 Solder PCB Layout

What are some cons to Mill-Max?

Well, it obviously costs more since you have to buy sockets. Some cases also have super tight tolerances where the Mill-Max socket may scrape the bottom of the case, and/or they won’t allow the case to close as Mill-Max socket “tails” are longer than switch pins when normally soldering in switches. Another con is that if you mess up Mill-Maxing, it could damage your PCB, switch, or socket, and in general, you have to be a bit more careful when Mill-Maxing and it takes more time to do so. If solder gets into the socket itself, the socket may no longer work. A third con is that there may be perceptible sound and feel differences as compared to hotswap or just straight-up soldering. Since the switch isn’t sitting directly onto the PCB, even if you use a Mill-Max socket with a low lip, there still may be a difference in both sound and feel when compared to hotswap or soldered builds. Honestly, Unless you’re a huge stickler for sound and/or feel, I don’t think this is AS big of a con, but I do want to bring it up. If you want to determine if this is a deal-breaker, I suggest you watch KeyBonbon/Christian’s sound test video on the differences in sound as well as research on your own.

I also want to bring up the fact that some switches have wider/fatter switch pins than others, resulting in a switch possibly not fitting into the socket, or you having a super hard time removing it once installed into a socket. However, with all that being said, I think it’s super useful to know how to Mill-Max just because it adds another tool to your toolbelt.

From KEEBD's guide (awesome guide!) Let’s talk about the anatomy of a Mill-Max socket. You’ve got the lip, which sits on top of the PCB, and then you’ve got the tail, which sticks out on the other side of the PCB. There are also different types of Mill-Max sockets. You’ve got the 7305s, which have a shorter tail and lip, which may be a bit more difficult to prevent solder from getting into the socket since they’re shorter. These used to be the most expensive types of sockets.

Courtesy Of Mech.Land You’ve got the 0305s, which have a longer tail and lip, which can be better at preventing solder from getting into the socket, these are the cheapest, but as I stated earlier, since they’re longer, they may not be compatible with cases that have tight tolerances between the bottom of the PCB and bottom case, and then you’ve got the 3305s, which kind of combine the two. Not as long of a tail as the 0305s, a shorter lip than the 7305s, but these are the most expensive.

Keebio's Guide (Also Awesome) Depending on your case and what you’re aiming to do, each has its own pros and cons. I’ve only specifically used 3305s, but that doesn’t mean that they’re the “best” at everything. Remember, make sure you have enough clearance between the PCB and case before buying any of the three, and make sure you buy enough. Don’t just buy the exact amount needed for each switch leg hole, buy some more in the event that you make a mistake.

I’ve also seen and heard people stating to use thinner diameter solder as well as a thinner soldering tip to prevent accidentally getting solder into a socket as well. That definitely makes sense, and perhaps I also would’ve done that if I had not been soldering for a while since learning how to Mill-Max, but when starting, I did just fine with my chisel tip and normal Kester solder that I use for everything by going slowly. Now, this does NOT mean that I’m doing the most optimal thing, and I totally understand. It’s just that I haven’t had an issue with using a normal diameter solder and normal soldering iron tip. That doesn’t mean you won’t run into issues, it’s just something to consider (the fact that people advise to use a thinner solder and soldering iron). Recently, I have switched to a thinner diameter solder and smaller chisel tip, but only because I was at my friend’s house without my normal solder or tip and used both her thinner diameter solder and thinner chisel tip. It worked well! Honestly, you can go either way, and using thinner diameter solder may help avoid solder splatter getting into the socket and onto the PCB in general, but you’ll have to decide whether it’s worthwhile to have two spools of solder, both when it comes to money and when it comes to accessibility (maybe you can only get one diameter of wire for example). When it comes to desoldering the sockets, I recommend flux and wick, although Christian/KeyBonbon’s Mill-Max video also shows an alternative method, which I advise you to watch his video in order to figure out which method you want to go with. I can only talk about what I’ve done, and I honestly do not desolder Mill-Max sockets on a regular basis. I’d love to pretend that I’m good at it, or that the flux and wick method or Christian’s method works every single time, but again, I’m being honest and don’t want to mislead you, the reader. If faced with having to desolder Mill-Max sockets or just leaving it be, I leave it be.

When it comes to actually installing the sockets into your PCB and soldering the sockets, there are two methods. The first is to install the sockets directly into the PCB, and then carefully put heat-resistant tape on the other side of the PCB to keep the sockets in place while you solder. Basically, you’re taping the lips to the PCB while you solder the tails on the backside of the PCB.

Start At 5:54

Courtesy of Mecha Store The second is to actually insert your sockets into a switch and then place your switch into the PCB, and then solder the tails on the backside of the PCB. This is the method I use.

Start At 32:00

Both have their pros and cons. The tape method prevents accidentally flooding your socket with solder and getting your switch stuck in the socket if solder gets in. However, you’ll need tape and you’ll need to make sure you’re putting the sockets in the correct spots where you want your layout to be in terms of switches. With areas like the mods and/or other areas where there are multiple holes, you may be confused about where to place your sockets. I suggest sticking a switch into where you want your layout to be to figure out where to place and tape down your sockets. The switch method eliminates the need to use tape, however, you could absolutely lose a switch in the event that solder gets into the socket. You could theoretically just use random/cheap switches instead of the actual switches you’ll use with the Mill-Max sockets though. In the end, both methods have their merits, and it’s up to you to decide which you like more. Conclusion Even though this article was slightly longer than intended, I’m sure that I left some things out. However, I believe that this is a good guide to have a look-through, and hopefully, helpful! I really think that learning to desolder (and eventually Mill-Max) is super useful, not just in our hobby, but in general. I helped my dad desolder some old circuit boards the other day, and I actually helped solder a part of his car months ago as well, which goes to show how soldering itself is a useful skill to have (on top of what StoryboardTech went over in his amazing guide).

The bottom line is that it can be challenging, and may take some time to get comfortable with, but if you are determined to learn both desoldering and Mill-Maxing, your board options in our keyboard hobby open up, and you can also pass on the knowledge you’ve learned to others. Giving back and passing it forward is what makes this hobby and our community great, and I hope that I’ve done that with this article. Please leave any questions or comments you have below or message me on Discord (HubertTheMad#0073), and I look forward to all you new desolderers and Mill-Maxers successfully doing both and sharing your stories! Thanks for reading, I love you all, and catch you next time.

(Edited)

100% upvoted

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Jan 14, 2025

Dude. That's intense! Well written fever dream bathed in solder smoke. Love it. Also, I know where to go when I'm ready to watch some mill maxing videos!

HubertTheMad

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Keyboard Club Member

Jan 14, 2025

storyboardtechHahaha, I wonder how much solder fumes I've inhaled! I appreciate it, and I'm glad I had some old (and a tad embarrassing) footage to use in this article.

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