Provided you have good eyesight and steady hands, I've mostly found what happens as you get smaller is:
- Heating becomes easier. There's no large sinks to take the heat away. It's also easier to overheat things.
- You need finer tweezers, and don't drop them because if you do the tips will bend.
- The solder's surface tension does more of the work. It feels a lot more like sticking together things with tiny droplets of glue. Having the correct amount of solder in the right place is critical.
- Solder and flux become two separate things you have to care about individually
- It is easier to burn yourself
- learning how to brace your hand against something in a way that gives you very fine control. One reason soldering with an iron can be difficult is because your hand is so far away from the tip, like trying to write with a pen held by the end.
When I started my first job a coworker encouraged me to learn how to solder SMDs and do "microsoldering". Like most people I thought I was going to need high precision and a much steadier hand. Probably like most people that learned I was impressed at how quick I picked it up. I think the hardest thing was learning about part "tombstoning" but that's not that difficult to deal with. I'm not going to say it is easier than soldering through-hole components, but I think for most people the mental barrier is much higher than the actual barrier.
I now highly recommend learning it to anyone doing electronics. It's well worth the (small) time investment and makes things a lot easier, opening lots of doors. Even for a hobbyist you immediately get benefits. Everything becomes more compact, 2 sided boards are much more usable, and, of course, it opens up a lot of repairability (and recycling. Are you really a hobbyist if you aren't desoldering and reclaiming parts?).
> Are you really a hobbyist if you aren't desoldering and reclaiming parts?
Fun memory from who-knows-how-many years ago:
While installing a Playstation mod chip, I accidentally dislodged a nearby surface mount resistor, pulling off one of its metal contacts in the process. (Is that what happens when you overheat them?) I didn't think that was fixable, and since it was Sunday, the local electronics shop was closed. I ended up disassembling an old junk digital camera that hadn't yet been taken to the e-waste recycling drop, and finding inside it a resistor that seemed close enough to maybe work. The transplant was a success, and the Playstation ran great thereafter. Very satisfying.
I recently got rid of a lot of components that I have salvaged and hoarded over the years. If I need a doodad for something I'll just buy it. I'm done storing all this junk I will never use
Agree that SMD hand assembly is easier than it looks, at least down to 0603 imperial. If I can wait the week for boards to arrive, I’ll often skip the breadboard step and go straight to a proto PCB, especially since most parts aren’t available in throughhole without waiting on dev boards anyway.
When you hand someone a board with 0603s on it that you hand-assembled, it seems like magic to people who stop to think about it.
It's worth noting that the longest one there is already much shorter than the classic mid-century unregulated irons, and all of those can be held like a pencil.
> The solder's surface tension does more of the work. It feels a lot more like sticking together things with tiny droplets of glue. Having the correct amount of solder in the right place is critical.
I believe this is why I have an easier time hand-soldering BGA than QF[np]: I can't screw up solder amount/evenness.
What tools do you use for BGA soldering? I’ve seen people (well, dosdude1) using board preheaters and hot air stations, but I could never justify the expense for the amount of board rework I actually do.
I have Chinese hot air station and I am super happy with it. Airflow is nice, temperature constant. Simple manual control. The device has writing 998D on it. This device also has soldering iron attached, but it is very bad, does not have enough power for usual soldering tasks.
Important caveat: The downside to this is you can't inspect it (without an x-ray machine), and if you screw up, you're going to need a new chip (Re-balling does not look approachable/time-efficient)
Thank makes sense, thank you! Is there a rule of thumb for how high you set the hot plate? I’d be worried about SMD components on the side in contact with the hotplate.
You're right that that is a concern. I think I set mine for 190C? Don't remember. But as you infer, my goal is to get it slightly below melting temperature so the the other components' solder doesn't melt. (Disaster if they do, then the board gets jostled or you knock a component with tweezers). Then when you hit it with the air, just that component melts.
Also, it seems to not melt if you don't flux the pads prior. Not really sure why.
How are you burning yourself? I've only ever worked with one person who burned himself soldering when working on a SMT PCBs, and it was while desoldering a through-hole connector, when a desoldering station was long past its cleaning interval and it dripped some solder onto a metal ring he was wearing. This was a guy who would lick a soldering iron to see if it was hot and touch the molten solder in the wave solder machine. The Leidenfrost effect goes a long way.
I do a lot of soldering at my day job to bodge boards, tune networks, etc. I burn myself on the time because when I'm working through the microscope I seemingly forget I have hands or lose track of them and bump the iron into them when pulling it away from the work. Not sure why, but it's really easy for me to get into this mode where the view through the scope is the only thing in the world
The display controller they are using (RA8875 or RA8889) has several hundred KB of internal memory. So you can write to the screen and the image will "stay there" as it were, you don't have to store a framebuffer or keep writing out the image like with a CRT.
I don't think it should be obvious. If you could measure spectra, that would tell you that starlight and sunlight are the same, but you could still think they were very tiny suns that were near. You would need to measure parallax to know they were far away. Neither of these are possible without precision technology, though you could probably argue that it could have been done in ancient times with enough effort.
Maybe if the solar system had more than one star, or there were other stars very close, people would have caught on a lot quicker.
This is so true. There is an awesome Terry Tao / 3blue1brown collaboration that explicates the epistemological basis: Terence Tao on the cosmic distance ladder
Depending on how dark your room is you might get by with an ordinary but bright LCD screen and a camera lens. There's a pretty common 240x240px, 1-inch square TFT display on amazon or other usual places you might start with.
I remember doing this too, a little bit later. It would churn on the disk for minutes on end, and usually fail. I think I got it to work once or twice.
Floppy disks and drives were plentiful, but scrap in those days. So of course those were the machines I got to play with as a kid at that time. Many of my disks were not in the best condition, or they were some of the post-2000s ones that were low quality to begin with.
I remember people were making various editions of "mini windows" 3.11 on a floppy disk around that time also.
Reminds me of the 2-hole "snake eye" or "pig nose" screw heads you sometimes see in bathrooms or elevators. I have several of the bits for these since they come with every one of those n>20 -piece screwdriver bit sets, but I've never actually had to undo one. I guess that goes for most of the oddball bits those sets come with.
If they really wanted to screw (pun, sorry) with repairability (and at significant cost to themselves), I guess they could start making their own taps and dies for nonstandard threads you can't buy anywhere else. Wouldn't stop them from being unscrewed, though.
There are many non-standard screw diameters and threads. They are often implemented for particular requirement-driven (you may want deeper threads to increase strength or vibration-resistance) or regulatory reasons (certain tariffs kick-in at specific screw diameters).
- Heating becomes easier. There's no large sinks to take the heat away. It's also easier to overheat things.
- You need finer tweezers, and don't drop them because if you do the tips will bend.
- The solder's surface tension does more of the work. It feels a lot more like sticking together things with tiny droplets of glue. Having the correct amount of solder in the right place is critical.
- Solder and flux become two separate things you have to care about individually
- It is easier to burn yourself
- learning how to brace your hand against something in a way that gives you very fine control. One reason soldering with an iron can be difficult is because your hand is so far away from the tip, like trying to write with a pen held by the end.
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