Surface mount soldering is one of those maker skills I feel like I should break down and learn, but I never do. It’s intimidating to think of working at such a tiny scale, and it has always seemed so expensive to get into, with microscopes, expensive irons, reflow workstations and ovens, and the like.
In the latest installed of Collin’s Lab over at Adafruit, Collin Cunningham details a number of very easy methods for doing basic surface mount work. To get started, besides the normal tools and materials you would use for through-hole components (solder, sucker, iron with fine point tip), all you really need to get started are some fine tweezers and some form of magnification.
There are some really good tips in this video. Many of them are basic to anyone who already knows surface mount, but very helpful to those just getting started. Here are a few:
- The keys to successful surface mount soldering are magnification and patience.
- Use painter’s tape, instead of a PCB holder, to secure your PCB to your work bench.
- When populating a PCB with components, start with the smallest components and work your way up to the largest.
- To properly align chips with many pins, pre-tin a pad, anchor the chip to that pad, check pin alignment and then re-wet and adjust as needed to make sure all of the pins and pads are aligned.
The most eye-opening tip on this video is his intentional bridging of pins on the ICs as a way of easily flowing solder to them. After anchoring the chip by soldering a couple of diagonal pins, he flows the solder across all of the pins on one side of the chip (see first image below). With this done on all sides, you can use a solder sucker tool or solder wick (second image below) to remove the solder on top of the pins that is bridging (and shorting out) the connections. But over-soldering and de-soldering like this, then checking for bridges with a loop, and ensuring you still have good solder contact between each of the pins and pads, you can fairly quickly solder many-pinned surface mount chips without too much trouble.
You can see all of the Adafruit era Collin’s Lab videos here. You can also see the original series he did for Make: as well as check out his Circuit Skills series and the MAKE Presents: videos, which introduce basic electronics components and tools.