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Surface mount and micro soldering tools and techniques.

Summary

Modern electronic gadgets of all sorts tend to make use of surface mount techniques, where components are soldered onto the surface of a circuit board, rather than with leads passing through holes in the board and soldered on the other side ("through-hole" construction). Surface mount devices are generally smaller, often much smaller than their through-hole counterparts, making repair much harder. Nevertheless, much is still possible, as described here.

Safety

Take care with a soldering iron - it can give you a nasty burn. Avoid breathing fumes from flux or from any adjacent plastic which might get overheated.

Tools required

For serious surface mount work a proper surface mount solder station is essential. This will include a fin tipped soldering iron, a hot air soldering tool, and ideally a pair of soldering tweezers, and will cost a 3 figure sum. But if you can't justify that, you can do a lot by supplementing the tools you probably already have with just a few more, at a very modest cost. The following is a minimum:

• Soldering iron with a 1mm bit. All but the cheapest irons have interchangeable bits, and you can probably get a 1mm bit for the iron you already have. But it needs to be a small soldering iron which you can manipulate more like a pencil than a crowbar.
• Thin solder - 22SWG (which is 0.028in or 0.711mm) or thinner.
• A solder flux pen.
• A magnifying glass and/or close working glasses.
• Fine tweezers.

For normal work, people may tell you that you don't need flux as solder has flux in it. In fact it only has a minimum which is insufficient for surface mount work.

If your eyes can focus at 20cm (8in) then you ill still need a magnifying glass for inspection. One that usually comes included with a "helping hand" will do.

If not, get yourself a cheap pair of "ready specs". Test the ones on display in many shops, and find ones that allow you to focus at a distance of 20cm. If you have needed reading glasses with only a simple prescription for some years (minimal astigmatism or difference between the eyes) then a strength of 3.5 dioptres will be about right.

Additionally, if your near vision is no longer as good as it used to be a jeweller's eye loupe is well worth getting. After a little practice holding it in your eye socket you will find it invaluable for close inspection.

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