On 6/24/10 12:48 PM, Keith M wrote: Generally, I'd go with as fine a tip as you can, though there are other SMT techniques (see "dragging") that would require a wider tip. The third tip down on that page looks like a good place to start, or perhaps the second. That's about right. There are a number of things to be aware of here, but they're roughly the same things that apply to through-hole soldering. First, lots of people assume that they should err on the side of lower heat to avoid component damage. But if you think about it, if you use lower heat you'll typically need to hold the iron on the joint for a longer time. You want to use a nice hot iron to get the joints done in as short a time as is practical. Don't obsess over it, but just get the joint nicely flowed and remove the heat. The composition of your solder and flux are also factors to consider. As a data point, I'm currently using a Metcal SP-200 iron with an SSC-645A tip, 600F/0.4mm tip diameter. 63/37 is good. I use 0.010" solder...I don't think I've ever tried 0.015", but I think you should be fine. This is largely a matter of preference, and my preference is a flux pen. They work very well, don't spill, give you a controlled flow of liquid to avoid messes, and are generally convenient to use. The last time I tried a flux syringe I ended up making a big mess. With the pen, just dab-dab-dab along one side of an SMT IC, and you're ready to roll. Get a ring-light magnifier on an articulated arm. These can be had for <$40 brand new via eBay. You will need tweezers...I am particularly fond of Erem AASA and 5SA-EROP tweezers, available from Mouser for about $7 or so. Protect the tips. You will also need some fine solder wick. Another important thing to remember: Remember how sensitive through-hole soldering is to finger print grease? SMT soldering is even more so. I always wash my hands with soap before soldering, and I try to minimize touching solder pads. Like the matter of component heating, don't obsess over it, hold where you need to hold, but if you can avoid touching a pad at a particular moment, do so. If you need to stop and clean the board, a Q-tip dipped in alcohol works well, just watch for fiber turds. -Dave -- Dave McGuire Port Charlotte, FL