but it is my first working lead-free, SMT soldered circuit. I have two SoftRock Ensemble RXTX radios to build, and I thought it would be better to melt a $10 trainer kit than a $100 radio. It works as expected, though I wouldn’t describe the red/green LED’s insane flickering to be â€œan attractive and functional SMD dual color LED flasherâ€.
Flux is your friend here. I tried Chaney’s recommended method of supergluing components on the board, but that didn’t work. What ended up best was applying flux to all the pads, supplying the thinnest layer of solder possible, refluxing the pads, then flowing on the components. A steady hand, a magnifier, tiny (Â½mm) solder, good tweezers and a pointy soldering iron helps. Some kind of fume extraction is good, too, as Pb-free flux is a tad acrid.
I don’t miss eutectic leaded solder. Sure, it’s easy to use, and it’s got a kind of magical quality that it’s below the melting point of either lead or tin. But Sn-Ag solder is toxic enough, and I don’t need to dump more lead in the world.