On Fri, Feb 29, 2008 at 12:36:50PM +0000, ben lipkowitz wrote: > Are you going to use the toaster oven or perhaps the skillet method? > http://www.sparkfun.com/commerce/present.php?p=Reflow%20Skillet
The skillet (or upturned clothes iron) method risks burning the underside of the board, and/or barrel rupture. i.e. The expansion coefficient of the laminate exceeds that of copper, so the "barrel" of vias can separate, losing conectivity between top and bottom layers. On cooling, an intermittent connection results. With lead-free solders, I don't think I'd even attempt it. The current issue of Elektor magazine has a construction article for a temperature controller for using a toaster oven as a reflow oven. The current issue of Silicon Chip has an article in which the natural heating rate of a $30 oven available here in Australia is used to approximate the recommended heating profile. For one-offs, I use a Weller soldering iron tip with a shallow hollow in the bevelled underside. Filled with a blob of solder, it is wiped over a row of IC pins, after having run a thin stripe of paste flux from a syringe. On the first attempt, I had no difficulty soldering the 11 pins on one side of a 44 pin TQFP, in 1 to 1.5 seconds. (i.e. with a single wipe) Tacking two diagonally opposite pins first, with a fine tip, is a simple positioning method. If using a reflow oven, and especially with lead-free solder, then some components might need drying at up to 100°C for a few hours, if they've been lying about for quite a while. Hand soldering is more forgiving in this regard. Having not tried lead-free, I'm keen to hear of any experience, both good and bad. Erik ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
