I know this is getting off topic, but one more comment from me. Solder flux is really important. I use nothing but "no clean" type for SMT work -- very thin 0.015 no-clean solder (63/37 PbSn while I still can), and a bottle of liquid no-clean flux with a needle dispenser. I make sure the work is wet with flux before I start, and add as needed.
Note that "no clean" isn't strictly that -- it leaves a residue, but it is supposedly non-conductive and doesn't *need* to be removed. But for aesthetics, when I'm finished I dip the board into a bath of isopropyl alcohol and apply a toothbrush. Sometimes after that a distilled water rinse is good if you're a perfectionist. If nothing else, the cleaning makes inspection easier. (But use care... some components, like the uBlox GPS modules, warn against immersion in any kind of liquid.) John ---- On 4/25/20 12:00 PM, Burt I. Weiner wrote: > John, > > What you and I do for SMT type IC's is pretty much the same. > > Several years ago the wife of a close friend was in the re-work business > with a home setup. What she taught me was to first line up one of the > corner pins and tack solder it down. Then do the opposite corner, > center the pin and tack solder it down. Do that with all four corners, > taking care that the pins are properly centered before tack soldering > them. Once you've got the four corners properly in places, then go and > center the remaining pins; depending on the size of the chip, this might > require either a microscope or very pointy eyes. Once all the pins are > properly centered, flow solder over all the pins. At this point > shorting all the pins together is not a problem. > > Once you've flowed soldered across all of the pins you need to slurp up > all of the solder with a fine pitch SolderWick. If done correctly you > will wind up with all of the pins properly soldered and centered. The > next step is to remove and flux using Denatured Alcohol. Once that's > completed, inspect for any possible shorts or pins in the wrong place. > If all looks good, cover your eyes and power it up. > > I have done the above one time on my own and to my utter amazement it > worked! > > Burt, K6OQK > > > At 04:41 AM 4/25/2020, you wrote: >> I do have a microscope (cheap Chinese unit, maybe $400 with >> articulated arm and the works) and it does make things much easier. >> But as long as you can see the work, you can do the job. It's not that >> hard to do small pitch parts. I usually do the best I can soldering >> individual pins, knowing their will be bridges, then clean up with >> solder wick and *lots* of no-clean flux. You can never have too much >> flux. I've found a 1.6 mm chisel tip is a good all around size for >> SMD work, though I have a 0.8 mm chisel available for when things get >> tight. The hardest part is getting the first couple of pins tacked >> down so the part is square on the pads > > Burt I. Weiner Associates > Broadcast Technical Services > Glendale, California U.S.A. > b...@att.net > K6OQK > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.