Eutectic alloying is a fascinating effect - a metal like lead melting at 621.4°F is mixed with tin melting at 449.5°F and the resulting melting point is even lower at 361.4°F. There is no paste phase as with non-eutectic mixtures. For electronics it is a great idea to use a eutectic solder alloy. An vibration experienced by a non eutectic alloy while in the intermediate phase of freezing will really mess up the joint.
You can certainly use other solders at higher melting points but they will be very expensive. Too high and you can reasonably solder small connectors. I f you want to make a deep dive you should learn about eutectic alloys: https://en.wikipedia.org/wiki/Eutectic_system The eutectic Tin/Lead composition is 67 / 33 From https://en.wikipedia.org/wiki/Soldering : Common solder formulations based on tin and lead are listed below. The fraction represent percentage of tin first, then lead, totaling 100%: 63/37: melts at 183 °C (361 °F) ( *eutectic: the only mixture that melts at a point, instead of over a range*) 60/40: melts between 183–190 °C (361–374 °F) 50/50: melts between 183–215 °C (361–419 °F) There is an enormous chart of soldering a brazing alloys and their uses at this wiki page. On Mon, Apr 25, 2016 at 8:23 PM, Chris Tromley via EV <ev@lists.evdl.org> wrote: > On Mon, Apr 25, 2016 at 1:19 PM, Lee Hart via EV <ev@lists.evdl.org> > wrote: > > > Solder is mechanically weak, and has a low melting point. It's fine for > > little low-power stuff, when there is negligible shock and vibration. It > > is, after all, how 99.9% of all electronic connections are made on > circuit > > boards. :-) > > > > But, it's a poor choice for high power, things that get hot, or where > > there is mechanical stress. > > > Excellent advice, and something to keep in mind whenever you get tempted > to use solder for mechanical strength. I've seen it often enough (that is, > seen these applications fail enough) to look into it a bit. Turns out one > of the worst things you can do to a solder joint is mechanically stress it > while also gently thermal cycling it. You don't need to get anywhere near > the solder's softening point (normal operating temps can do it) to get it > to fail quickly by doing this. > > Disclaimer here, which leads to my question. The above applies to your > regular garden-variety lead-tin solder. Does anyone know if it also > applies to lead-free? Time for an RoHS update on old knowledge. > > Chris > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20160425/779fba13/attachment.htm > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Mobile and Google Phone michael.e.r...@gmail.com <michael.e.r...@gmail.com> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20160425/c8ee2768/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
