Hi there,
The following are some of types of solder that I have heard of.
My question is: How to choose which one for a particular job? I mean why there are different types (apart from lead free)? Is each type designed for a particular applications?
The bottomline: how to choose one for just general PCB soldering?
85Sn/15Pb
70 Sn/30Pb
63Sn/37Pb
60 Sn/40Pb
Sn/Ag3.5
Sn/Cu 75
Sn/Ag4.0/Cu.5
Sn/Ag2.5/Cu.8/Sb.5
Sn/Bi3.0/Ag3.0
60/40 Sn/Pb is usual for lead solder. Multticore with rosin flux is best for general use, but the flux should be removed soon after soldering as it becomes difficult to remove if left on boards.
Leon
For leaded boards, I use 63/37 (eutectic) solder. For unleaded, I just curse.
Most people choose solder based on one of two factors.
Liquidous temperature (temperature the solder turns liquid)
Strength
60sn/40pb probably has the lowest melting temperature of all solders.
63sn/37pb is nice because it melts uniformly
85sn/15pb is a harder solder because of the lower lead content and has better electrical properties
Most solder requirements for production are centered around reflow temperature (or wave) and electrical requirements. Higher silver content has better electrical properties.
There is a science behind solder, but most designs do not require a in-depth research of the required solder. Most are pushed toward the lower temperatures because of the IC’s used (in lead free any way).
There are other items not listed here with regards to flux/rosin.
James L