Thanks, a web search was educational. Although one or two sources show
only a single melting/solidifying temperature of 179 degrees C for
62Sn/36Pb/2Ag solder, others show a 10 degree C pasty range, with solid
and liquid temperatures of 179 and 189 degrees respectively. This range
is a bit wider than for, say, 60/40 solder which has an 8 degree range.
This would be a disadvantage (probably a minor one) to using the
silver-loaded solder.

I found two different sets of data for strength:

Tensile PSI Shear PSI
63/37 7500 6200
32/36/2 7000 7540

and

Tensile PSI Shear PSI
63/37 7600 5400
32/36/2 8600 6600

So it does appear that the silver-loaded solder has higher shear
strength, and might have greater or less tensile strength, than unloaded
solder. Despite the different numbers, both sources agree that the shear
strength increase is about 22%. I wouldn't call that a "very LARGE
amount" of difference, but that's certainly a matter of opinion.

Perhaps some people will find that the considerably greater expense,
reduced availability, and non-eutectic behavior of silver-loaded solder
is worth the modest increase (my opinion of 22% greater) in shear
strength. But I doubt that many will. I keep a small quantity on hand
for soldering SMD parts which have silver or gold terminations, but am
satisfied with 63/37 for everything else.

Roy Lewallen, W7EL


RST Engineering wrote:
Yes. This little addition of silver adds a very LARGE amount of strength to
the joint. PLEASE don't ask me to climb up to the top shelf to give you
numbers.... {;-)

Jim



Is there some other advantage of a 2 or 3% silver addition?

Roy Lewallen, W7EL