[Don Pearce[_3_]]

On 5 Feb 2018 08:50:37 -0500, (Scott Dorsey) wrote:

Geoff wrote:
I hate lead-free solder and all the stress to components, tools, and PCB
that rework entails when repairing gear.

Ideally I clean off the crappy stuff as best possible, and re-solder
with regular 60/40.

But what if I didn't clean off the lead-free ? What are the implications
of a blend of lead-free and leaded solder, electrically, physically, and
chemically ?

It depends, because all the lead-free formulations are different. But if you
don't get a nice shiny joint, suck it off and do it again.

The 60/40 or 63/37 should be nice and shiny and you can tell that it isn't
crystallized and weak inside from the look of the joint.

The lead-free joints will look dull and you can't really tell if they are good
or not without x-ray inspection.

If the contamination of lead-free stuff into the leaded solder is enough of
a problem, it will cause the joint to look dull.
--scott

It is possible to make a decent joint with lead-free solder, even when
you are gap-filling. This is a seven second video I made for our
factory, showing them how to solder the pin of an F-type connector to
a pcb

https://www.youtube.com/watch?v=F7038fKlO2s

d

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