[geoff]

On 5/02/2018 6:35 PM, Phil Allison 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 ?


** When replacing components, it is easy enough to clean up the old Pb free solder and use fresh 60/40 to get a shiny and reliable joint. Same goes for cracked solder work that plagues so much gear theses days.

Short of abrading off the pads with a glass-fibre scratcy-brush-pencil
thingy (don't ya hate those invisible shards that stick in yer fingers
?), always will be a remaining tinning of whatever came first.

And wires already tinned with Pb-free and too short to snip and re-tin ?
Or if just too lazy ?



What are the implications
of a blend of lead-free and leaded solder, electrically, physically, and
chemically ?


** Unknowable, cos you never know Pb free alloy was used on the PCB - makers should all be forced to label PCBs with that info.

However, when the result looks dull and crystalline, it is a poor quality joint.

Just like Pb-free at the best of times ....

geoff