[Elecraft] Solder

[Ron D'Eau Claire]

I hope we didn't drive you away with the answers, Rob!

Keep in mind that there is NOTHING wrong with the quality and durability of
joints that lead-free solder makes. It's great stuff that works very well.

For hand work there are two important issues that recommend against its use:

1) Lead-free solder melts at a higher temperature than leaded solder. Higher
temperatures mean it's easier to lift a trace or damage a solder pad if you
change a part. Of course, a higher iron temperature is needed during
assembly too. Many builders are already skittish about using a high enough
temperature iron already, so the idea of pushing the temperature higher
isn't very welcome. 

2) At least some lead-free solders cool to a nice, dull matte finish:
exactly what we've been taught to recognize as a 'cold solder' joint that is
not reliable. It can be very hard to tell a good joint from a bad joint. 

It simply doesn't seem to make sense to buy into those issues when leaded
solder is readily available and has a century-long history of doing an
excellent job in electronic gear. 

While we're on the subject of solder once again, let me repeat an important
slightly off-topic warning about fluxes! 

AVOID WATER SOLUBLE FLUXES LIKE THE PLAGUE! They are a plague that will ruin
your rig. 

"Water soluble" sounds great. A little water and they're gone. No rosin
mess. But they are a disaster for hand work outside of a special property:
The water-soluble flux remains corrosive at room temperature, just like
acid-core plumber's solder that we've all learned to avoid in electronics.
(Rosin is inert below the temperature at which solder melts.) Joints
soldered with the water soluble flux must be "power washed" in a special
machine to remove all traces of the flux immediately after soldering.
Failure to do so will result in your rig becoming intermittent in a few
months as the flux literally eats its way through the traces on the boards.
The boards will be a total loss. 

Ron AC7AC

-----Original Message-----
Ok,
The point is well taken. I will use only my standard Pb/Sn for the K2 and
save the Pb-free stuff for a few specialty projects. Thanks for your input.
(This was my first question to the group - thanks for your input). 73 Rob
KC6ROC _______________________________________________