Organic solder corrosion?

vtl5c3 · Posted: Thu Jan 17, 2013 11:21 am Post subject: Organic solder corrosion?

I've got an embarrassing confession: I found some circuit boards that I'd soldered components on with organic solder and then forgot about them. After cleaning off the residue, the solder joints look really dull, but appear ok otherwise.

Should I leave them alone? Or should I redo them with Organic solder and clean promptly?

mph · Joined: Aug 25, 2007 Posts: 63 Location: France

Hi

I've managed to find an interesting study about "clean" ROHS solder:
http://nepp.nasa.gov/whisker/

Hope that explains a bit your problem.

Cheers

analog_backlash · Posted: Thu Jan 24, 2013 3:06 am Post subject:

That's both interesting and worrying mph!

I'm glad that I've stuck to Pb/Sn solder (which is at present still legal for hobbyists). I was put off RoHS-friendly solder because (a) it's more expensive (especially if it contains Ag), (b) I know people who have to use it in industry and they don't like its flow properties and (c) its higher melting point potentially leading to damage to components. I can now add (d) tin whiskers!

I had heard of these previously whilst researching some ancient transistors that I'd scavenged over the years - notably the AF117, which is particularly notorious for growing whiskers. I hadn't thought about the fact that RoHS-friendly solder might lead to a resurgence of these problems.

This is another case of knee-jerk environmental law which has not been thought through properly. REACH is another, which I would have been up to my neck in had I not lost my last job on medical grounds.

Gary

EDIT:

Sorry about the tone of my post - I was in a bit of a bad mood when I did that Mad

and I might have come across as a raving anti-environmentalist, which I'm not. When I was last running out of solder, I toyed with the idea of buying RoHS solder, but at that time, it was mainly point (b) that put me off.

I think that the major problem with consumer electronics is the way that they are disposed of and the almost instant obsolescence of electronics (or at least the speed at which they go out of fashion Rolling Eyes

). Nothing should go into landfill (crossed-out bin) and electronics recycling should not be banished to countries with lax environmental controls, as it often is at present.

I know that these are ideals that probably won't happen, but I can dream...

Sorry about going off-topic - I'll shut up now.

Gary