Lead-free soldering (by alaric)
In the UK right now, just about every electronic component, PCB, or whatnot is being labelled RoHS Compliant.
In particular, this means that Maplin, the only local place I can just drive to to pick up electronic components and tools, is now only selling lead-free solder.
So I've been thinking for some time that I'm going to have to switch over to using this stuff for my own electronics assembly, but from my previous experience of hard-soldering from a metalwork perspective, I suspected this would involve more than just using a new roll of solder; there'd be different temperatures, and different behaviour of the solder itself, and I suspected I'd need new soldering iron bits - because the traces of lead on my current ones would probably poison joints made with a lead-free solder and make them fall to bits.
So when I dropped into Maplin yesterday, I picked up a reel of lead-free solder, with the intent of having a play with it at some point. When I got home, I did some research.
To my surprise, it seems that the lead-free requirement of RoHS is subject to some criticism - because the lead-free solders require higher temperatures, using them puts higher strain on components during soldering, meaning potential reliability problems for the resulting devices. On top of that, the solder joints are less pliable than lead-based ones, also opening new potential for reliability issues. And, lastly, the alloys may be prone to tin whiskering, which could bridge to adjacent tracks and cause even more reliability problems. So much so that 'reliability-critical' products such as life support equipment, servers, and network infrastructure gear is exempt from the lead-free requirements for the time being.
This is alarming.
Anyway, I continued my research and found this excellent document:
It at least confirmed my worries that I shouldn't let any lead contamination into my lead-free joints; I'm going to need some new soldering iron bits. And, judging from the temperature differences, I'll need a better soldering iron; I have a cheap temperature-controlled unit, but with a higher temperature required, more accurate temperature control and more power will mean less heat strain on components, since I'll be able to do joints more quickly, resulting in less actual heat transferred.
Electronics | alaric | 
Thu 7th Sep 2006 9:36 am
Subscribe
By sarah, Thu 7th Sep 2006 @ 12:05 pm
Couldn't we find a lead solder supplier and order loads in for the future or is it that anything we make for cutomers now has to be lead free? - surely the lead isnt a problem in proper ventilated areas with a filtered mask?
If you can't and need a new iron can I have the old one for pyrography? Please?
By alaric, Thu 7th Sep 2006 @ 12:17 pm
Lead solder will still be available, since some kinds of equipment are exempt from the requirements - and lead solder is still needed to repair existing lead-soldered things 🙂
Lead-free solder is MORE hazardous to solder with, since the flux used is 'nastier', and it's the flux that generates the fumes when soldering.
I already have some spare soldering irons you can have 🙂
By sarah, Thu 7th Sep 2006 @ 12:25 pm
If as you say the lead solder is an issue in landfill sites cos the Pb might leach into the water table then surely that is a matter of bad waste disposal and the fact that electronic components are thrown away weather they are any good or not!
It seems stupid to make things less reliable so the will break more and make more rubbish to fill up the landfills and to waste rear metals and things in reather than jmust sorting the waste so that something 'proper' happens to the eletrical stuff.
I know that recycling these things can be hard but I'm sure that more of it can be reused than is plus if it was a consideration in the first place perhape the larger things would be made more 'repairable' in the first place rather than our societies propensity to throw away.
By Charlee, Thu 7th Sep 2006 @ 9:33 pm
Good point, well made. Here here