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CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 1994
Posted: 11:22pm 12 Aug 2017
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interesting section of the following vid concerning Tin (Sn)
jump to about 5:35 for the solder thingie
https://www.youtube.com/watch?v=Q9zdt-rOB0Y
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1399
Posted: 12:55am 13 Aug 2017
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This reminds me of a major problem going back over 35 years when I was repairing some of the first equipment with micro helical resonators and PPL modules in Radios transceivers. Took a few months before we realised the problem of microscopic crystalline wires growing in the modules.
It's all too hard. Mike.
paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329
Posted: 03:40am 13 Aug 2017
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Hmmm, takes me back to my early metallurgy degree days (started 1966 ). That phase change and dendritic crystal growth was a standard demonstration. Worse was being in the metallography lab having to polish a tin specimen and get it largely scratch free under the microscope - pretty much impossible!
Greg
Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664
Posted: 12:17pm 13 Aug 2017
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Really interesting when you've grown up with a grandfather that spent 60 years a mining engineer & Tin Miner.
Remember many instances of grading & bagging refined tin & a couple of occasions which involved actually smelting it into ingots.
Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9081
Posted: 01:18pm 13 Aug 2017
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I still prefer leaded solder. The whole lead-free solder thing is a bit of a red-herring if you ask me - and you didn't
While I do acknowledge the dangers of lead etc, when you look at the amount of actual lead on a soldered PCB or in a roll of solder, it is nothing to be concerned about IMHO.
Again, this is just MY opinion - others more in the know feel free to correct my understanding there.
The amount of trouble I have had with lead-free solder, I don't bother with it anymore. Neither in solder-wire form, or in solder-paste form. Both wire and paste that I use are leaded.
Lead-free solder or paste requires much more heat to make it flow too, which puts many components under much more heat-stress then they need with leaded solder or paste.
And cos there is no lead in there to keep the solder "Soft", dry-joints on factory produced boards using lead-free are rampant, cos if stressed at all, the join just fractures - you end up going over the whole board wetting the solder with leaded stuff anyway, which is all a complete waste of time had they just used leaded solder in the first place.
Leaded solder suffers from dry-joints too, but I find the lead-free stuff even worse for dry joints then the leaded stuff based on what I have seen so far.
But this is progress, right.......Smoke makes things work. When the smoke gets out, it stops!
Tinine Guru Joined: 30/03/2016 Location: United KingdomPosts: 1646
Posted: 09:57am 15 Aug 2017
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Where are you UK-based guys buying leaded solder?
CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 1994
Posted: 10:14am 15 Aug 2017
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still using stocks from years ago. Got a couple of 1KG rolls yet to start - reckon it will see me out
paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329
Posted: 01:15am 16 Aug 2017
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Was that in Tasmania Phil? I spent some time on one of the tin dredges up near Derby (in Tas). It was a lot of fun - watching all the ore-dressing separation processes was quite fascinating (for a budding metallurgist ) My mate's grandfather had a 'show' at Sth. Mt. Cameron and used to disappear up there for a week or two at times, then come back with a few bags of 'tin' (cassiterite of course) that we were not allowed to touch - we were little guys back then. I think he really just enjoyed the break from his 'good lady' - he was tough but no match for her!
Grogs - totally agree about Pb-free being a pain and I certainly don't use it. But I guess if you were one of those production line girls in China soldering away all day long and dodging Pb fumes you might feel differently. Whenever I see a bit of video of mountains of e-waste I must say I feel a bit that way too. Governments certainly have a responsibility to do something about Pb pollution but on the small scale most of us work with, I don't think it's an issue. High production consumer electronics companies should have to use Pb-free IMHO.
Greg
piclover Senior Member Joined: 14/06/2015 Location: FrancePosts: 134
Posted: 05:19am 16 Aug 2017
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@Grogster
I totally agree with your views on "lead-free" solder: it's a total PITA, and does "lead" (pun intended) to many troubles with home-made projects.
As for where to find the good old Sn/Pb rolls, I bought some, last time, from Selectronic... before they closed. It looks like Farnell/Element14 is still stocking a lot of different models of Sn/Pb[/Cu][/Ag] rolls as well. They are often listed as "for repair" by retailers, since old electronic boards must be repaired with a compatible solder...
Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9081
Posted: 01:28pm 16 Aug 2017
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Element-14, Farnell, Jaycar, Altronics - any of the electronic hobbyist shops will also usually still stock 60/40 leaded solder.
One word of caution: Stay away from cheap rolls on eBay or Aliexpress IMHO, as they tend to be absolute rubbish and make soldering very difficult - if it can be done at all with those rolls. Stick to a known distributor where you will get what you pay for. More expensive then eBay certainly, but quality stuff.Smoke makes things work. When the smoke gets out, it stops!
Tinine Guru Joined: 30/03/2016 Location: United KingdomPosts: 1646
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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). That phase change and dendritic crystal growth was a standard demonstration. Worse was being in the metallography lab having to polish a tin specimen and get it largely scratch free under the microscope - pretty much impossible!
) My mate's grandfather had a 'show' at Sth. Mt. Cameron and used to disappear up there for a week or two at times, then come back with a few bags of 'tin' (cassiterite of course) that we were not allowed to touch - we were little guys back then. I think he really just enjoyed the break from his 'good lady' - he was tough but no match for her!