Some lead from handling solder passes through skin and lead on hands can be ingested by contact with food. I suspect all old electronics technicians who have had low level exposure to lead are destined to suffer from encephalopathy, like the lighthouse keepers of yore destined to mad hatter's erethism thanks to the mercury floats used for rotating lenses. It's lead free solder for me.
Hi again,
Actually one of the persons behind the cradle-to-cradle concepts in the foreword of their ?? edition of the cradle-to-cradle book writes about this politically instituted switch from leaded to unleaded solder wire in the EU and is slightly apologizing for - apparently - having been quite a decisive factor in this decision. He had not prior to the decision being carried through been aware that there would be issues like whisker formation, etc.
My guess is that since he writes about it there had been quite some negative feedback from the industry about this. And possibly it was a somewhat "rushed" decision that had not taken into account the issues that it may have caused (at that time).
@johnmath: Since you use unleaded solder can you then recommend a solder that works very much "almost" as well as leaded solder? I also would prefer to switch to the unleaded solder but previous experience with very rapid soldering tip deterioration, less that optimal solder wire flow, and the high soldering temperatures have kept me from doing so ...
Since I wanted to make sure that this did not happen I have actually looked into it and have not found sources that indicate that the lead should be absorbed through the skin (in the solder wire form). Do you have some references that say so?
Arrgghhh ... such a super basic, and very, very needed tool (the soldering wire) that just is not so healthy to be around
"Cheers",
Jesper
Actually one of the persons behind the cradle-to-cradle concepts in the foreword of their ?? edition of the cradle-to-cradle book writes about this politically instituted switch from leaded to unleaded solder wire in the EU and is slightly apologizing for - apparently - having been quite a decisive factor in this decision. He had not prior to the decision being carried through been aware that there would be issues like whisker formation, etc.
My guess is that since he writes about it there had been quite some negative feedback from the industry about this. And possibly it was a somewhat "rushed" decision that had not taken into account the issues that it may have caused (at that time).
@johnmath: Since you use unleaded solder can you then recommend a solder that works very much "almost" as well as leaded solder? I also would prefer to switch to the unleaded solder but previous experience with very rapid soldering tip deterioration, less that optimal solder wire flow, and the high soldering temperatures have kept me from doing so ...
Since I wanted to make sure that this did not happen I have actually looked into it and have not found sources that indicate that the lead should be absorbed through the skin (in the solder wire form). Do you have some references that say so?
Arrgghhh ... such a super basic, and very, very needed tool (the soldering wire) that just is not so healthy to be around
"Cheers",
Jesper
The lead free solder I use is a natural rosin core flux PF604-R alloy 227ºC made by Shenmao Technology Inc. Taiwan. This was only the second lead free solder I tried; the first was terrible. I think I have been using the Shenmao one for about 12 years now, with no known problems.
I don't have any problems with wet-ability and its performance seems pretty much normal to me, but I've been using it a long time now and may have forgotten any differences. If I have a particularly difficult substrate to solder, I use a higher temperature and/or use a flux pen to pre-treat the joint. I would probably do the same with lead solder.
I also use Cardas Quad Eutectic (Sn, Pb, Cu, Ag 190º C) mostly for low level connections such as tonearm cabling.
I do find that solder tips do not last as long and I frequently tin the iron tips with CT Tools Tip Tinner which helps prolong the tip life considerably. I try not to leave the soldering iron on when I am not using it.
I do need to use a hotter iron (Weller #7 tips). Most of the work I do is on 1970s vintage professional and consumer audio equipment and the extra heat can be a problem with lifting circuit tracks on older electronics, but it just takes care and experience to overcome.
The US Center for Disease Control warns that lead is absorbed through the skin. Whilst that may be a generally low risk, when working on electronic circuits we often handle solder and draw it across fingers and skin, sometimes leaving a slight trail mark. Given I have spent decades doing this I am sure that I have some accumulated lead as a result.
How Lead Exposures Can Happen | NIOSH | CDC
I don't have any problems with wet-ability and its performance seems pretty much normal to me, but I've been using it a long time now and may have forgotten any differences. If I have a particularly difficult substrate to solder, I use a higher temperature and/or use a flux pen to pre-treat the joint. I would probably do the same with lead solder.
I also use Cardas Quad Eutectic (Sn, Pb, Cu, Ag 190º C) mostly for low level connections such as tonearm cabling.
I do find that solder tips do not last as long and I frequently tin the iron tips with CT Tools Tip Tinner which helps prolong the tip life considerably. I try not to leave the soldering iron on when I am not using it.
I do need to use a hotter iron (Weller #7 tips). Most of the work I do is on 1970s vintage professional and consumer audio equipment and the extra heat can be a problem with lifting circuit tracks on older electronics, but it just takes care and experience to overcome.
The US Center for Disease Control warns that lead is absorbed through the skin. Whilst that may be a generally low risk, when working on electronic circuits we often handle solder and draw it across fingers and skin, sometimes leaving a slight trail mark. Given I have spent decades doing this I am sure that I have some accumulated lead as a result.
How Lead Exposures Can Happen | NIOSH | CDC
I just wash my hands after handling solder, I was tested for blood lead levels about 8 years ago, and despite having handled lead solder for most of my life my lead levels were extremely low. (I started soldering electronics at 7 and I am in my 60s now.)
I've never heard that it is absorbed through the skin and have taken no precautions to prevent it. The primary path I am aware of is through ingestion so washing hands well afterwards seems adequate.
I've never heard that it is absorbed through the skin and have taken no precautions to prevent it. The primary path I am aware of is through ingestion so washing hands well afterwards seems adequate.
I'm in the "started early" category as well. I started around age 6-7. I'm more concerned about all the bromine-based flame retardants (and whatever else) I inhaled from desoldering components from old TVs in my early/mid childhood.
The usual suspects: Mouser, Digikey, etc. If you only need a little bit, Digikey is probably the better option as they have the li'l "cigar tube" packages of solder. I picked up some 62/36/2 (Sn/Pb/Ag) solder from Digikey last week. It was a few bucks for a 1-oz (28 g) package.
Tom
A little bit of the lead can leach out. If you are brave (or foolish) enough to put a piece of the leaded solder in your mouth, you can detect the sweetish taste of the lead after a short time. It's strange that two of the more dangerous metals (lead and beryllium) both taste sweet in soluble form. Beryllium used to be called glucinium, and lead acetate was known as "sugar of lead". What's even more scary is that really dangerous metals like thallium are tasteless in soluble form.
Last edited:
It's scary to consider how this "taste" data was acquired--- which compels me to remember a good friend and colleague, Harry Gould (RIP).
Harry entered college as a Chemistry student. When a lab instructor observed Harry repeatedly tasting reagents despite multiple cautions, he recommended Harry choose a different major, advising that his compulsion might one day be fatal. Chemistry's loss was EE's gain, as Harry became a very creative microwave engineer. I miss him greatly.
Last edited:
It must have been Tom's website where I got introduced to Sn100C. I then tried to find the real deal and it turns out German manufacturer Stannol is licensed by AIM to produce this stuff and call it Sn100C. I have the "Kristall 400" in 0.5mm diameter which I sometimes use for manual SMD assembly. The flux inside smells horrible and you really don't want to breathe this stuff, however it seems to be well optimized for the alloy. They also sell a Kristall 511 which uses different flux, but I haven't tried that one yet.
Edit: So if you want to get Sn100C in the EU, Stannol is probably the way to go. You can buy some variants on tme.eu (Transfer Multisort Elektronik from Poland) but in general I would suggest using the selection tool on their website to figure out what exact product number you are looking for.
Edit: So if you want to get Sn100C in the EU, Stannol is probably the way to go. You can buy some variants on tme.eu (Transfer Multisort Elektronik from Poland) but in general I would suggest using the selection tool on their website to figure out what exact product number you are looking for.
Last edited:
Germanium-doped 99.3/0.7 (Sn/Cu) is the generic name for Sn100C. Kester has a bismuth-doped version called K100LD.
You can get them without the Ge/Bi doping, but supposedly the doping helps agains bridging. The doping doesn't add much cost (maybe +5%) so it seems worth getting. You can find it on Digikey as "Sn99.244Cu0.7 (Ni0.05Ge0.006)". That should be easy to remember ... NOT!
Actually, it's the only alloy that lists Ge, so even if it's hard to remember, it's easy to find in the list.
Tom
You can get them without the Ge/Bi doping, but supposedly the doping helps agains bridging. The doping doesn't add much cost (maybe +5%) so it seems worth getting. You can find it on Digikey as "Sn99.244Cu0.7 (Ni0.05Ge0.006)". That should be easy to remember ... NOT!
Actually, it's the only alloy that lists Ge, so even if it's hard to remember, it's easy to find in the list.Tom
I guess that the general idea is lifecycle management: reduce environamental impact of electronic waste by discuraging mass manufacturing of subassemblies that contains harmful or hard to recycle materials and exceeds the planned life of the complete product. Planned obsolescence is done more effectively by software means on today connected devices, there is not a compelling need to introduce weak points on the hardware for this purpose. After accepting the concept that consumer devices life has been planned, there is no need to build devices like they will last forever. Early professional personal computers and minicomputers were built to last decades, but have been trashed only after a few years of use because they were unable to run the upgraded software. A colossal waste of good resources. Today devices will not last any longer, but at least they have been built with cheaper and less harmful matherials.
I have been using Pb/Sn solder, since I was about 6-7 years old, now at 67 I wonder if the lead affected my early development & will never know. Apparently there are a lot of symptoms of lead poisoning: Lead poisoning - Symptoms and causes - Mayo Clinic
Apparently diets that that include enough; Vitamin C, Calcium, Iron, Zinc & Phosphorus help with reducing Pb absorption.
We had a major effort at work over the last 20 years to provide reliable Pb free packages & there were lots of issues with Sn whiskers. We also had a lot of issues with Cu dendrites (Au flashing can fix this but is expensive) growing during burn in life tests. It seems the EU has requirement for Pb free products; Packaging Waste Directive - Heavy Metals Concentration Level - heavy-metals-packaging-waste - ECHA
The power products that use Pb solder die attach were also a problem for customers wanting to eliminate lead. Regular Pb solder die attach is much more reliable with less voids (for high power dissipation applications) than alternatives. Some applications have moved to sintered Ag-Glass die attach, which cheaper than Au eutectic die attach.
I tried some lead free solder recently, but was not impressed. A few months ago a bought a roll of Kester 24-6337-8800 50 Activated Rosin Cored Wire Solder Roll, 245, 63/37 Alloy solder, which seems to work fine.
Apparently diets that that include enough; Vitamin C, Calcium, Iron, Zinc & Phosphorus help with reducing Pb absorption.
We had a major effort at work over the last 20 years to provide reliable Pb free packages & there were lots of issues with Sn whiskers. We also had a lot of issues with Cu dendrites (Au flashing can fix this but is expensive) growing during burn in life tests. It seems the EU has requirement for Pb free products; Packaging Waste Directive - Heavy Metals Concentration Level - heavy-metals-packaging-waste - ECHA
The power products that use Pb solder die attach were also a problem for customers wanting to eliminate lead. Regular Pb solder die attach is much more reliable with less voids (for high power dissipation applications) than alternatives. Some applications have moved to sintered Ag-Glass die attach, which cheaper than Au eutectic die attach.
I tried some lead free solder recently, but was not impressed. A few months ago a bought a roll of Kester 24-6337-8800 50 Activated Rosin Cored Wire Solder Roll, 245, 63/37 Alloy solder, which seems to work fine.
Attachments
Last edited: