[sdiy] Transition to Lead-Free Hand Soldering

Sat Aug 21 14:57:52 CEST 2021

Unless you're a registered business selling finished electronics
products enclosed in a housing, no one will care if you sell stuff
that's not RoHS. As I understand, RoHS does not apply to replacement
parts, for example.

Nothing regarding health in the EPA leaflet is substantiated by any
sort of research. For environment, SnPb even according to that leaflet
is *less* bad than lead-free.

Pallor and blue gums are good markers of lead poisoning. However,
you're talking about people working in soldering shops. Let's think
about what this is. Start with dozens of multiple fuming,
high-temperature soldering irons in a, most likely, enclosed room.
Most likely bad ventilation because fume extraction wasn't popular at
all back then, never mind activated coal filtering. And then most
likely in the same room or close by you had lead-based wave soldering,
which means a huge pool of molten lead exuding fumes at all times.
Those were extremely bad circumstances and one needs to be aware of
them. But this does not reflect low-volume manufacture...

Let's look at one example of a person afflicted with such illness:

https://casereports.bmj.com/content/12/4/e227954

"Laboratory investigations showed high blood lead levels (91 ug/dL)."

For 50 dL of blood (a normal amount in the body), you'd need 5000
micrograms of lead. To reach this concentration of lead in the blood
serum you'd need to melt and inject several mm of soldering wire into
your blood stream.

The boiling point of lead is 1749 C. This is 1500 C above what you
should be soldering at. Unless you're soldering with an acetylene
torch, the fumes from your soldering will not contain any lead at all.
The only reason you can get poisoning at lead shops is that they have
huge surfaces of molten lead with flux that reduces surface tension,
which allows non-gaseous particles to diffuse into air, similarly like
how a pot of water kept warm will eventually evaporate in a completely
dry room, given a lot of time. Spending 10-16 hours a day, over 30-40
years, in such a place is a different than, as you describe, creating
"a small run of modules".

Unless you fill your bathtub with perpetually molten lead and inhale
for 10 hours a day for years, you're unlikely to reach any sort of
level reminiscent of that BMJ study.

However, it's important to note that blue gums and a pale complexion
can be due to a host of various health issues. It's just called
getting old. When you get old I'm sure you'll notice this or that
symptom that someone could blame on your use of whatever chemical in
your youth. And let's be honest, no one who spends 10 hours a day with
a soldering iron is going to be living a healthy lifestyle - most
people who are of such technical nature... just don't care, and they
pay for that in later years. You just saw someone who's old, doesn't
exercise, and doesn't have a good diet. I'm not surprised they were
pale and had gum disease.

The EPA leaflet is not a study, and it is full of crap. I have to say
that recent events completely discredit anything related to the
environment to come out of the US Government, which created the
legislation, funded, gave tax breaks to, and supported the development
of Deepwater Horizon, the recent Gulf of Mexico ring of fire, as well
as many other major disasters, recent or not (like the atom bombing of
Japan). This specific study came out of George W's EPA and, to put it
bluntly, any regulations related to industry are fully dictated and
decided by the rich leaders of the respective industry, through
billions spent on lobbying (3.5 billions in 2020). That is an
unimaginable amount. Be wary of what you believe there.

Lead impact on human body is well known. However, most studies focus
on leaded water pipes, which create a high concentration in the body,
because you ingest the lead. Even if you solder touching lead with
bare hands, even if you don't wash your hands, it'll be difficult to
reach anything near those levels. Medical publications mention 20% of
lead ingested is absorbed. The half-life of lead in soft tissues and
blood is at most 1.5 months. 35 years in bones, so don't eat lead
during growth spurts (until you're 35). Whatever is left on your
fingers after holding soldering wire will be in single microgram
digits. Even if you lick your fingers right after, you're going to get
a very small amount of lead.

What I can tell you is that I have been soldering with lead my whole
life in a hobbyist amount and I haven't got blue gums - but my blood
work does not include lead levels, so I can't tell you whether I've
been personally affected.

On Sat, Aug 21, 2021 at 1:13 PM dh at atoav.com <dh at atoav.com> wrote:
>
> On 21/08/2021 12:54, Adam Inglis (synthDIY) wrote:
> > The reference you quote is dated August 2005.
> > It talks about the contribution of tin-lead (SnPb) solder to ozone depletion and acid rain (among other things). Even global warming gets a mention.
>
> Yes it is a life cycle assessment summary, as it says on the first page.
> I chose this source, because cheatercheater was talking about both
> health AND environment and it summarized both things in a nize overview
> table (including confidence in each finding).
>
> > I’m not an expert in this field but it sounds more like a PhD pitch than hard evidence? And it does have that modern ring of alarmism…
>
> It is a study done for the United States Environmental Protection
> Agency. What else would you need for "hard" evidence? A long term self
> study involving lead solder fumes?
>
> If you ever met one of the old solder guys from any bigger electronics
> shop you can _see_ that the lead had impact on them (color of the skin,
> pallor, lividity, bluish gum/teeth etc). The impact lead can have on the
> human body is known since the 50s, so I if this is alarming news to you
> I am happy you learned something today : )
>
> >> On 21 Aug 2021, at 8:24 pm, dh at atoav.com wrote:
> >>
> >>
> >>
> >> On 21/08/2021 11:01, cheater cheater wrote:
> >>> Leaded paste is easily available. Unless you're a manufacturer, RoHS
> >>> doesn't matter. Less lead will contrary to popular belief not save the
> >>> environment or anyone's health.
> >>
> >> So by changing to leaded solder paste I gain nothing but loose the
> >> potential to have a process that is RoHs conform (e.g. should I ever
> >> sell a small run of my modules)? Why would I do that?
> >>
> >> Also I am not sure what sources you base your conclusion on, but it is
> >> certainly not as simple as "it doesn't matter". It is true that
> >> lead-free is not automatically better in terms of environmental and
> >> health concerns (depending on the question you are asking), however it
> >> is certainly worse in most categories that matter to me (see [1]).
> >>
> >> As you can see in that source SnPb has a occupational health-non-cancer
> >> impact that is by _two magnitudes_ higher than all other paste variants.
> >> So if you claim this has no impact on "anyone's health" you are
> >> misleading at best unless we are talking about people who solder once a
> >> year.
> >>
> >>
> >>
> >>
> >>
> >> ---
> >> 1:
> >> https://www.epa.gov/sites/default/files/2013-12/documents/lead_free_solder_lca_summary.pdf
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