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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #21 Posted: Wed Apr 09, 2014 7:33 am 
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Not just electronics in fact. Afaik, it applies to every lead-based material. Maybe i'm wrong about that, I didn't check. Still doesn't change my point though, unless you eat the stones, it should do you no harm :)

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #22 Posted: Wed Apr 09, 2014 7:48 am 
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Pericles wrote:
Not just electronics in fact. Afaik, it applies to every lead-based material. Maybe i'm wrong about that, I didn't check. Still doesn't change my point though, unless you eat the stones, it should do you no harm :)


wikipedia wrote:
The RoHS directive took effect on 1 July 2006, and is required to be enforced and become law in each member state. This directive restricts (with exceptions) the use of six hazardous materials in the manufacture of various types of electronic and electrical equipment.


Emphasis mine. I agree that unless you swallow them, the risk is very minor. The thing is, touching the stones and then touching your lips, or eating while playing, or... can actually be a moderate risk. With long exposure, a relative risk, after all, lead does not go away, it just accumulates on human bodies.

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #23 Posted: Wed Apr 09, 2014 11:27 am 
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RBerenguel wrote:
The thing is, touching the stones and then touching your lips, or eating while playing, or... can actually be a moderate risk. With long exposure, a relative risk, after all, lead does not go away, it just accumulates on human bodies.

I seriously doubt it.

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #24 Posted: Wed Apr 09, 2014 12:36 pm 
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Depends on how easily lead leaves the surface of Yunzi stones. In any case, I wouldn't risk it if possible.

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #25 Posted: Wed Apr 09, 2014 1:14 pm 
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xed_over wrote:
RBerenguel wrote:
The thing is, touching the stones and then touching your lips, or eating while playing, or... can actually be a moderate risk. With long exposure, a relative risk, after all, lead does not go away, it just accumulates on human bodies.

I seriously doubt it.

Doubt is A Good Thing™, doubt and curiosity are what drives science :-)

Wikipedia —> Lead —> 7 Health Effects

And the next chapter, 7.1 Biochemistry of poisoning, begins with
Quote:
Exposure to lead and lead chemicals can occur through inhalation, ingestion and dermal contact.

“dermal contact” … skin contact.

Yes, this is Wikipedia, but it is a good start, IMHO.

Greetings, Tom

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #26 Posted: Wed Apr 09, 2014 2:05 pm 
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I wouldn't be worried by lead in glass Go stones.

Lead in paint is a serious problem. Children can eat flakes of it, and can be poisoned as a result. But this happens because flakes of paint are to some extent soluble. But glass is not soluble; not in water, not in stomach acid and other acids, not in alkalies; that is why it is used for glassware. So if a child swallows a glass Go stone, it will just pass through, unaffected.


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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #27 Posted: Wed Apr 09, 2014 2:39 pm 
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maproom wrote:
I wouldn't be worried by lead in glass Go stones.
Glass Go stones certainly don’t contain lead.

Quote:
Lead in paint [..] to some extent soluble. But glass is not soluble [..] So if a child swallows a glass Go stone [..]
Yunzi is NOT glass, it is a ceramic, it is mostly stone powder that has been sintered, i.e. pressed and baked together with great heat, and thus it is porous.

They used to (and some perhaps still do) add lead powder for weight, and this lead can be abrased from the porous surface with skin contact. Also, it has happened that yunzi stones break, and, according to those who wrote about it, some of their broken stones contained a white-ish, powdery substance. I assume this can happen when for example the sintering was incomplete and the stones have not been “baked” long enough or with too little heat.


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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #28 Posted: Wed Apr 09, 2014 2:54 pm 
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Bonobo wrote:
maproom wrote:
I wouldn't be worried by lead in glass Go stones.
Glass Go stones certainly don’t contain lead.

Quote:
Lead in paint [..] to some extent soluble. But glass is not soluble [..] So if a child swallows a glass Go stone [..]
Yunzi is NOT glass, it is a ceramic, it is mostly stone powder that has been sintered, i.e. pressed and baked together with great heat, and thus it is porous.

They used to (and some perhaps still do) add lead powder for weight, and this lead can be abrased from the porous surface with skin contact. Also, it has happened that yunzi stones break, and, according to those who wrote about it, some of their broken stones contained a white-ish, powdery substance. I assume this can happen when for example the sintering was incomplete and the stones have not been “baked” long enough or with too little heat.


Greetings, Tom


its not added for weight. Its added to lower the melting point for the glass (or ceramic, which is a form of glass), to make the molten glass easier to work with.

viewtopic.php?p=90688#p90688

and the powdery substance inside broken stones is just the "stone" mixture itself from improper cooling.

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #29 Posted: Wed Apr 09, 2014 5:06 pm 
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xed_over wrote:
[..]

its not added for weight. Its added to lower the melting point for the glass (or ceramic, which is a form of glass), to make the molten glass easier to work with.

viewtopic.php?p=90688#p90688

and the powdery substance inside broken stones is just the "stone" mixture itself from improper cooling.

Thank you, I’m aware of that thread, yet I’ve read different information about this elsewhere.

OK, so it’s not added for weight, but it has been added. BUT glass ≠ ceramic, glass is rather a subcategory of ceramics, as I understand it.

http://chemed.chem.purdue.edu/genchem/t ... html#glass
http://www.differencebetween.net/object ... -ceramics/
http://en.wikipedia.org/wiki/Ceramic
http://en.wikipedia.org/wiki/Glass

Thanks, I’ve learnt something :-)

Before I only knew that glass is amorphous and made from molten silica, plainly said: molten sand (plus some additions for lowering the melting point), and that ceramics are baken (burnt? kilned? It began with clay), and that they are not molten as much as glass, or better perhaps to say that they are not as liquid/fluid/ as molten glass is. And that Yunzi is a sintered ceramic made from stone meal (with a süper sikrit recipe), under pressure and heat, thus the porosity. I have a set of Yunzi with a green-ish luster which are said to be made with a certain amount of powdered green Jade.

Sadly, I can’t remember all my sources since it’s been a while since I learnt about this, but there’s some info about Yunzi (though not about the lead, unless I overlooked it) on Sensei’s Library here: http://senseis.xmp.net/?Yunzi and http://senseis.xmp.net/?Yunzi%2Fdiscussion

Respectfully, Tom

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #30 Posted: Wed Apr 09, 2014 10:36 pm 
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Bonobo wrote:
Before I only knew that glass is amorphous and made from molten silica, plainly said: molten sand (plus some additions for lowering the melting point), and that ceramics are baken (burnt? kilned? It began with clay), and that they are not molten as much as glass, or better perhaps to say that they are not as liquid/fluid/ as molten glass is. And that Yunzi is a sintered ceramic made from stone meal (with a süper sikrit recipe), under pressure and heat, thus the porosity. I have a set of Yunzi with a green-ish luster which are said to be made with a certain amount of powdered green Jade.

looks pretty molten/liquid/fluid to me...
[youtube]https://www.youtube.com/watch?v=rPdk6PbFbZk[/youtube]

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #31 Posted: Thu Apr 10, 2014 8:00 am 
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xed_over wrote:
[..]

looks pretty molten/liquid/fluid to me...
[youtube]https://www.youtube.com/watch?v=rPdk6PbFbZk[/youtube]

Oh. Thank you, learnt something again, I stand corrected.

I did read somewhere that Yunzi was a sintered material (even the Wikipedia page I quoted earlier says so), but, sadly, I don't remember my original source.

Anyway, now I know it isn’t so, thank you. (I really hate being wrong, but I love learning new stuff ;-) )

(just the video number, not the whole URL, then it works)

(fast forward to 02:07 and 03:40)

What still remains is that Yunzi is somewhat porous, that it is less smooth than glass (as anyone who has ever touched and seen both can attest).

<shrug>

And so, since lead is hazardous, I’d still recommend to stay clear of Yunzi that contain lead.


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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #32 Posted: Thu Apr 10, 2014 10:03 am 
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I noticed this post after I bought a set of these stones--even though I cannot find anyone to play with over the board. I never thought that solid lead objects, such as lead toy soldiers, posed a major health hazard as long as they are not ingested. So I checked OSHA (https://www.osha.gov/pls/oshaweb/owadis ... p_id=10031):

"Lead can be absorbed into your body by inhalation (breathing) and ingestion (eating). Lead (except for certain organic lead compounds not covered by the standard, such as tetraethyl lead) is not absorbed through your skin. When lead is scattered in the air as a dust, fume or mist it can be inhaled and absorbed through you lungs and upper respiratory tract. Inhalation of airborne lead is generally the most important source of occupational lead absorption. You can also absorb lead through your digestive system if lead gets into your mouth and is swallowed. If you handle food, cigarettes, chewing tobacco, or make-up which have lead on them or handle them with hands contaminated with lead, this will contribute to ingestion."

So, as long as I don't lick the stones or my fingers--and don't start snorting broken stones--I think I will be pretty safe. At least compared to all of the chemicals in my air, water, and food. :shock:

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #33 Posted: Thu Apr 10, 2014 10:31 am 
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Bonobo wrote:
(just the video number, not the whole URL, then it works)

Wow, that was not obvious. Thanks.

Bonobo wrote:
What still remains is that Yunzi is somewhat porous,

I don't have any to test, but I have my doubts here too. :)

According to the Wikipedia article posted in the other thread (and a few other links in a quick Google search for lead leaching), one could probably soak their stones in whisky for a while to leach most of the lead off the surface of the stones (assuming they are not porous). Just don't drink the whisky afterwards.

And while the lead content is already far below Health and Safety regulations, then it will be even less (for the truly paranoid).

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #34 Posted: Mon Apr 14, 2014 1:57 am 
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xed_over wrote:
Bonobo wrote:
(just the video number, not the whole URL, then it works)

Wow, that was not obvious. Thanks.

Bonobo wrote:
What still remains is that Yunzi is somewhat porous,

I don't have any to test, but I have my doubts here too. :)

According to the Wikipedia article posted in the other thread (and a few other links in a quick Google search for lead leaching), one could probably soak their stones in whisky for a while to leach most of the lead off the surface of the stones (assuming they are not porous). Just don't drink the whisky afterwards.

And while the lead content is already far below Health and Safety regulations, then it will be even less (for the truly paranoid).


To spare you (and your whisky) I believe that vinegar (or if you have it available citrate / citric acid) is the preferred method for leeching lead out of household items. I don't know that it will do it in large enough concentrations to cleanse your stones though.

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #35 Posted: Wed Apr 16, 2014 11:15 am 
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xed_over wrote:
And while the lead content is already far below Health and Safety regulations....

I think this is a key point that people seem to be glossing right over.


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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #36 Posted: Fri Apr 18, 2014 4:57 am 
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To be honest, I don't understand the discussions.

Lead is a highly poisonous material and can lead to health issues. Even in small doses.

If you don't care about possible health hazards, then play with Yunzee stones.

If you are scared of possible health hazards, don't play with Yunzee stones.

It's the same with any other dangerous material. (Smoking, alcohol, etc.)

You decide what you do to your body.


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Post #37 Posted: Fri Apr 18, 2014 1:22 pm 
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Hong Ny wrote:
To be honest, I don't understand the discussions.

Same here.

Dangerous materials are all around you, every day, all the time. In the air you breathe, in the water you drink, in the food you eat... wall-paint, plastics, carpet-cleaners, cell-phones, and so on... you can agonize over all of this if you are really paranoid, or you can decide that certain levels are safe and go on with your life. And try to minimize the big influences, its what you can do.

Personally, I think some of the stuff listed on the labels of the stuff you actually consume is much more dangerous to your health that the spurious amounts of lead there might or might not be in a Go stone which might or might not actually get into your system. Not to mention the stuff which is *not* listed on labels yet because nobody managed to force the corporations to disclose them. Yet. Or because it is not apparent that they are dangerous until the next generation starts dying off from some weird stuff nobody knows about yet.

I'd rather swallow a Go stone than eat at TacoBell or MacDonald, for example.
And having said that, I have done all 3, and I am still here and still healthy. ;)

If the worst you think you have to worry about is the trace amounts of lead in Go stones, you must be living in paradise.

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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #38 Posted: Fri Apr 18, 2014 1:36 pm 
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there _is_ a difference … lead accumulates, and … it makes dumb. Easy as that.

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Post #39 Posted: Fri Apr 18, 2014 3:23 pm 
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A woman walks into a doctors office and says, "I want to sue! My son is retarded after eating his go stones which contained lead."

The lawyer pauses a moment and responds, "Don't you mean your son is more retarded after eating his go stones which contained lead?"


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 Post subject: Re: Warning, Yunzi Stones Are Dangerous To Health
Post #40 Posted: Wed Jun 11, 2014 2:02 am 
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Hong Ny wrote:
with Yunzee stones


Yunzi. The "zi" bit sounds like the vowel in Sid or Kid. Not like bee or tree.

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