antique porcelain toxicity? safe to drink from old ceramic?


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antique porcelain toxicity? safe to drink from old ceramic?

Postby collector » Nov 10th, '11, 20:09

Hello

I am interested in antique 19th hand painted porcelain. I know that lead is present in old paintings, but, used only sometimes do you think is a real risk? Any of you does collect and uses old teaware?

Thanks
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby JBaymore » Nov 10th, '11, 21:53

Porcelain itself is fired to a high temperature...... around 1300 C. Lead as a flux on silica is not really useful at that temperature; it volatilizes out of the glaze melt and goes out with the gases escaping from the kiln.

The place you CAN find lead however is in the colorful overglaze enamels that are sometimes added in separate lower temperature firings. Those traditional overglaze enamels are a highly lead fluxed composition and are fired so low as to be very unstable for the leaching of lead from the fired surface.

On the flip side, the usual amount of the surface actually COVERED by overglaze enamels is usually small. So the amount of glaze surface available to leach lead is small.

So if you are talking about a plain porcelain piece.... it is perfectly safe. With overglaze on it, if it is a TINY amount painted on the inside on the liquid contact surface... your are probably OK (but no guarantees). If it is a large amount of overglaze inside,.... take a pass on that one.

best,

..................john
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby collector » Nov 11th, '11, 06:32

Thanks your aswer.

Then, regarding that aspect of highly painted pieces, I wonder what would happen to general population in Victorian Times when these pieces were common.

Regrds :wink:
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby TIM » Nov 11th, '11, 07:12

collector wrote:Thanks your aswer.

Then, regarding that aspect of highly painted pieces, I wonder what would happen to general population in Victorian Times when these pieces were common.

Regrds :wink:


Are you refering to Victorian Chinese Exports or Victorian English wares?
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby JBaymore » Nov 11th, '11, 10:00

collector wrote:Thanks your aswer.
Then, regarding that aspect of highly painted pieces, I wonder what would happen to general population in Victorian Times when these pieces were common.


Undiagnosed various levels of lead poisioning.

best,

................john
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby bearsbearsbears » Nov 11th, '11, 14:15

Lead is not the only heavy metal in the overglaze that can leach out and cause problems...if brewed tea is in contact with overglaze painting on an antique piece, it's best to not use those pieces too frequently.
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby collector » Nov 13th, '11, 11:57

TIM wrote:
collector wrote:Thanks your aswer.

Then, regarding that aspect of highly painted pieces, I wonder what would happen to general population in Victorian Times when these pieces were common.

Regrds :wink:


Are you refering to Victorian Chinese Exports or Victorian English wares?

I am referring, mainly to Englisg 19th porcelain but also from ther countries.
Then, even drinking sometimes at year is a real risk, or only is risy ifone uses it frequently?
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby JBaymore » Nov 13th, '11, 15:12

There is no way to answer this precisely at all. We don't have enough data. It all depends on the specific piece, what exactly is meant by "frequently" and for how long a period of time you do that thing "frequently".

In general, toxicological issues revolve around frequency, intensity, and duration of exposure.

As a BROAD generality (with exceptions), more often is worse than less often. Higher intensity is worse than lower intensity. A longer duration of exposure is worse than a shorter duration.

The first piece of data needed is exactly WHAT level of leaching the piece exhibits. If you have a particular piece you are concerned with, you CAN have it leach tested for lead release (or anything else). It is MINIMALLY destructive testing though. A lechate solution is placed in it for a precise duration and then the liquid is tested for the substance in question. That number will give the basis for deciding on ANY other thoughts.

Lacking that leaching number, all that can be said is VERY broad generalities.

best,

.................john
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby collector » Nov 14th, '11, 08:02

Thanks for your answer ;)

I am totally concerned with lead health issues, but, as I asked in a previous message, I wonder how in past times when almost everyone drank from these pieces daily,since chilhood, it didn´t happen a general, massive and fatal intoxication.

Regards
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby JBaymore » Nov 14th, '11, 08:44

collector wrote:.......I wonder how in past times when almost everyone drank from these pieces daily,since chilhood, it didn´t happen a general, massive and fatal intoxication.


Because in past times, there was not the sophistication of diagnosis for such things as low level lead poisioning. Lead is not instantly "fatal". Fatal doses are rare. Generally speaking it is a cumulative, slow situation of subtle deterioration. The effects are slow to show up and can also be mis-attributed to other problems. By the time a person is approaching a fatal dose, they have long had overt and dramatic symptoms.

In some cases in some eras, lead poisioniong was simply "ignored" as a "cost of living" :shock: .

It is only relatively recently that we have become aware of the damage that even low levels of lead in the body can do. Particualrly to kids.

This below is a well known reference on this subject that those of us who teach ceramic toxicology are well aware of.... thought you'd find it of interest:

http://www.rachel.org/files/document/Le ... ective.pdf

best,

.............john
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby night.owl » Nov 14th, '11, 10:31

collector wrote:Thanks for your answer ;)

I am totally concerned with lead health issues, but, as I asked in a previous message, I wonder how in past times when almost everyone drank from these pieces daily,since chilhood, it didn´t happen a general, massive and fatal intoxication.

Regards


There's an interesting section at the Crime Museum in Washington, DC that addresses just this problem. Back in the early days (I forget just which time frame they are suggesting, but it was early US), only the "upper class" could afford imported pottery pieces for everyday food and beverage use. As it turns out, many of them died of lead poisoning as a result. They referred to it as some sore of rich person's curse of the time.
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby Ludwig-1954 » Nov 14th, '11, 11:53

I would not really worry too much about lead poisoning from drinking
teac in possibly contaminated cups. Tea is not or only very mildly acidic. It will thus - if at all - only dissolve very small amounts fom your TeaToys.

Perhaps you should focus your attention on other substances you are ingesting, softeners, nano particles, polluted air, chlorine in tap water,
solvents, tar/asphalts, residual antibiotics and pesticides in meat, the list is endless.

Enjoy your tea, enjoy your Teatoys, remember that life is fatal and
stop worrying

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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby Chip » Nov 14th, '11, 12:31

Ludwig-1954 wrote:... remember that life is fatal and stop worrying

Yes, but let's not hasten the arrival to our final destinatination too quickly.

Some precautions and the understanding of the dangers involved will help to make somewhat educated decisions ... or best guesses in some cases. Risk management at best sometimes, albeit. No sense being an ignorant (and prematurely dead) fool.

But we must all draw our own lines ... some things I just won't do. I won't drink from an internally painted Kutani cup, for instance. It would just distract and worry me too much.
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby night.owl » Nov 14th, '11, 12:33

Chip wrote:
Ludwig-1954 wrote:...But we must all draw our own lines ... some things I just won't do. I won't drink from an internally painted Kutani cup, for instance. It would just distract and worry me too much.


Totally agreed. In fact, I've passed up some very interesting pieces for just that reason. It would annoy me too much not to be able to drink out of them without worrying.
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Re: antique porcelain toxicity? safe to drink from old ceramic?

Postby collector » Nov 14th, '11, 18:54

Thanks for your answers. Thanks, also, JBaymore, for your very interesting PDF document.

Then, only antique tea/cofee ware not painted inside is safe although it is externally painted?
also, I suppose that although the piece is not internally painted, if the rim is gold colour, there is also risk.
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