Author Topic: Is there a "one-stop" means of testing pottery to see if it safe to drink from?  (Read 2951 times)

Bradley

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I have my eye on a large pottery pitcher that could be 200 years old or it could be 20. I am wondering how safe it is to drink from and would like to know if there is a test for this. It is probably not terribly old, but in this case I am more interested in safety than I am in age. (I like the primitive look of it.) I have posted it on imgur and not gotten an answer to the question of how to test for safety. There are lead tests, like the ones you would perform on metals, but any number of different items can go into pottery glaze and have not found a "catch all" test for pottery.

I have also found that people who comment on imgur don't seem to be very serious, as you will see if you read some of the comments I got. Here is the imgur link in case you are intersted. http://bradley7777.imgur.com/all/

mart

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Can you just post the pics here please !! It would take an hour for those to load !! That is the most difficult site on the net !!

Bradley

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Sure. Here they are. Whether or not this is even an antique is highly debatable, right? That's why I hesitated posting photos. But the knowledge base here is soooooo broad, I was hoping someone might know pottery glazes or how to test them. Maybe what I really need to do is just store some water in one and test the water, because even the local hardware store has chemical testing kits for water.
« Last Edit: August 03, 2015, 09:56:05 pm by Bradley »

Bradley

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Another one. Signature on the bottom is kinda hard to decipher.

mart

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I can`t make heads or tails out of that signature !!  It looks like most of the glaze has worn off ??  That would be the safest way to check the lead content !!  They did use some lead glazes in American pottery !!  Pour some hot water in it and let sit about a week,, then test the water and see if any has leached in to it !!  Looks like either American or English stoneware,, don`t see anything that would make me think otherwise !!

cogar

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I think that a “signature” on the bottom is quite unusual for pre-1900 American pottery.

Here is some info on said. to wit:

Quote
On Pottery in Colonial America

STONEWARE: Clay which can be fired within 2% of total vitrification  or less are considered to be stoneware. Stoneware clays are usually made up of blended clay bodies to produce a malleable, strong clay which can be worked on the pottersŐ wheel and fired to a vitreous state. Color and texture of stoneware clays can vary quite a lot. Color can range from white to dark brown and texture can be smooth to coarse. Salt glazing is a process whereby sodium, most often in the form of coarse salt, is introduced into the kiln during the firing. A chemical reaction between the clay body and the salt forms the pebbly, clear glaze. Although technically salt-glazing can be performed on certain earthenwares and porcelains, this process is most commonly used on stoneware. From an historic viewpoint, it can be assumed that a salt-glazed pot is made of stoneware.   Excerpted from:  http://www.juliasmith.com/historicpottery/articles.htm

KC

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Yep, do the water test for lead!  OR, if you have a hardware or home improvement center near you they may carry the 3M lead check kit that is under $10 and great to have around for quick testing.
Here is the site for it and it lists stores that carry it.  Great to have if you get lots of older pottery.
http://leadcheck.com/

I'm from the South - but please don't mistake my Southern Manners/Accent/Charm as a weakness!

Bradley

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I agree with Cogar. I don't think it is that old either, which is why I hesitated posting it here. But I figured that if there was a safety test for pottery, someone here would know about it. I think the water testing idea is probably my best bet.

And I do have the 3M lead check kit. I have used it on many of my metals.  The only thing that tested positive for lead (in a HUGE way!) was this small pewter pitcher. I was told it was made in the early 1800s (before lead content was regulated in the U.S.)  and I can't be certain, but 3M check certainly indicated heavy lead content. The swab turns pink when it touches lead and for this vessel, it went from pink to dark pink to black! And this was on a portion of the vessel that I  thoroughly washed and rinsed, so that blackness was not from patina.

There are makers marks on the bottom, but they are so faded as to be nearly illegible.
« Last Edit: August 05, 2015, 11:05:20 am by Bradley »

KC

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How tall is the pewter piece?  Looks like a creamer or syrup pitcher. 
I'm from the South - but please don't mistake my Southern Manners/Accent/Charm as a weakness!

Bradley

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KC, it's just a shade over 5 and 3/4ths inches tall. Would not mind using it, if not for the HIGH lead content. Nice piece though, eh?

KC

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I like it!  Agree - sad that it has such a high lead content!  :(
I'm from the South - but please don't mistake my Southern Manners/Accent/Charm as a weakness!