Eating from plates made with barium carbonate?

[freddyfrink]

Hello, I am doing some research on these ceramic plates that I bought.

Customer service informed me that the plates were made of: "The stoneware is made of clay, feldspar, quartz and the coating is composed of feldspar, calcspar, kaoline, barium carbonate and pigment."

I am concerned, would this leach the barium carbonate in to food while eating? Is this safe and nontoxic? Would the barium oxide become part of the glaze and not a threat, or such a small amount it would not matter?

Thank you so much for your wisdom! I am having a very hard time finding out this type of information.

[Min]

A lot depends on the glaze chemistry plus the firing. Only way you are going to know for sure is to have a sample tested. BSC labs does glaze testing, you would need to send in something like a cup that they can use to test the glaze. If you pay for return shipping they probably could return it to you. It's approx $30- per oxide being tested. (sometimes more, depends on what oxide they are testing for) I don't know if they can test a plate surface, would have to ask them. They ask for a cup / cylinder shaped pot.

https://bsclab.com/pottery-testing

A simple home test to rule the glaze out as being durable would be to half fill a cup with household white vinegar then leave it sit for 2 days. Rinse and dry the cup and see if there is a change in either gloss or colour. If there is the glaze is leaching something, could be barium or could be some of the colourants. This test checks for glazes susceptible to acid attack. To check a glazes durability to alkalinity leave a piece in the dishwasher for a couple months then compare the surface to a plate that hasn't been through the dishwasher.

[freddyfrink]

Thank you so much min!

1 minute ago, Min said:

A lot depends on the glaze chemistry plus the firing. Only way you are going to know for sure is to have a sample tested. BSC labs does glaze testing, you would need to send in something like a cup that they can use to test the glaze. If you pay for return shipping they probably could return it to you. It's approx $30- per oxide being tested. (sometimes more, depends on what oxide they are testing for) I don't know if they can test a plate surface, would have to ask them. They ask for a cup / cylinder shaped pot.

https://bsclab.com/pottery-testing

A simple home test to rule the glaze out as being durable would be to half fill a cup with household white vinegar then leave it sit for 2 days. Rinse and dry the cup and see if there is a change in either gloss or colour. If there is the glaze is leaching something, could be barium or could be some of the colourants. This test checks for glazes susceptible to acid attack. To check a glazes durability to alkalinity leave a piece in the dishwasher for a couple months then compare the surface to a plate that hasn't been through the dishwasher.

Well my new apartment won't have a dishwasher, so I will be handwashing all my dishes. But I can definitely try the white vinegar test for a couple days. I will see if that works. Do any dishes ever pass that test? xD

 

[PeterH]

On 8/16/2022 at 12:45 PM, freddyfrink said:

Hello, I am doing some research on these ceramic plates that I bought.

Customer service informed me that the plates were made of: "The stoneware is made of clay, feldspar, quartz and the coating is composed of feldspar, calcspar, kaoline, barium carbonate and pigment."

Has anybody any idea why there would be barium carbonate in a black glaze? ... on second thought maybe it's to give a velum matt finish. 

If the barium isn't significantly effecting the colour, and the glaze is already matt,  would this minimise the chances of a vinegar test showing anything (even if barium was being leached)?

[Babs]

Think many years ago in a heavy  reduction firing , I had a barium containing satin matte glaze go black matte, colourant was copper. Oxidation , the ubiquitous  bright turquoise.

[Bill Kielb]

Interesting reading some of the one star reviews. Dismissing the arrived broken, several that  standout: glaze cracking after eight months, scratch easily with a fork, not dishwasher proof - glaze comes off. Glaze missing, color difference, glaze comes off on its own, foot ring sharp and scratch my table. There are many good reviews but it probably would be wise to be sure to test these as practical.

Edited August 17, 2022 by Bill Kielb

[Babs]

@PeterHThink it aids with that metallic look folk seem to like eating from a.t.m.

If prepared to sell barium based  dinnerware, could also contain chrome, eh?

[freddyfrink]

On 8/17/2022 at 3:57 AM, Bill Kielb said:

Interesting reading some of the one star reviews. Dismissing the arrived broken, several that  standout: glaze cracking after eight months, scratch easily with a fork, not dishwasher proof - glaze comes off. Glaze missing, color difference, glaze comes off on its own, foot ring sharp and scratch my table. There are many good reviews but it probably would be wise to be sure to test these as practical.

I will have to try to fork and knife test this as well. Thank you for pointing this out. I really hope this glaze is safe.

[freddyfrink]

On 8/16/2022 at 1:13 PM, Min said:

A lot depends on the glaze chemistry plus the firing. Only way you are going to know for sure is to have a sample tested. BSC labs does glaze testing, you would need to send in something like a cup that they can use to test the glaze. If you pay for return shipping they probably could return it to you. It's approx $30- per oxide being tested. (sometimes more, depends on what oxide they are testing for) I don't know if they can test a plate surface, would have to ask them. They ask for a cup / cylinder shaped pot.

https://bsclab.com/pottery-testing

A simple home test to rule the glaze out as being durable would be to half fill a cup with household white vinegar then leave it sit for 2 days. Rinse and dry the cup and see if there is a change in either gloss or colour. If there is the glaze is leaching something, could be barium or could be some of the colourants. This test checks for glazes susceptible to acid attack. To check a glazes durability to alkalinity leave a piece in the dishwasher for a couple months then compare the surface to a plate that hasn't been through the dishwasher.

For the home test, out of curiosity, do any ceramic plates ever pass this?

[Bill Kielb]

2 hours ago, freddyfrink said:

For the home test, out of curiosity, do any ceramic plates ever pass this?

I’ll give you my take. The vinegar test is very helpful and many glazes ought to pass it. Does it indicate durability, not necessarily so. It’s a nice test that can be done at home and any commercial ware ought to easily pass it IMO. Will it predict some of the complaint issues mentioned earlier which could go to glaze durability, glaze fit? Most likely not. Will it always predict leaching? Really not necessarily so, that is more of a lab thing. It’s definitely a good test to pass though. When a glaze does not pass it, for sure it is usually judged not a good glaze for food consumption.