Stoneware Teapot.... Lead???

[Tadpole]

Has anyone purchased any of the stoneware gongfu teapots from Tao of Tea? See link below. I just bought this black one. It resembles a traditional yixing teapot. I know it is NOT a yixing, I bought it hoping I could have a small stoneware teapot to use for any tea without worrying about absorption of flavors. I've emailed Tao of Tea already requesting more info on the material and glaze used. I guess I should have done this before ordering the thing! Oh well. Awaiting their answer. Worst case scenario, I'll only be set back $10 + shipping, and I could use it as a small planting pot that has built-in drainage

http://taooftea.com/detail.php3?pid=215 ... 9zY2M9NDk=

[JRS22]

From the photo it appears that the outside has a matte finish. Is the inside matte or glossy? My pottery teacher may be conservative, but she advises against some matte finish glazes for teaware. I do remember last year someone testing glazes by keeping them partially submerged in vinegar (?) for a while and then inspecting for changes in the appearance of the glazes.

[JBaymore]

If the company is in the USA, it is SUPPOSED to be complying with the US FDA regs on the leaching release of lead in tablewares. Imported ware is supposed to be screened relative to this. However #1......the pot is sourced out of India...... where lead compounds are a very traditional glaze flux. However #2........if the piece is truly fired at stoneware temperatures, very little if any lead would likely remain in the glaze melt due to the volatility of that flux at the elevated stoneware temperatures.

In the end... you are depending a lot on the supplier for this.

Also..... I'd be wondering just a bit about how they are getting that gunmetal black finish. One of the typical ways to achieve that effect is to supersaturate the cooling glassy melt with more metallic colorants than it can hold in solution. (Like making rock sugar candy.) The coloring metals involved and some of the silica and alumina and other fluxes in the glaze precipitate out onto the glaze's surface to form micro-crystalline structures... making a nice gunmetal looking smei-matte to matte surface. Problem is, these materials are not then as tightly bound into the glassy phase of the melt,... and can therefore far more easily leach out. One of the common coloring oxides for blacks....... manganese dioxide.... has some serious potential health consequences if ingested. Causes something pretty much indistinguishable from Parkinson's Disease.

There are no regulations on stuff like manganese in glazes in the USA. Only lead and cadmium are regulated.

best,

.....................john

[shyrabbit]

Thanks John, for your typically thorough response,
One of my early inspirational potters was, David Shaner. His manganese blacks were stunning, I still use his "Baby Doll Black" on sculptural works.

He died several years ago, due to nervous system problems due to heavy metal poisoning (similar to Parkinson's Disease).

The heavy metal build up in his system was accelerated by inhaling dry manganese dioxide dust, possible migration through the skin when mixing glazes and breathing fumes when firing the wares. I think before Shaner's demise little was known of the hazards of these metals to potters. Now potters are looking to be tested to monitor their heavy metal levels, regularly.

As a potter these metals can be used safely when certain precautions are taken. IMO, Certain levels of manganese should never be used in a functional glaze regardless of the glass formed containment. Again, IMO no level of manganese is safe in a low silica or matte glaze.
Michael

[TIM]

Its very funny that the small photo does not match the large photo. They are both very different tea pot, in the made to clay quality.

[MarshalN]

Not just the clay but the shape -- the lids are different.

[Tadpole]

Kind of late, but thanks everyone for responding. I appreciate the in depth considerations. I have not heard back from Tao of Tea. I will just keep this thing on a shelf to look pretty. Too scared to use it to brew tea! Note to self: do not buy stuff on a whim, just don't.