"I am now at a point where I want to build my own kiln and develop my own pallet of glazes as well as a clay body ... I want to understand better why glazes do what they do ... how to fix them. I also want to make sure they are safe. When a friend from Japan comes in the summer I try and figure out what he does and why but he, being a master potter, seems to just go by the look and consistency of it. Boggles my mind!!!"
"I have a huge concern about liner glazes. I have run across some potters who have taught classes where they gave no direction about what is suitable for liners. When doing a simple lemon test their glaze failed miserably."
"I have been doing a LOT of reading and learned of your software through the book Mastering Cone 6 Glazes by John Hesselberth and Ron Roy. It became obvious in my reading about glazes that to glaze a piece and know that it was safe for others use and handling was paramount to me, ... people will always use an object in ways you never imagine:) I also want to know why for everything."
"We are using your 1916 glaze recipe on low fire ware and my students are asking a lot of questions about the safety of the pottery they are making, does it leach. I do not know how to answer them. Please help."
"I've just received an email from a customer about one of the mugs she bought from me. She said there was a metallic taste and stopped using the mug. Okay, so is this possible, that there would be some kind of leaching from the glaze that would cause a metallic taste?"
"There is a local potter who has been selling for 30 plus years. He has sells all of his work as food safe and dishwasher safe. One of my students bought a black piece, sent it through the dishwasher and it turned blue, we did a 12 hour vinegar test and it turned green."
"Food safety of our product has suddenly come to our attention. The biggest health problem I think we have is crazing (maybe some leaching). We need a way to solve this yesterday."
"I just read on another site that crystal glazed ware cannot be on functional (eat off of) ware. I do not believe this is true. I suspect it depends on the glaze formula. There is a pottery in Maine that does almost all crystal glazes and they are on food dishes."
"I participated in a workshop with .. this past weekend. When he was talking about glazes and demonstrating his techniques, I steeled myself to ask him if he worries about the functionality of his glazes. I figured everyone would laugh at me for bringing up such a subject, but I felt like it should at least be said, given the amount of young student potters in the group if nothing else. As expected he said he didn't worry about that. High fired glazes shouldn't pose any problems, was what he said. "Why is that?", I asked, "Is it because they are fired to such high temperatures that you don't worry?" He said it was. I thought to myself, what does that mean, that if you fire to high heat you kill everything bad -- like germs. I've never known a potter who considers functionality in their glazes. "
"I have large cobalt blue glasses in my kitchen. At night I leave water in one when I go to bed. I noticed a distinct metal taste in the water each morning. I tried putting water in an identical sized clear glass and noticed no metal taste after more than 24 hours. I repeated the experiment with different water(bottled). I got the same result. After 24 hours the cobalt glass reeks of metal taste. Can cobalt glass actually excrete cobalt into water?"
"Could we print your article on leaching in our newsletter. Many members are really concerned about the safety of the pottery they are making."
"Because of media warnings to make people wary about using brightly coloured pottery, I would like to put together some advertising that I can distribute with the work to give people confidence in using brightly coloured hand made pottery. I am wondering if there should be anything further that I could do to have this work tested to guarantee no toxicity in leaching? .. You have no idea how grateful I would be if you can help me or advise me re the above. I am reluctant to do any production until I am satisfied that my work is safe for people to use. "
"I have some questions regarding how food safe some of the commercially bought glazes are. My daughter in-law had bought a new set of imported dinnerware. She decided to try the test and the lemon turned the color on the dish. This ware was labelled Food Safe. Does this mean that is not food safe, or is there a different standard on imports. Some potters I know think that if the commercial glaze says food safe they can use it anyway that they want."
"My partner in crime (wife) is concerned about crazing and we are both concerned about leaching of toxins into someone's dinner...... so we have a keen interest in stability."
"Your comments about the ethics involved in selling functional wares make sense to me, but not to my studio friends. I'm studying ceramics under studio potters (making functional wares) who NEVER test new glazes for durabilty, leaching,etc. (despite? college degrees in ceramic art)."