Laguna glazes & Barium

[HIgaki]

Hi. Our local Potter's guild has recently discovered that most Laguna Moroccan Sand glazes contain barium. I've contacted Laguna to see if anyone has had them leach-tested for barium, but have gotten nowhere. Has anyone out there done any leach testing on these glazes? I realize it is not required for the ASTM food-safe-designation that Laguna has for these glazes, but I sure would like to know! Thanks!

[Andy Clift]

I don't know the definite answer. To start though your could do your own simple leach test. Its a test I remember reading about in a book by John Hesselberth the author of Mastering Cone 6 Glazes: Improving Durability, Fit and Aesthetics. Place a slice of lemon on the glazed surface and after a day check to see if the color or surface sheen has changed where you put the lemon slice. If it has changed your glaze likes to leach.