I am sorry again I thought this group was only for stained glass discussions and not about the chemistry als I realy don´t know much about the computers and the internet yet. Sorry again for it.
But it seem like the problems are known thanks for for your great "Know How" Henry I did not know its realy known like this Carefull with the powders if you wanna stay healthy. I think the dangers of glass and working with it should be posted more often to let the kids know better about it .To me it seems like they forgetting as soon they working with the glass and they messing around with this stuff
Keep them informed make up datasheeds like we have to do in ceramics! for every luster or claze is a serious datasheet for safty absolutely necessary!
One more thing Kugler claims their colors are lead free and this is the point !!!!