I just did my first kiln run. I didn't realize that that I should have let my cups sit in the glaze longer than I did. My glaze is pretty thin. Instead of getting a nice smooth texture, I can still feel the toothy sandyness of the clay under the glaze.

Could I re dip my pottery and add a transparent clear coat over the already fired last glazing that was too thin?

I'm guessing that I'll have trouble getting the glaze to hang onto the already fired surface. Has anyone added glaze to an already glazed item? How does it turn out?

Also, I decided to do an experiment and fire some streaks of cone 04 glaze painted onto cone 6 dipped glaze and porcelain. I like how the 04 smeared out, but now I find myself wondering if the low fire glaze is still foodsafe after being considerably overfired.

Finally, would a cone 6 glaze be food safe if fired to 04? I boneheaded a cone 6 glazed piece in a bisque run and realized I put the wrong thing into the bisque run. The silicate in the glaze seemed to still melt and flow. It's glossy and the glaze developed color. Is this accident food safe? Can I refire it to cone 6 to finish the job?

All the glazes and clay I've been using has been described as food safe by the manufacturers. I'm just not sure if the metal oxides used are still properly encapsulated by the silicates or whatever pixies go into making metal oxide pigments food safe.

I've done some leaching tests, but I can't say I trust the results (no color change) without some spectroscopy which isn't a resource I have.