Patchy glaze

[Finn Ewins]

Hi, 

So I just opened my glaze fire this morning and saw on the inside of this teapot the glaze had pulled away in a couple of spots.

First of all, why did this happen and can it be prevented?

And secondly is this still okay to drink from? If there’s very thin or no glaze in those spots does it make it unsafe?

Thanks

[Min]

This is glaze crawling, happens for a few reasons but in this case it looks like the glaze was applied to heavily. Other reasons for crawling are dirty bisque (hand lotions/oils etc on clay) or a high shrinkage of the glaze from materials within it having high loss on ignition.

As long as the clay doesn't weep from too high an absorption the teapot will be fine to use.

Nice looking teapot.

[Finn Ewins]

What does weep mean?

[PeterH]

1 hour ago, Finn Ewins said:

What does weep mean?

To leak slowly.

A quick test is to fill the teapot and leave it on a paper towel overnight. The towel should remain dry.

[Bill Kielb]

Just to add to @PeterH I have left vases for several days for that really tiny leak. Nothing worse than giving someone a vase they use at work and after several days they tell you their vase leaked …… on their desk! No harm in testing longer.

Edited Sunday at 05:53 AM by Bill Kielb