ImogenB

Would you otherwise think this glaze would be food safe?

How about adding 10% more china clay so the new ratios are Potash 27 quartz 33 whiting 21 china clay 19 do you think this would work ?

Hi can anyone offer any further advice? I made this glaze and fired it to 1280oc. It is changing colour when i put in lemon over night to test for leaching, as you can see there are white speckles where the cobalt is no longer. The recipe is: Potash Feldspar 30g Quartz 36g Whiting 23g China Clay 11g + Cobalt Carbonate 1g Can anyone help to why this is still leaching?

Hi this looks great, thank you. I hadn't come across this recipe yet.

Yes I'm not sure that Glaze is suitable, I think i'll avoid using Barium. Yes it does have a broad firing range. I have an electric kiln, so it'd be an oxidise firing. I'm from the UK so using Fahrenheit isn't natural to me, so i'll use Celsius, but I usually fire to 1260oc.

Brandon, Thanks for your reply. I was wondering if it was stain. I'm yet to test one out, I shall get experimenting. This is the work of Helen Levi, I would think she tests her work to see if it's food safe, so i'm sure it can't be saturated cobalt as that wouldn't be safe. And thanks for the extra tip about amounts, i'll make sure to larger amount when ordering.

Hi Min, Thanks for your helpful response. I am firing to cone 8 to help the longevity of my kiln elements, my clay vitrifies from cone 6. The liner glaze is a good idea, but i am still worried i'd need excessive cobalt to achieve this and therefore would still be not food safe. I have just ordered the book, thank you for the suggestion.

I'm a new potter, and looking into making my own glaze. I'm concerned about how to make such a bright glaze on a stoneware body, most likely firing to cone 7/8 and that is this bright in colour AND most importantly food safe. I'm learning the chemistry behind it but ingredient suggestions might be helpful or just any help.