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Celia UK

Member Since 01 Jul 2012
Offline Last Active Yesterday, 02:48 PM
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Topics I've Started

White Stoneware Low Fire Glaze Mistake - Pinging

02 October 2016 - 11:58 AM

I've just taken a glaze firing out of the kiln - 1080oC (cone 04) transparent glaze on (mostly) a white earthenware clay. I can see that 2 pieces were in fact stoneware, which wasn't obvious after the bisque firing as my other pieces were white earthenware. The two stoneware bowls are pinging like mad and I can see the linear glaze cracks going round the bowls. The glaze can be pretty forgiving at higher temperatures and I'm wondering if these pieces might 'work' if refired to the clay's maturity temperature, or will the glaze fit always be a problem?

Glaze Application - Cracks

16 August 2016 - 04:11 PM

I have just poured the inside of a stoneware cylinder (test piece bisqued to 1000oC) with a transparent glaze that crawled horribly in a previous batch. This is a commercially mixed dipping glaze - very reliable by all accounts! Following advice here and elsewhere I let it stand and drew the excess water off the top. The glaze is now like pouring cream consistency. 100ml weighs 153g. I've poured the inside - about 3 seconds. As it dried the glaze cracked - see photo. What does this indicate? Can I just finger-sand it and dip the outside or am I destined for more disappointment?
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Substitute For Lead Bisilicate

07 July 2016 - 03:01 AM

I have a low fire transparent glaze recipe that makes a nice glossy glaze with a good colour response to various oxides. It has crazed slightly and would be even better for me if that didn't happen.
I know the lead bisilicate helps with the colour response but am not sure about sticking with this as my 'go to' recipe because of the lead.
This is for use on a smooth, white earthenware, sometimes just as a transparent over underglazes or oxide washes, but also as a base with oxide/stain additions.

Can anyone suggest a possible substitute? And if it helps with crazing that would be even better! I know I'll have to re-test, but a starting point would be helpful.
The recipe is -
Lead bisilicate 65
Whiting 10
Potash feldspar 15
China clay 10