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fayechristian

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About fayechristian

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  1. White glaze turning yellow

    I love this forum! Thanks for the replys all of which are great ideas. I'd like to meet one of these 'glaze doctors' This is a picture of the piece which pushed me over the edge hopefully you can see the beautiful translucent white glaze and the toxic yellow. Here are some images working well, once the clay body shows through it the overall look is off white but not normally yellow. http://isleofmanpotter.blogspot.com/2012/06/sneak-peek-shh.html?m=1
  2. White glaze turning yellow

    Please help I have a white glaze that randomly turns yellow. I can use the same glaze for a whole kiln full of work and some pieces turn out snow white while their neighbour is totally toxic yellow. The recipe is: Potash Feldspar 33 Talc 21 Quartz 16 China Clay 15 Whiting 12 Zinc 3 + Titanium dixide 3 Tin Oxide On earthstone ES160 special clay I fire to cone 9 in an electric kiln with a ventsure extraction system. I bisc to cone 06 - if that information can be of any help? My own theories have been: Contamination from chrome fumes? but it still happens even when there's not chrome in the kiln. The other glazes I use are iron or copper based. Patches of reduction? but it happens to one pot and not it's neighbour some times and in relatively empty kilns some times too. It also happens in different areas of the kiln. I'm not ruling out thickness of application either but it's not the clay showing through it's a sort of bright toxic yellow fog in the glaze, it's also not as shiny as the white. Help/ideas/theories/general musings welcome
  3. I hope this isn't bad manners but I've just realised this would be better posted in the Clay and Glaze Technical forum but I can't see how to delete this post, so now it's double posted, apologies! Please help I have a white glaze that randomly turns yellow. I can use the same glaze for a whole kiln full of work and some pieces turn out snow white while their neighbour is totally toxic yellow. The recipe is: Potash Feldspar 33 Talc 21 Quartz 16 China Clay 15 Whiting 12 Zinc 3 + Titanium dixide 3 Tin Oxide On earthstone ES160 special clay I fire to cone 9 in an electric kiln with a ventsure extraction system. I bisc to cone 06 - if that information can be of any help? My own theories have been: Contamination from chrome fumes? but it still happens even when there's not chrome in the kiln. The other glazes I use are iron or copper based. Patches of reduction? but it happens to one pot and not it's neighbour some times and in relatively empty kilns some times too. It also happens in different areas of the kiln. I'm not ruling out thickness of application either but it's not the clay showing through it's a sort of bright toxic yellow fog in the glaze, it's also not as shiny as the white. Help/ideas/theories/general musings welcome
  4. Gold Lustre and Alkaline Glaze

    Thank you all! I've never used the forum before but it's been amazing to get responses. I will head straight off to the library to try and find the books you have suggested. Thank you Johanna for taking the time to reply to my post in such depth, what a great answer. It's brilliant to get a response from someone who clearly knows a lot about the subject. I've just ordered a copy of the book you suggested from amazon, thank you. It's also really reasuring to know that what I've found is well documented and it's not something I'm doing wrong, its just a lack of knowledge, which I can improve on. I fire to 1260.c for a normal stoneware firing and as I couldn't find much written about lustre the first time I used it, I cobbled together what I could and punted for 800.c lustre firing with a 10 minute soak to even the final temperature. I have always had good adherence of the lustre to the glazed surface except for the odd blob where I presume it was too thick and burned away. I might try 780.c and no soak to see if it reduces the change in the glaze colour of the glaze. I really appreciate all of you help! Faye
  5. I have just started experimenting with Gold and Platinum Lustre in liquid form. I have found it difficult to find much written about the topic and I wondered it anyone could give me some advice. I remember from college that it should not be used on over an alkaline glaze but I do not know how to identify an alkaline glaze. I would also like to know why it shouldn't be used on an alkaline glaze. I work with a limited pallet of 4 stoneware glazes, a copper green, a copper blue, an iron brown and a chrome pink. I have experienced a few different issues, one of which is a dulling of the glaze on the whole pot, the copper green goes much darker after a lustre firing and the Iron brown turns nearly black while the copper blue and chrome pink do not change at all. The other issue is I get a very matt gold surface on both of my copper glazes, neither of which I would call matt glazes. But a high shine on the iron glaze and chrome pink. Would love any words of wisdom
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