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Celia UK

Member Since 01 Jul 2012
Offline Last Active Yesterday, 05:24 PM
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Topics I've Started

Glaze Stoneware Or Earthenware?

21 July 2014 - 03:49 AM

In amongst a batch of ceramic materials & equipment I bought from a potter who was going travelling are two buckets of mixed, liquid glaze. One is a 'matt turquoise blue' the other 'black'. This was a hurried purchase as the young lady was leaving the country the following day and I'd already taken up an hour of her time sorting through her garage! She told me that the black was very runny, and to be careful, and it is labelled as such. I don't know if these are earthenware or stoneware glazes, they were her own mixes. A couple of questions. ( I do plan to test, test, test. ) I currently use a smooth white earthenware, fire in a small electric kiln., glazes usually to 1060/1080oC

1 - what will happen if they are stoneware glazes and I use them on white earthenware firing to earthenware temperatures.

2 - as I already know the black is runny, other than only using it on a rim and expecting it to run, is there anything I can add (without having any idea of the original recipe) that will make it less runny?

3 - what would happen if Earthenware is fired above the recommended temperature? E.g. If I bisque an earthenware piece to 1000oC then glaze to a stoneware temperature?

Many thanks, in anticipation.

Treating Rust On Kiln Lid

18 May 2014 - 03:43 PM

I have a small amount of rust on the outer edge of the vent hole in my kiln lid. Some tiny flakes fell into the kiln & on to a white pot on the top shelf in the last firing - spoiling the pot. Does anyone know if Hammerite would be ok for treating this? Not sure if available outside the UK, but it can be painted directly on to rust once flakiness is brushed off. I've used it on the outer casing of my small electric kiln, but not sure if it can withstand the heat coming up through the vent hole. Does anyone know how hot this part is likely to get during firing? Is there a specialist product for this?

Transparent Glaze For Stoneware

16 March 2014 - 03:16 PM

Have been using white earthenware to date, but decided to try some smooth, speckled stoneware (Valentines Special Fleck 1150 oC - 1280 oC). If I fire this to within the stated temperature range, could I use a lower firing transparent glaze or MUST I invest in a transparent that has a range that matches that of the clay?

Cracks When Refiring

25 December 2013 - 10:55 AM

Having just installed a digital controller to overcome glaze cracking I have had more success with smooth white earthenware bisqued to 1000oC and glazed with transparent glaze to 1100oC. However, after a wax resist 'accident' in my studio (don't ask!) I had 2 pieces which had clearly been splashed with wax and the glaze had not taken in small areas. Apart from this, the rest of the glaze was fine. I touched up the bare spots and refired in the next firing. It was ramped 100o per hr to 300oC then full to 1080oC with a 15 minute soak. Both pieces now have a long crack spiralling around them. Other than the wax resisted spots they were fine after the first firing (to 1100oC). The other pieces with the same glaze, in the firing were fine. I don't know why this would happen with a second firing, to a slightly lower temperature. Any ideas?
Not sure if the pics show the problem clearly.

White Glaze Too Shiny

14 October 2013 - 01:30 PM

I have some glossy, white zirconium glaze (fires at 1030 - 1120 degrees c). It is too white, and too glossy for my purposes. Can anyone suggest any additions that would tone it down a bit, in one or both respects?
I am using studio white earthenware and fire to cone 04 in my small electric kiln. The attached photo shows the finish. Many thanks.