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03 Lead Free Glaze


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#1 Jupiter

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Posted 31 December 2010 - 09:07 AM

Can anyone help with a low fire clear (03) glaze recipe that looks rich and smooth and well behaved and tolerant to one learning from experience that glazes need careful understanding.

I am currently using a white finely grogged stoneware for some cups, which take a commercial satin glaze very well on the inside, but leaves the outside rough and patchy, as if the oxides I use for decoration sheds the glaze on the outside but not the inside, or concave and convex sides. I am bisque firing to cone 05, built up heat slowly and soaked for an hour.

Help would be appreciated

Gwen

#2 Marcia Selsor

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Posted 03 January 2011 - 03:20 AM

If you are using a stoneware clay, shouldn't you be using a stoneware temperature glaze?
If you prefer to fire to ^03 you would be better off with an earthenware or low fire white clay.
A ^03 glaze on your white stoneware is going to have problems. Read the "Pinging" thread.
Marcia

#3 Jupiter

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Posted 03 January 2011 - 05:16 AM

Thankyou Marcia,

The background to this choice of glaze is: I started with white earthenware but problems with shivvering were so bad I gave up on it.

You are right I should be using stoneware glaze, but I've only switched to buff and white stoneware because I've seen beautiful 03 e/w glazes work well.

My stoneware cups are lovely inside as I said but only scratchy on the outside. I've been using them in the microwave every day for a month and watching closely but they seem to be ok. I have an old kiln, so if this experiment doesn't work it will have to be back to terracotta with white slip. Unless there are any other suggestions for the stoneware glazing. thanks I will look into pinging.

gwen

#4 Jupiter

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Posted 04 January 2011 - 06:20 AM

The stoneware clays I am using have a wide firing range, so they accept an 03 glaze. I think it has potential for useful domestic ware, If I can make sure they are durable. There is no pinging yet, but I am currently doing the test of soaking in strong tea for 24 hours to show signs of crazing.

Meanwhile I would still appreciate any tried and tested 03 earthenware glazes that are easy to apply, and smooth out well at 03, so I can try them on my wide range stoneware

thanks Gwen

#5 TheSmartCat

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Posted 04 January 2011 - 09:29 AM

I have been using the following glaze on both white earth and terra cotta for many years. I have no idea how it will work on stoneware. You may want to explore various white earth bodies as it sounds like there was a bad fit between body and glaze. Remember that not all white earth bodies are created equal.

Ian's Clear:
Frit 3124.........80
EPK.................10
Neph Sy..........10
Bentonite..........3

Applied thinly this is a shiny stabile glaze at ^04-03. Ian uses it as a thick semi-matt glaze, adds 3...lithium carb, & 1...cryolite, or all lithium carb.....4.

Watch out for gerstley borate in clear glazes on white bodies. It tends to yellow.

Hope this at least gives you a starting point.......s

#6 Jupiter

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Posted 06 January 2011 - 09:44 AM

Thank you Smartcat, I will try that recipe on my remaining white earthenware, and do some samples. Thanks to your comment that not all white earthenwares are created equally I think I will try another batch from a quality supplier.

Have you got images of your earthenware pieces?
Gwen




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