Monday, April 5, 2010


It is as if my bowls felt my ambiguity concerning them, thus the opening of my second kiln was a bit of a bad surprise. Many of the bowls came out foggy, or turbid. I used Hensen's Transparent Clear Glaze recipe, one that I am mixing and using always and somehow, this time it didn't work well. Although in other times I double dipped half and half of the bowl without any traces; this time it shows very unclear, where the layers were overlapped. Pottery work could be so frustrating sometimes.

My beautiful butterflies are drowning in a milky glaze

so much work, and such a big disapointment

at least on these ones the fogginess is all around

these are of the few that came out great, can't see why?

I did like the rest of the tests with the brushed glazes though. Especially the ones I brushed with Gold Tenmoku. It did make some craters holes, but it was only because it probably didn't work well with the turquoise glaze. The color itself, is very beautiful, I can't wait to see it on a whole pot.

these are the plates with the right recipe of Saphire Blue


Sue said...

Hi Varda,

I think everything turned out beautifully. If I made such amazingly intricate work as you do, I'd freeze at the glazing process because so much can go wrong that's beyond one's control. I don't see the milkiness interfering with the outcome of the pieces but having made this mistake myself many times before, it seems that the clear glaze was applied too thickly which happens when dip glazing - and why I prefer to apply my glazes thinly with a brush. Have you ever tried an airbrush for glazing?

Kim Hines said...

i was wondering about the glaze maybe being applied too thickly too. i used to work in earthenware and often saw the glaze clouding like that where it was applied too thick. though not sure what temp you use. the carved bowls are still lovely, cloudy glaze or not. could you try firing it to a little higher temp to try to clear the glaze up a bit? i seem to remember reading something about being able to do that, but not sure...

i like the painted glaze bowls too, that blue swirly one is very cool. it's interesting how the 2 different styles of work you're making are so very different. i'm absolutely in love with your carved bowls and see them as being those prized pieces brought out for special occasions or on display, not for every day use really. (they look too expensive for that lol). your painted glazed pieces could be used for daily meals i think. :)

Linda Starr said...

Your bowls are beautiful and somehow the cloudiness makes me think of an ancient bowl and the patterns already make me feel that way so I see them as just perfect.

I too was going to suggest refiring to see if the cloudyness will clear up. I brush my glazes on and someday hope to experiment and learn with air brushing.

Kitty Shepherd said...

Hi Varda,
I saw your post then immediately lost my internet and telephone connection for 2 days, it drove me round the twist, then I got it back for a day then lost it again today. That is why I am not posting anything on my blog. Now I am connected again and I hope it stays as I am home alone in Spain with husband flown back to London for a meeting today and tomorrow.
To your glaze; I have has the same thing happen to me and I thought it was devitrification. This is the crystallization of glaze upon cooling. Transparent glazes contain no crystals and are referred to as super-cooled liquids. However if glazes are cooled very slowly crystals begin to form and the resulting glaze is clouded with crystals on the surface which often appears matt, does it look like this? It often happens only on part of the pot. It is avoided for transparent shiny glazes by cooling them as quickly as possible. What are you ambient temperatures where you are at the moment? Might this have an impact on cooling? I wonder if this is the answer, do let me know.

Kitty Shepherd said...

Well I am glad we have cleared up that problem. For anyone reading this thread you said this in reply to my comment:

"You must be so right!!! I have started recently to fire up to 1180 Celsius, with slow cooling, hold 10 minutes at 1180, then, slow cool to 1000 and hold for 15 min, then slow cool to 800. I never did this before with transparent glaze, and never had the problem before, so what you are saying really makes sense. I didn't think about this, because I do not have experience at all, and thought that slow cooling is better, if one doesn't want to fire higher than 1180.
Why I do not fire at 1200- 1220? Because it looked to me, that the glazes looked burnt a little, and also I remember reading somewhere in my books, that slow cooling is a good way to get deeper colors. I am happy that my daughter study pottery in art school; she'll probably know much more than me, and won't do stupid mistakes. Thank you so much Kitty for writing me- I will change the firing program in the coming kiln."

So the answer is to take the kiln up to the temperature you require. I think 1180 is very high for earthenware and it might be this that is knocking back your colours. I fire to 1107 and this is regarded as high, bit I do not know what clay you are using. The reds and oranges don't like the high temperatures. Anyway take the kiln to top temperature and soak for 10 minutes then switch off and let the kiln cool as normal. If you are experiencing very hot weather, after 800 degrees take the bung out. I think you might try a re-fire of ONE of the cloudy pots to see what happens. it may blister and crater but that will be due the re-fire not the new cycle. In Ireland where they make Waterford crystal glass they have to crash cool the mouton glass and that is what gives it its fabulous bright glassy “ping”.
My bedside reading is Frank and Janet Hamer’s “The Potter’s Dictionary of Materials and Techniques” it is very good I recommend it if you can get hold of a copy it has everything you could need to know about pottery.

Kitty Shepherd said...

If you are useing stoneware then your top temperature is right. I am impressed you can get those reds at such a high fire.


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