Monday, January 7, 2013

Ash glazes in time of potter’s life

Ash glazes becomes part of wood firer’s life, each seem to define curtain period of potter’s life as over the time one finds that when it comes to ash glazes each batch is original. It can be made from one plant and still there is no guarantee the glaze will be same.

We had this great ash glaze from Japanese knotweed. This plant is listed by the World Conservation Union as one of the worlds 100 worst invasive species and we had it on our property, when we brought it - The only working way to get rid of this all killing and rapidly spreading weed is to cut it, burn all what was cut and keep on spraying all that grow and if necessary again cut it and burn it. After first burn we had quit good amount of ash to work with, the glaze (just wash ash with water) was amazing, our technical porcelain love it. It runs a bit, so Petr accommodate this “skirt” to his teapots to catch drips. It lasted us about 2 years. 

The next batch from freshly grown Japanese knotweed was much smaller and also much different, it run a lot and was more rather greener than golden green. There surely will be time in future, when we again will work with this weed ash, but it did not happened right away, because different ash glaze entered our lives, this time hay ash. Our friend cuted meadow high in mountain for the rare plants to grow again as they did in past, when those meadows were cut every year. As it was high in mountain and no farmer living close wanted the hay, they had to burn it – their car almost couth fire as they did not realized the ash was still warm enough to ignite. So we received very wet (from puting the car fire out) hay ash with parts of burned blanket in it with its own story already. And this glaze was just miraculous – milky yellow glaze with crystals loving almost every clay, we use. It lasted also more than two years. 

Then another hay ash entered our lives, it waited not washed for a while until its time came. It is very much different from the first hay ash we had, more transparent, less crystals forming, but it has this great visual difference when applied in different thickness and this wooden like natural look on one of our stoneware, that we decided not to play with it, but leave it as it is and enjoy its properties.

Different approach we took towards our nuka glaze (usually we mix nuka: 600g of custar feldspar Poběžovice, 400g of silica and 500g of wood ash). This glaze has great look on our stoneware clay Dorda (stoneware clay with addition of iron scaling). Thick, milky fine blue, subtle and not too yowling glaze. When we used new wood ash it changed its properties to more grey, more running, less milky glaze. We add silica (recipes is always just a guide line, no need to worry). So we are back now to our loving, our kind of blue version of this glazes now.

There is walnut shells ash waiting to be washed and tested to see what nature can offer in its unique composition, so perhaps the TIME OF WALNUT ASH is comming soon...


  1. Very intersting to see the different glazes. As an aficionado of ash-glazed ceramics I'm looking forward to see more works from you. I like the yellow glaze on dark ground.

    1. Thank you, I am sure there will be some interesting ash glazes in future, nature is amazing in that way.

    2. Congratulations on the Blog! Looking forward to seeing the Walnut Ash glaze!

  2. Beautiful work. Love that first teapot lovely. I made some porcelain using grolleg. Any experience with glazes on that type?

  3. Thank you, if I understand correctly grolleg is kaolin, the clean type, which makes porcelain translucent. We use Limoges porcelain TM10, which is translucent and here Francouzký porcelán- Limoques TM 10) is album of photos showing this type of clay in our firing. Also from ash glazes the Japanese knotweed and our first hay glaze was always lovely looking on this type of porcelain.