Thursday, September 9, 2010

Ash Glaze

40% ash of the leaves from yard.
Eletric kiln, 1250ºC.
27 cm (or app 10.6") diam.


  1. Muito interessante imagem de seus estudos.

  2. This is a beautiful piece; can you tell me more about using ash in an electric kiln. Do you mix the ash into a glaze? I love using what is nearby in my work and this is something I might like to try.

  3. Tks for your visit Virtualkid!

    Linda, as like you I try nearby things also! Well...First I made small tests just to see how my ash melt. Then I started to try using calcined ash in 10,20,30 and 40%, mixed with previous glazes I have. I had good results with a clear glaze and glaze on the plate at photo. Please, ask if you would like to know more. Sometimes is hard to me to explain in english this kind of experiment, but I will try hard! You can write to me in too.

  4. Hi Acacia, thanks so much. So for the piece above is that a clear glaze with the calcined ash? I found out I can get rice hulls at a beer making supply and I will get some tomorrow and make some experiments like you have. First I will burn the rice hulls and then gather the ash and sieve and put into some glazes and see what I get. I have heard rice hulls are considered a hard ash, and make some really good results in glaze but I know nothing about glaze chemistry, I just try things from intuition and a little amount of knowledge, but I believe sometimes taking a risk makes for some good results.

    I did such experimenting with my barrel firings in the past. I am gathering supplies to do a barrel firing again where I put bisque ware with red iron oxide, copper carbonate, and salt into a salt soaked burlap bag tied up loosely, place in a metal barrel and fire with split hardwood, wood shavings, and straw. I have so many ideas and not enough time to do them all. Thanks ever so much for the information.

  5. It´s my pleasure Linda! And sorry, I didn´t explain well. No, the plate above is with another glaze, but I had good results with the clear glaze too. Ok? I use to wash two or tree time the ash (be careful, the ash is caustic, use gloves!), sieve, let it dry and than I calcined it. I tried the ash with Feldspar and some ball clay, equal parts, and had nice results in the gas kiln. But I had better results in eletric kiln in the way I´m telling you (glazes with ash, not exactly a ash glaze). Another way, is to try a tri-axial blend with the ash, one glaze and another material of your choice: clay, for exemple. Rice hulls is really hard, rich in silica (about 67%), potash, phosphorus pentoxide, etc. Maybe you could try the rice hulls with a melt glaze. Well...the soil, climatic conditions, the choice of the part of the plant, impuritys, all makes the chemical structure of an ash complex and surprising. I really love glazes and I´m always trying some think new.I have lot of doubts too, but if I can be of some help count with me. :)

  6. Thanks, how do you calcine the ash?

  7. Olá Acácita,ficou lindjo tutti

  8. Hi Linda, I put in a bicuit pot and calcine at 900ºC. With the purpose of removing some organic residues, water or other volatile material.

    Sossô... Estava com saudades de vc!!! Que bom que apareceu. Bjssssss.

  9. Thanks, good to know; I got volcanic ash today instead of messing with the rice hull ash.


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