Peter Cunicelli on sat 25 mar 06
Hi everyone,
I just read an article in this month's issue of Pottery Making Illustrated
called "Wood-Ash Glazing at Cone 6" by Harry Spring. As a tip he
recommends sieving wood ash over freshly sprayed glaze.
I fire at cone 10. I would only do the upper third of a piece. My
question is, will this reduce the maturation temp of the glaze? I don't
know anything about ash. One of the reasons i bought my loft was because
of the fireplace. So, I have plenty of ash.
Any information would be greatly appreciated.
Thanks!
Peter
(www.petercunicelli.com)
Dannon Rhudy on sat 25 mar 06
Sieving ash over a glazed piece is pretty common, and
generally does not alter the glaze much. Of course,
if you put it on thick, then it might. But you want to
sprinkle it, more like salting a tomato....
regards
Dannon Rhudy
>
> I just read an article in this month's issue of Pottery Making Illustrated
> called "Wood-Ash Glazing at Cone 6" by Harry Spring. As a tip he
> recommends sieving wood ash over freshly sprayed glaze.
>
---
---
Peter Cunicelli on sun 26 mar 06
Dannon and Lee,
Thanks for the information. I've also received some very helpful hints
privately.
Lee, I'm not planning on making the ash glaze, but instead sprinkling ash
on a piece. This kiln load is pretty much full of tests. I'm going to
try glaze firing a bone dry, paper clay piece in this load as well. Jerry
said it could be done... SO, it'll be on its own top shelf and away from
any other pieces.
Peter
(www.petercunicelli.com)
Elizabeth Priddy on sun 26 mar 06
I hope this isn't too late.
put the piece that you are once firing at the BOTTOM
of the kiln, that way, if it shatters, it will not fall down and on
to the glaze ware where it will stick once the glaze melts.
I learned this when I was teaching kids, all cone 06-05
glaze, same as bisque so both could go in at once. It works
fine, no need to seperate, just keep the bisque low and the
glaze high.
You can even once fire electric and get really good results, the
trick is to candle overnight.
One thing a lot of people just never think about is that most
pottery prior to 20th c. was once fired.
E
Peter Cunicelli wrote:
Dannon and Lee,
Thanks for the information. I've also received some very helpful hints
privately.
Lee, I'm not planning on making the ash glaze, but instead sprinkling ash
on a piece. This kiln load is pretty much full of tests. I'm going to
try glaze firing a bone dry, paper clay piece in this load as well. Jerry
said it could be done... SO, it'll be on its own top shelf and away from
any other pieces.
Elizabeth Priddy
Beaufort, NC - USA
http://www.elizabethpriddy.com
---------------------------------
Yahoo! Messenger with Voice. PC-to-Phone calls for ridiculously low rates.
lee love on sun 26 mar 06
--- In clayart@yahoogroups.com, Peter Cunicelli
wrote:
> I fire at cone 10. I would only do the upper third of a piece. My
> question is, will this reduce the maturation temp of the glaze?
They say a good place to start with wood ash, is to replace
whiting in your recipe with it. Many folks also use a 50/50
ash/clay recipe at cone 10. So that gives us a clue.
I would recommend making a test button and firing your ash in a
glaze firing and see what you get. Use a tile with a depression or
a little plate. You can put the slightly dampened ash into
something like a thimble to make your button. If you want, you could
test washed and unwashed ash. Doing a simply line blend with
different clays might also be interesting.
Good luck!
-
Lee In Mashiko, Japan
http://mashiko.org
http://seisokuro.blogspot.com/
"The way we are, we are members of each other. All of us.
Everything. The difference ain't in who is a member and who is not,
but in who knows it and ho don't."
--Burley Coulter (Wendell Berry)
Ivor and Olive Lewis on mon 27 mar 06
Dear Peter Cunicelli,=20
Each species of plant has a unique mixture of elements in its biological =
composition. A full analysis would show a wide selection from the =
Periodic Table. There will be Na, K, Ca, Mg, Si, P, N, S, Cl, C. for =
certain in the raw material. All of these can survive burning and be =
retained in the ash as Carbonates, Sulphates, Chlorides, Phosphates, =
Nitrites and Oxides. Some of these are freely soluble in water and may =
be washed out if the ash is processed, Some have low melting points. =
When they melt they react freely with Silica or silicates in Clay and =
other surface coatings.
You say you wish to use Raw Ash over an existing glaze. The main =
influential residue in raw ash will be Potassium Carbonate, up to 30% in =
some plant residues. This will melt at 891 deg C (1636 deg F). Then it =
will react with Free Silica to form one of the Potash Silicate =
compounds. The fluid that is created will become an environment for =
further chemical changes as you glaze matures. Other substances in the =
ash, the clay and the applied glaze will influence Viscosity and Surface =
Tension. There are good tables in Hamer and Hamer, "Potter's Dictionary =
of Materials and Techniques" which describe potential changes to these =
physical characteristics, matching metallic oxide with an increase or =
decrease in effect and firing temperature.
Enjoy the journey.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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