Martin Howard on mon 30 oct 00
This idea of adding ash to our basic throwing clay appeals to me.
I have a lot of ash and little to do with it, because I fire at no more than
cone 3 and the ash has little effect as a glaze material at that
temperature.
As you know. I do not like calling anything "waste".
Have other Clayarters added ash to their basic clay?
If so, was it worthwhile?
Martin Howard
Webb's Cottage Pottery
Woolpits Road, Great Saling
BRAINTREE, Essex CM7 5DZ
England
martin@webbscottage.co.uk
Khaimraj Seepersad on mon 30 oct 00
Good Day to All ,
Martin ,
the ash added into Amerindian pottery is then fired in the
clay to a low fire - 850 deg.c max - as far as I know .
It is also a fast fire , as the exterior of the pottery is harder
than the inside . Noticeable in their thicker cooking bodies.
This results in charcoal bits in the body .
Fired at a higher temperature , the material goes to white
ash and leaves holes .
Have you tried Pitchers ?
Khaimraj
-----Original Message-----
From: Martin Howard
To: CLAYART@LSV.CERAMICS.ORG
Date: 30 October 2000 4:13
Subject: Re: Amazon clay, Adding ash to clay
>This idea of adding ash to our basic throwing clay appeals to me.
>I have a lot of ash and little to do with it, because I fire at no more
than
>cone 3 and the ash has little effect as a glaze material at that
>temperature.
>
>As you know. I do not like calling anything "waste".
>
>Have other Clayarters added ash to their basic clay?
>
>If so, was it worthwhile?
>Martin Howard
>Webb's Cottage Pottery
>Woolpits Road, Great Saling
>BRAINTREE, Essex CM7 5DZ
>England
>martin@webbscottage.co.uk
Louis H.. Katz on mon 30 oct 00
If its wood ash, make sure it is washed well. The soluble salts will caus=
e no end
of trouble and remove the skin from your hands. If it is rice hull ash, w=
ell just
add it.
But, Don't give up on using wood ash at lower temperatures, just include =
it in
your calculations.
Here is something I worked on for Korat Pottery Company.
Glaze name: Nikom Altered 1
Cone: 2 3 4 5 6?
Recipe: Percent
container Glass 40.97
Wood Ash 24.41
Dankwean Red Clay 7.03 Like a fire clay with 6% iron
Whiting 0.56
Silica 18.94
Totals: 100.00 % 1
Unity Formula for Nikom Altered 1:
0.160 K2O=A0 0.122 Al2O3 1.985 SiO2=A0
0.122 Na2O 0.006 Fe2O3 0.002 TiO2=A0
0.590 CaO=A0 0.013 P2O5=A0 16.3:1 Si:Al Ratio
0.128 MgO=A0
Percentage Analysis:
60.97 % SiO2
6.34 % Al2O3
7.72 % K2O
3.89 % Na2O
16.93 % CaO
2.66 % MgO
0.51 % Fe2O3
0.92 % P2O5
0.10 % TiO2
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