Dan Saultman on sat 25 nov 06
I have a bag of soda ash has become hard. I have read that soda ash
absorbs water and should be kept in a plastic bag. However, does this
"hydration" caused a difference in performance? I recently tried a
shine glaze that was supposed to be red. It turned out matt white with
a slight crackle pattern. It looks like a shino but is way off target
for the color I wanted. Is it possible that this soda ash problem was
the cause?
Dan Saultman
Inua on sun 26 nov 06
Soda ash is Sodium Carbonate.
Baking Soda is Sodium Bi-carbonate.
Soda ash, if not sealed in a water tight container, will in time convert
to Sodium Bi-carbonate.
Soda Ash is more basic than is Sodium Bicarbonate, while Sodium
Bicarbonate is more acidic than Soda Ash. The two sodium compounds do
not perform the same.
Regards,
John Rodgers
Chelsea, AL
Dan Saultman wrote:
> I have a bag of soda ash has become hard. I have read that soda ash
> absorbs water and should be kept in a plastic bag. However, does this
> "hydration" caused a difference in performance? I recently tried a
> shine glaze that was supposed to be red. It turned out matt white with
> a slight crackle pattern. It looks like a shino but is way off target
> for the color I wanted. Is it possible that this soda ash problem was
> the cause?
>
> Dan Saultman
>
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Lee Love on mon 27 nov 06
On 11/26/06, Dan Saultman wrote:
> for the color I wanted. Is it possible that this soda ash problem was
> the cause?
Can yo share a photo? With Wirt type shinos, an iron clay body
helps with red color. Japanese shinos use a white clay body,
sometimes with iron slip decoration, and they still get red on the
white body. I believe their shinos had more alumina in them and the
red comes from small amounts of iron in the clay in the glaze and its
reaction with alumina.
Also, your reduction has an effect. Show us a photo and it
will help us figure it out.
I don't think it is you soda ash, but you can always add a
little bit more if you think it is heavy with moisture.
--
Lee in Mashiko, Japan
http://potters.blogspot.com/
"Let the beauty we love be what we do." - Rumi
"When we all do better. We ALL do better." -Paul Wellstone
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