Roger Korn on sat 28 jun 03
Sam or Mary,
I've done this on a number of occasions. What I do is mix a very thick
mixture of clay and water, so that the mixture has a specific gravity of
1.75 to 1.80 (one liter should weigh between 1750 and 1800 grams). This
will be much too thick to pour into a mold. Then add a deflocculant that
is a mix of equal parts of sodium silicate and soda ash dissolved in
water. You only need add about 1/4 to 1/2% by weight. Stir constantly (a
jiffy mixer on an electric drill works well) and add the deflocculant a
few drops at a time. Quite suddenly, the mixture will thin dramatically.
This is the point at which you have a decent casting slip - one that
will cast to 1/8 to 3/16" thickness in 5 to 15 minutes. Keep stirring
for quite a while, and if thickening occurs, add a small additional
amount of deflocculent.
Roger, in the middle of AZ where we don't get too much fog - I miss the
Bay Area summers. 107 and a good swimmin' hole is as good as it gets.
Sam or Mary Yancy wrote:
>I have been thinking about slip casting a few pottery pieces as a experiment (never done it before). I have my own original piece(s) and I know now to make plaster molds.
>However I don't have any store-bought slip/clay for the clay pour. But I have at least 200 lbs of various cone 6 clay trimmings sitting in a slurry /mud to reconstitute - (normally I dry it out some and wedge and use over).
>My question to the clay art community is: can I use this clay/trimmings for a clay/slip pour and/or what do I have to do to it to make it ok to use - or do I need to go buy some clay slip. Help appreciated. Thanks in advance, Sam in Daly City, CA. (where it was 100 degrees yesterday (and thelast three days) and 59 degrees today + plus heavy fog).
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
>
>
--
Roger Korn
McKay Creek Ceramics
In AZ: PO Box 463
4215 Culpepper Ranch Rd
Rimrock, AZ 86335
928-567-5699 <-
In OR: PO Box 436
31330 NW Pacific Ave.
North Plains, OR 97133
503-647-5464
Sam or Mary Yancy on sat 28 jun 03
I have been thinking about slip casting a few pottery pieces as a experiment (never done it before). I have my own original piece(s) and I know now to make plaster molds.
However I don't have any store-bought slip/clay for the clay pour. But I have at least 200 lbs of various cone 6 clay trimmings sitting in a slurry /mud to reconstitute - (normally I dry it out some and wedge and use over).
My question to the clay art community is: can I use this clay/trimmings for a clay/slip pour and/or what do I have to do to it to make it ok to use - or do I need to go buy some clay slip. Help appreciated. Thanks in advance, Sam in Daly City, CA. (where it was 100 degrees yesterday (and thelast three days) and 59 degrees today + plus heavy fog).
Sam or Mary Yancy on mon 30 jun 03
Thank you for the info - will do. Sam
Roger Korn wrote:Sam or Mary,
I've done this on a number of occasions. What I do is mix a very thick
mixture of clay and water, so that the mixture has a specific gravity of
1.75 to 1.80 (one liter should weigh between 1750 and 1800 grams). This
will be much too thick to pour into a mold. Then add a deflocculant that
is a mix of equal parts of sodium silicate and soda ash dissolved in
water. You only need add about 1/4 to 1/2% by weight. Stir constantly (a
jiffy mixer on an electric drill works well) and add the deflocculant a
few drops at a time. Quite suddenly, the mixture will thin dramatically.
This is the point at which you have a decent casting slip - one that
will cast to 1/8 to 3/16" thickness in 5 to 15 minutes. Keep stirring
for quite a while, and if thickening occurs, add a small additional
amount of deflocculent.
Roger, in the middle of AZ where we don't get too much fog - I miss the
Bay Area summers. 107 and a good swimmin' hole is as good as it gets.
Sam or Mary Yancy wrote:
>I have been thinking about slip casting a few pottery pieces as a experiment (never done it before). I have my own original piece(s) and I know now to make plaster molds.
>However I don't have any store-bought slip/clay for the clay pour. But I have at least 200 lbs of various cone 6 clay trimmings sitting in a slurry /mud to reconstitute - (normally I dry it out some and wedge and use over).
>My question to the clay art community is: can I use this clay/trimmings for a clay/slip pour and/or what do I have to do to it to make it ok to use - or do I need to go buy some clay slip. Help appreciated. Thanks in advance, Sam in Daly City, CA. (where it was 100 degrees yesterday (and thelast three days) and 59 degrees today + plus heavy fog).
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
>
>
--
Roger Korn
McKay Creek Ceramics
In AZ: PO Box 463
4215 Culpepper Ranch Rd
Rimrock, AZ 86335
928-567-5699 <-
In OR: PO Box 436
31330 NW Pacific Ave.
North Plains, OR 97133
503-647-5464
______________________________________________________________________________
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
clayart@DIGITALFIRE.AB.CA on mon 30 jun 03
Also check this page to get an understanding of deflocculation,
specific gravity and viscosity.
http://www.digitalfire.ab.ca/cermat/education/213.php
-------8<--------
Thank you for the info - will do. Sam
Roger Korn wrote:Sam or Mary,
I\'ve done this on a number of occasions. What I do is mix a very thick
mixture of clay and water, so that the mixture has a specific gravity of
1.75 to 1.80 (one liter should weigh between 1750 and 1800 grams). This
will be much too thick to pour into a mold. Then add a deflocculant that
is a mix of equal parts of sodium silicate and soda ash dissolved in
water. You only need add about 1/4 to 1/2% by weight. Stir constantly (a
jiffy mixer on an electric drill works well) and add the deflocculant a
few drops at a time. Quite suddenly, the mixture will thin dramatically.
This is the point at which you have a decent casting slip - one that
will cast to 1/8 to 3/16\" thickness in 5 to 15 minutes. Keep stirring
for quite a while, and if thickening occurs, add a small additional
amount of deflocculent.
Roger, in the middle of AZ where we don\'t get too much fog - I miss the
Bay Area summers. 107 and a good swimmin\' hole is as good as it gets.
Sam or Mary Yancy wrote:
>I have been thinking about slip casting a few pottery pieces as a experiment (never done it before). I have my own original piece(s) and I know now to make plaster molds.
>However I don\'t have any store-bought slip/clay for the clay pour. But I have at least 200 lbs of various cone 6 clay trimmings sitting in a slurry /mud to reconstitute - (normally I dry it out some and wedge and use over).
>My question to the clay art community is: can I use this clay/trimmings for a clay/slip pour and/or what do I have to do to it to make it ok to use - or do I need to go buy some clay slip. Help appreciated. Thanks in advance, Sam in Daly City, CA. (where it was 100 degrees yesterday (and thelast three days) and 59 degrees today + plus heavy fog).
>
--------
Tony Hansen, Digitalfire Corp.
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