Jonathan Kaplan on mon 3 mar 97
There were some postings and inquiries regarding use of Darvan in place of
Sodium Silicate/Soda Ash deffloculation systems...
While the tried and true Sodium Silicate/Soda Ash systems do work, they are
extrememly harsh on molds and lead to premature mold failure over time.
They also have very narrow parameters in establishing correct
defflocuation.
Darvan (available from RT Vanderbilt) is a polyacrylate avaliable in many
formulations, both long and short chained polymers. This material is a far
better additive to a slip than sodium silicate/soda ash, and is more
forgiving. Use of the correct Darvan formulation is essential-there is
Darvan 7 and there is Darvan 611 (same as Spinks Product 211).
I have used Vanderbilts products in the shop for over 7 years now and while
they may produce slower casting times in the molds, they are a far superior
addition for deffloculation.
Jonathan
Jonathan Kaplan
http://www.craftweb.com/org/jkaplan/cdg.shtml
http://digitalfire.com/magic/articles/kaplan1.htm
(aka "Scooter)
jonathan@csn.net
Ceramic Design Group Ltd./Production Services Voice:
970-879-9139 POB 775112
FAXmodem: same
Steamboat Springs, Colorado 80477, USA CALL before faxing
"Arrive on time, tell the truth, be a good listener, and don't
be too attatched to the results. Above all, maintain a sense of
humor!"
Robert Kittel on mon 3 mar 97
We have tried both methods of defloculation. Darvan did seem easier to use
but in a commercial pottery the ease of use didn't outway the advantages of
the sodium silicate/soda ash/barium system. Two things we experianced. We
did not gain any appreciable mold life, (we run 15 tons of clay a week).
While these chemicals are harsh, mold life deterioration is also a product
of the way the molds are filled. The increase in casting time was not an
option. In the Laguna clay catalog, page 29, is an excellent description of
the exact methods used for slipmaking. Both methods are discussed.
Bob
Clay design inc.
>----------------------------Original message----------------------------
>There were some postings and inquiries regarding use of Darvan in place of
>Sodium Silicate/Soda Ash deffloculation systems...
>
>While the tried and true Sodium Silicate/Soda Ash systems do work, they are
>extrememly harsh on molds and lead to premature mold failure over time.
>They also have very narrow parameters in establishing correct
>defflocuation.
>
>Darvan (available from RT Vanderbilt) is a polyacrylate avaliable in many
>formulations, both long and short chained polymers. This material is a far
>better additive to a slip than sodium silicate/soda ash, and is more
>forgiving. Use of the correct Darvan formulation is essential-there is
>Darvan 7 and there is Darvan 611 (same as Spinks Product 211).
>
>I have used Vanderbilts products in the shop for over 7 years now and while
>they may produce slower casting times in the molds, they are a far superior
>addition for deffloculation.
>
>Jonathan
>
>
>Jonathan Kaplan
>http://www.craftweb.com/org/jkaplan/cdg.shtml
>
>
>http://digitalfire.com/magic/articles/kaplan1.htm
>(aka "Scooter)
>jonathan@csn.net
>Ceramic Design Group Ltd./Production Services Voice:
>970-879-9139 POB 775112
>FAXmodem: same
>Steamboat Springs, Colorado 80477, USA CALL before faxing
>
>
>
> "Arrive on time, tell the truth, be a good listener, and don't
> be too attatched to the results. Above all, maintain a sense of
> humor!"
>
Robert S. Bruch on wed 5 mar 97
Robert Kittel mentions that "mold deterioration
is also dependent on the way molds are filled"
Could you elaborate on this?
thank you,
--
Bob Bruch rsb8@po.cwru.edu
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