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problem throwing clsay with bentonite

updated tue 8 may 01

 

karen gringhuis on mon 7 may 01


Annabelle -

Bentonite and macaloid are added to porcelain clay
bodies to increase plasticity. Since they expand
greatly as they absorb water, they MUST be blunged in
water and allowed to soak (preferrably overnight)
BEFORE being mixed into the clay body. I would be
very surprised if your supplier did this. (I've found
only one supplier who would even listen and consider
doing it for me )

Mixing in dry macaloid (and probably also bentonite)
results in a micro-bubble porous consistency of the
clay which no amount of re-de-airing pugging or
wedging can get out. It's like trying to wedge a
marshmallow.

IF IF IF this is your problem, I suggest testing the
ff solution:
Cut some of the clay into lumps and soak it in water,
then blunge it to the consistency of pudding. Let it
sit overnight so that ALL the particles are soaked and
you have a noticeable layer of water on top the clay
in your bucket. Skim off this water, then pour the
pudding out onto plaster bats to stiffen up. Wedge
and throw it and see how it goes.

If this solves your problem, you should have very
plastic throwable clay. This approach is sometimes
used to get really plastic clay from a virgin fresh
batch which has had no time to age.

If you try it, please let me know your result.

=====
Karen Gringhuis
KG Pottery
Box 607 Alfred NY 14802

Personal e-mail to:
KGPottery@hotmail.com

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