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flocculant and deflocculant

updated fri 31 may 96

 

Peter Wilkins/CAM/Lotus on fri 17 may 96

So I finally get my copy of Hamer's Ceramics Dictionary and I figure all I
gotta do is open the book, read the entry, and do what it says. I've got this
glaze that settles real fast, can't dip a mug without needing a stir. I put 2%
benonite in it but it doesn't help.
So now I got the Hamers on my side. I look up Benonite and find that I need to
add some Calcium Chloride. OK, fine. I don't find it listed in any ceramics
catalogs, but the hardware store sells it as crystals. I dissolve some in
water, add it to the glaze, and nothing happens. I mix some more into the
solution, and add more solution to the glaze. Still nothing. So, wondering if
the Hamers have let me down, or if I misunderstood the instructions, I add
still more crystals to the solution and add a larger dollop to the glaze.
Something happens.
The glaze is now the consistency of mocha pudding. I go back to Hamer and
follow flocculant to a left at Zeta Potential, three blocks on I take a right
at Viscosity and get lost somewhere in Thixotropy.

My question is: What can I do to get the glaze back to a usable consistency?
I'm hesitant to simply add more water since intuitively it seems that the
flocculated (deflocculated?) benonite has changed the ratio of solids in the
suspension ( though my reading suggests that this is not the case).

Anyone care to offer an opinion?

Peter Wilkins
Pandemonium Pottery

Louis Howard Katz on fri 17 may 96

Assuming that the glaze doesn't let a significant amount of materials
into solution, you can try the folowwing.
1. mix the glaze with ten time it's normal volume of water.
2. Allow to settle
3. siphon off the water
4. repeat if necessary

This may help. Sounds like too much Calcium Chloride.
Louis

***************************************************
*Louis Katz lkatz@falcon.tamucc.edu *
*Texas A&M University Corpus Christi *
*6300 Ocean Drive, Art Department *
*Corpus Christi, Tx 78412 *
*Phone (512) 994-5987 *
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Richard Boyd on sat 18 may 96

Peter,

Take a small (quart should do) amount of the "stuff" you have, and add a
little (1/4 teaspoon) ebsom salts to it. Good luck.