[Clayart] Replacing bentonite

[ronroy at ca.inter.net]

Hi Jeremy,

My general rule about bentonite is:

If a glaze has less than 10% kaolin bentonite may be needed to keep  
that glaze in suspension long enough while glazing pots. That’s  
because kaolins are not very good suspenders especially if there is  
any deflocculation going on.

First I would swap out the kaolin and replace with ball clay using  
calculation of course. If that would not work then add 2% bentonite.

There are advantages to both ball clay and bentonite. They both add a  
toughness to dried glaze (anti powdering) and glazes dry slower after  
application.

There are many published glazes that do have some bentonite but may  
not need it. Yours may be one of those. If you send me the recipe I  
can give you my opinion.

In some cases a glaze may be hard panning because of the local water  
or perhaps a material that is leaking sodium into a glaze over time -  
like neph sy.

In the first case using a pure form of water will correct the problem.  
In the second case adding some flocculant like Epsom salts will work -  
use very little Epsom - anyone who wants my technique for finding out  
how much to use just ask.

Anyway - happy to give you an opinion.

RR



Quoting Jeremy Keala Ceramics via Clayart <clayart at lists.clayartforum.com>:

> Hello,
>
> I?m starting to work on creating a Kuan crackle glaze. My starting recipes
> have bentonite in them and I don?t currently don?t have bentonite in my
> workshop and would like to keep it that way otherwise I just keep adding
> new materials all the time to my list of raw materials.
> Would you have any suggestions how to go about replacing bentonite in a
> glaze ?
> Thanks and all the best,
> Jeremy
>
>
> --
> *Jeremy Keala Ceramics*
> www.jeremykeala.com
> Instagram : @jeremy_keala_ceramics
> <https://www.instagram.com/jeremy_keala_ceramics/>
> +33 (0)6 59 96 92 54
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Ron Roy
ronroy at ca.inter.net
Web page ronroy.net