ELAINE CARROLL on wed 17 mar 10
Thanks for all the info on red raku glazes. Now I have another =3D
question. What is the best thing to use to keep glazes from settling to =
=3D
the bottom of the bucket? How much should I use for a gallon bucket or =3D
1000 gr batch? I know you gurus out there can give me a good answer. =3D
Thanks, Elaine (don't forget I am an amateur, especially with mixing =3D
glazes, but I do have the MC^6 book)
John Post on wed 17 mar 10
For troublesome glazes that hardpan, I like to use 2% epsom salts
along with 2% bentonite. Add these to the water and stir first before
adding the rest of the glaze chemicals if you are mixing a new batch.
To save a batch that is already a problem, add these ingredients to a
container of water first and mix them, then break up and stir your
glaze batch the best you can. Then add the small epsom/bentonite/
water mix to the bucket and stir some more.
John Post
Sterling Heights, Michigan
:: cone 6 glaze website :: http://www.johnpost.us
:: elementary art website :: http://www.wemakeart.org
:: youtube channel :: http://www.youtube.com/user/MrPostArtTeacher
On Mar 17, 2010, at 12:58 PM, ELAINE CARROLL wrote:
> Thanks for all the info on red raku glazes. Now I have another
> question. What is the best thing to use to keep glazes from
> settling to the bottom of the bucket? How much should I use for a
> gallon bucket or 1000 gr batch? I know you gurus out there can give
> me a good answer. Thanks, Elaine (don't forget I am an amateur,
> especially with mixing glazes, but I do have the MC^6 book)
David Finkelnburg on thu 18 mar 10
Elaine,
I'm sure you've gotten these responses already...
This is more complicated than you know. :-)
Best glazes have at least 10% clay and are dense enough to keep in
suspension. If you have clay in the glaze and it settles, try decanting of=
f
some of the clear water, setting it aside, and testing whether that helps.
Adding ~0.7% (less than 1%) Epsom salts helps. Effect fades with time.
Doesn't do much if there's no clay or bentonite in the glaze.
Adding bentonite, if you can't use clay because of the recipe, works but
don't overdo it. Less than 1% is a good place to start. Dry mix the
bentonite into the other ingredients or hydrate in water for at least 24
hours before adding to glaze. Measure drying time (should be seconds) of
glaze applied to bisque before and after adding bentonite. If your drying
time becomes minutes before gloss goes off glaze surface you have too much.
:-( 3% bentonite is probably an absolute maximum if it's good bentonite.
Vee-gums are similar, even more potent.
These methods can be used together, but not the maximum of each at the
same time. If you use Epsom salts and bentonite, use less of each to start
and test.
Hope this helps!
Dave Finkelnburg
http://www.mattanddavesclays.com
-----------------------------
Date: Wed, 17 Mar 2010 11:58:09 -0500
From: ELAINE CARROLL
Subject: Suspending Glazes
....What is the best thing to use to keep glazes from settling to =3D
the bottom of the bucket? How much should I use for a gallon bucket or =3D
1000 gr batch?
Ron Roy on fri 19 mar 10
Hi Elaine
A great help is subbing in ball clay for any kaolin to help suspension
- ball clays have less alumina in them then kaolins so you have to add
more ball clay to get the same amount - and if that does not work then
bentonite works better with ball clay than kaolin. And if that doesn't
work adding the epson salts works better with ball clay and bentonite
than with just kaolin.
Best to do the substitution using glaze calculation - when you add
more ball clay you get more silica than you need so you have to take
some SiO2 out.
Send me the recipe and I'll show you how.
RR
>
> Date: Wed, 17 Mar 2010 11:58:09 -0500
> From: ELAINE CARROLL
> Subject: Suspending Glazes
>
> ....What is the best thing to use to keep glazes from settling to =3D
> the bottom of the bucket? How much should I use for a gallon bucket or =
=3D
> 1000 gr batch?
>
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