Yannick Evenas on sat 23 jun 07
Hello,
someone gave me a recipe for a clear glaze to use with mason stains
(cone 6), and after some test tiles, I noticed that the glaze is
slightly running, accumulating in the bottom inside and outside,
leaving the rim with almost no glaze coverage.
I am using virginia dogwood clay (white clay).
Here is the recipe that I used for the clear glaze:
Whiting 16%
Gerstley Borate 18% ( I used Gillispie borate instead)
G-200 Feldspar 40%
EPK 10%
Silica 325 16%
+ mason stain 10%.
What need to be changed in order to stop the running to occur?
Would this recipe work better?
Gillispie Borate 50
EPK 20
Silica 325 30
If neither of the above recipe work, could you suggest one that work
well?
Forgive my lack of knowledge in chemistry, I am simply an
enthusiast that loves wheel throwing.
Thank you.
Ron Roy on sun 24 jun 07
Hi Yannic,
The first glaze looks OK but it may be the stain that is melting it too much.
The expansion of that glaze is high so I expect it is crazing as well.
I would recommend doing a small test batch - like 500 grams - just to make
sure you did not make any mistakes in weighing. If it still slides then add
more clay to stop the moving - try 2% and 4% more EPK.
The second glaze has a pretty low expansion - I would try adding them
together for a new glaze and if it slides add more EPK to stabilize it.
Let me know if you need help with all this - RR
>Hello,
>someone gave me a recipe for a clear glaze to use with mason stains
>(cone 6), and after some test tiles, I noticed that the glaze is
>slightly running, accumulating in the bottom inside and outside,
>leaving the rim with almost no glaze coverage.
>I am using virginia dogwood clay (white clay).
>Here is the recipe that I used for the clear glaze:
>Whiting 16%
>Gerstley Borate 18% ( I used Gillispie borate instead)
>G-200 Feldspar 40%
>EPK 10%
>Silica 325 16%
>+ mason stain 10%.
>
>What need to be changed in order to stop the running to occur?
>
>Would this recipe work better?
>Gillispie Borate 50
>EPK 20
>Silica 325 30
>
>If neither of the above recipe work, could you suggest one that work
>well?
>Forgive my lack of knowledge in chemistry, I am simply an
>enthusiast that loves wheel throwing.
>Thank you.
>
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Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Dave Finkelnburg on thu 28 jun 07
Yannick,
If your question has already been answered several
times to your satisfaction, please forgive me for
butting in. It's hard for me to keep track of ClayArt
these days.
Your question is a common one, and a good one. If
you want to explore your glaze more, I would do a
simple line blend between your glaze and the same
glaze plus 10% kaolin and 5% silica. It should not
run as much but may not cure the crazing.
The 50% Gillespie Borate version will probably be
even runnier.
Good potting,
Dave Finkelnburg, in Idaho, where the
ClayArt forecast remains, fair to partly unreliable...
From: Yannick Evenas
someone gave me a recipe for a clear glaze to use with
mason stains
(cone 6), and after some test tiles, I noticed that
the glaze is
slightly running, accumulating in the bottom inside
and outside,
leaving the rim with almost no glaze coverage.
I am using virginia dogwood clay (white clay).
Here is the recipe that I used for the clear glaze:
Whiting 16%
Gerstley Borate 18% ( I used Gillispie borate
instead)
G-200 Feldspar 40%
EPK 10%
Silica 325 16%
+ mason stain 10%.
What need to be changed in order to stop the running
to occur?
Would this recipe work better?
Gillispie Borate 50
EPK 20
Silica 325 30
____________________________________________________________________________________
Boardwalk for $500? In 2007? Ha! Play Monopoly Here and Now (it's updated for today's economy) at Yahoo! Games.
http://get.games.yahoo.com/proddesc?gamekey=monopolyherenow
Yannick Evenas on fri 29 jun 07
Thank you both for your replies.
I will first try Ron's suggestion to mix both glazes to make a 3rd one.
I figured out how much to add to all my little baches and I will give it a
try.
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