Hank Ray on mon 10 aug 98
Hello Glaze Gods!
Here is a recipe... that is used at an art center for student work.....
i would like to figure out how to make it with out the barium....
(for one reason, it is the only glaze with barium and the supply is running
low)
plus all health stuff...... many good blessings go to those that help....
DUNHAM ^10
Blue/rutile blue .. glossy
Custer fieldspar.....40
whiting........11.2
EPK......6.4
"Barium".....11.2
Silica....24
RIO.....4
Copper Carb......0.4
Rutile.......4
Thanks in advance...
Hank in the state stolen from the native americans.......
Robert Wilt on wed 12 aug 98
I mixed up your glaze (or the version I had) about
this time last year, using a 75% strontium substitution.
It looks good to me - I've used it a few times without
any problems. Here is the recipe I use:
Dunham's Blue
-------------
c/10 Reduction
Custer feldspar 35.46
Whiting 12.53
EPK 7.09
Strontium carbonate 9.46
Flint 35.46
--------
100.00
Red iron oxide 3.55
Copper carbonate 0.47
Rutile 4.26
Bentonite 2.00
Epsom salts 1.00
Your version has about 9% more custer than mine,
about 9% less flint, and about 0.9% more RIO,
otherwise they are almost identical.
bob wilt
p.s. For those not familiar with this glaze - it's a
rutile blue, tends to the dark side. The original recipe
I started from (with Barium) came from Creative Arts
in New Haven. I don't know who Dunham is, though!
Ron Roy on mon 17 aug 98
Hey Hank,
I'm a little late with this but, not too late, I hope.
First - the total on your recipe is 101.2 - have I got the right recipe?
My calculation of the original.
Cone 10 DUnHAM with Barium.
-----------------
CUSTER SPAR......... 40.00 39.53%
WHITING............. 11.20 11.07%
EPK................. 6.40 6.32%
BARIUM CARB......... 11.20 11.07%
SILICA.............. 24.00 23.72%
RED IRON OX......... 4.00 3.95%
*Copr carb........... .40 .40% (not included in
calculation)
RUTIL............... 4.00 3.95%
----------
101.20
FORMULA & ANALYSIS
------------------
*BaO........ .24 9.45%
*CaO........ .48 6.83%
*MgO........ .00 .04%
*K2O........ .19 4.40%
*Na2O....... .08 1.31%
Fe2O3...... .12 4.83%
TIO2....... .20 4.01%
AL2O3...... .39 10.06%
SiO2....... 3.91 59.08%
P2O5....... .00 .01%
*SrO........
RATIO 9.99
EXPAN 606.09
WEIGHT 396.75
My first revision replaces all the Barium Carb with Calcium Carb the
original I am sure is crazing but depending on the body you are covering -
this first one may not craze - This may even be a durable glaze but you can
test it easily - leave a variety of cut fruit on it for 24 hours (not in
the fridge) and see if the colour changes. Just to say in step I did not
bring the recipe total to % and add on the colours.
You will notice - because my totals are less than yours - that the colors
are subsequenly a little higher - I am guessing that will not make a
noticable difference - tell us about that when you get the results -
please.
RR's revision #1 of DUNHAM ^10
-----------------
CUSTER SPAR......... 40.00 41.75%
WHITING............. 17.00 17.75%
EPK................. 6.40 6.68%
SILICA.............. 24.00 25.05%
RED IRON OX......... 4.00 4.18%
*Copr carb........... .40 .42% (not included in
calculation)
RUTIL............... 4.00 4.18%
----------
95.80
FORMULA & ANALYSIS
------------------
*CaO........ .73 10.94%
*MgO........ .01 .06%
*K2O........ .18 4.67%
*Na2O....... .08 1.39%
Fe2O3...... .12 5.14%
TIO2....... .20 4.26%
AL2O3...... .39 10.69%
SiO2....... 3.90 62.83%
P2O5....... .00 .01%
RATIO 9.99 (original is 9.99)
EXPAN 563.95 (original is 606.09)
WEIGHT 372.38
This one I replaced the Barium carb. with Strontium carb. The expansion is
up a bit compared to my first I am tempted to make a wager that the
combination of the two #1+#2) will be the best glaze - I am counting on you
to let us know what happened - and when you do repost all the recipes so we
can all be enlightened.
RR's revision #2 of DUNHAM ^10
-----------------
CUSTER SPAR......... 40.00 40.61%
WHITING............. 11.20 11.37%
EPK................. 6.40 6.50%
STRONT CARB......... 8.50 8.63%
SILICA.............. 24.00 24.37%
RED IRON OX......... 4.00 4.06%
*Copr carb........... .40 .41% (not included in
calculation)
RUTIL............... 4.00 4.06%
----------
98.50
FORMULA & ANALYSIS
------------------
*CaO........ .48 7.04%
*MgO........ .00 .04%
*K2O........ .18 4.53%
*Na2O....... .08 1.35%
Fe2O3...... .12 4.97%
TIO2....... .20 4.13%
AL2O3...... .39 10.36%
SiO2....... 3.89 60.90%
P2O5....... .00 .01%
*SrO........ .25 6.66%
RATIO 9.99
EXPAN 578.33
WEIGHT 383.70
>Here is a recipe... that is used at an art center for student work.....
>
>i would like to figure out how to make it with out the barium....
>(for one reason, it is the only glaze with barium and the supply is running
>low)
>plus all health stuff...... many good blessings go to those that help....
>
>DUNHAM ^10
>Blue/rutile blue .. glossy
>Custer fieldspar.....40
>whiting........11.2
>EPK......6.4
>"Barium".....11.2
>Silica....24
>RIO.....4
>Copper Carb......0.4
>Rutile.......4
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
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