Mary Ella Yamashita on wed 27 dec 00
To those interested in the rosenrot glaze, here are the results I got with
a variation I did using Gary Wang's Interglaze site to do some
substitutions (I dropped the strontium, since I don't have any; I also
exchanged custer feldspar and soda ash for the nepheline syenite and
wollastonite for the whiting. I made these substitutions because I didn't
have the materials specified in the original recipe). If I did all of this
correctly, it is largely due to what I have learned on clayart (thanks,
glaze gurus!). If I erred, I would be interested in any comments.
The glaze was poured over a small cup made from Standard 225 clay, which is
a buff stoneware with some iron in it.
I fired on slow (about 13 hours) in my Skutt 1027, 3" brick, with a five
minute hold. The glaze is a shiny, opaque grey with tiny red speckles
(there are more red speckles where the glaze is thicker). It has
interesting visual texture, although I'm not sure that I'm inclined to use
a grey glaze.
My version, with the analysis, follows, and I included the recipe from the
original post at the bottom, with the Interglaze analysis for it as well.
Glaze Name: rosenrot variation
Cone: 6
Recipe:
Ferro Frit 3134 15.00
Custer Feldspar 8.00
Sodium Carbonate ( Soda Ash ) 4.00
Flint ( Quartz Silica ) 31.00
Wollastonite 21.00
Epk Kaolin 21.00
Tin Oxide 5.00
Chromium Oxide ( Chromic Chrome ) 0.35
Notes:
substitutes wollastonite, custer feldspar, and soda ash; colorants
included in analysis
Unity Molecular Formula:
0.031 K2O 0.311 Al2O3 3.482 SiO2
0.219 Na2O 0.163 B2O3 0.003 TiO2
0.721 CaO 0.008 Cr2O3 0.109 SnO2
0.028 MgO 0.004 Fe2O3
0.000 MnO
Percentage Analysis:
60.56 % SiO2
0.07 % TiO2
4.75 % SnO2
9.17 % Al2O3
3.29 % B2O3
0.33 % Cr2O3
0.16 % Fe2O3
0.85 % K2O
3.94 % Na2O
11.72 % CaO
0.33 % MgO
0.00 % MnO
ORIGINAL RECIPE:
>From: will edwards
> Subject: William's Rosenrot Red ^6 ox
>>Anyone willing to use this as a test glaze please let me know your results .
> My private addy or the Clayarts post will be fine.
>
> William's Rosenrot Red ^6 Oxidation
>
From: will edwards
Subject: William's Rosenrot Red ^6 ox
InterGlaze Analysis
Cone: 6
Recipe:
Ferro Frit 3134 15.00
Nepheline Syenite 15.00
Flint ( Quartz Silica ) 37.00
Whiting ( Calcium Carbonate ) 16.00
Epk Kaolin 15.00
Strontium Carbonate 2.00
Tin Oxide 5.00
Chromium Oxide ( Chromic Chrome ) 0.35
Notes:
william edward's recipe from clayart, colorants included in analysis
Unity Molecular Formula:
0.028 K2O 0.313 Al2O3 3.483 SiO2
0.169 Na2O 0.173 B2O3 0.002 TiO2
0.752 CaO 0.008 Cr2O3 0.116 SnO2
0.003 MgO 0.002 Fe2O3
0.047 SrO
Percentage Analysis:
57.03 % SiO2
0.05 % TiO2
4.75 % SnO2
8.69 % Al2O3
3.29 % B2O3
0.33 % Cr2O3
0.08 % Fe2O3
0.71 % K2O
2.86 % Na2O
11.50 % CaO
0.04 % MgO
1.33 % SrO>
Ron Roy on mon 1 jan 01
Hi Mary,
I did the calculation and found significant differences - this may be due
to differences in the analysis between what you used and what I use. Here
is the results I came up with - ratio and calculated expansion are almost
the same between the original and my revision. I would be interested in you
testing this and seeing if it is different from your version.
Keep in mind - the red in a chrome time glazes will develope better if
cooling is slowed down - I'm not sure about when to slow down but will
guess below cone 04.
Do one test in your regular firing and another with slower cooling.
Red can be increased by increasing the chrome I think - look this up in the
Hamer book.
RR
Original Rosenrot from Willaiam.
-----------------
F3134............... 15.00
NEPH SY............. 15.00
SILICA.............. 37.00
WHITING............. 16.00
STRONT CARB......... 2.00
EPK................. 15.00
TIN................. 5.00
*chrome ox...... .35
----------
105.35
FORMULA & ANALYSIS
------------------
*CaO........ .75 ----12.58%
*MgO........ .01 ---- .08%
*K2O........ .03 ---- .79%
*Na2O....... .17 ---- 3.18%
Fe2O3...... .00 ---- .17%
TIO2....... .00 ---- .05%
B2O3....... .17 ---- 3.65%
AL2O3...... .31 ---- 9.64%
SiO2....... 3.50 ---- 63.10%
P2O5....... .00 ---- .02%
SnO2....... .12 ---- 5.26%
*SrO........ .05 ---- 1.48%
RATIO 11.12
EXPAN 431.35
WEIGHT 333.15
RR revised rosenrot red
-----------------
F3134............... 16.00
CUSTER SPAR......... 8.00
SODA ASH............ 2.00
SILICA.............. 29.00
WOLAST.............. 24.00
EPK................. 21.00
Tin .................... 5.00
Chrome oxide ....... 0.35 ----------
Total ..................105.35
FORMULA & ANALYSIS
------------------
*CaO........ .77 ---- 14.03%
MnO2....... .00 ---- .01%
*MgO........ .03 ---- .40%
*K2O........ .03 ---- .93%
*Na2O....... .16 ---- 3.28%
Fe2O3...... .00 ---- .19%
TIO2....... .00 ---- .07%
B2O3....... .17 ---- 3.87%
AL2O3...... .31 ---- 10.16%
SiO2....... 3.46 ---- 67.04%
P2O5....... .00 ---- .03%
SnO2....... .11 ---- 4.97
RATIO 11.22
EXPAN 428.53
WEIGHT 309.83
>To those interested in the rosenrot glaze, here are the results I got with
>a variation I did using Gary Wang's Interglaze site to do some
>substitutions (I dropped the strontium, since I don't have any; I also
>exchanged custer feldspar and soda ash for the nepheline syenite and
>wollastonite for the whiting. I made these substitutions because I didn't
>have the materials specified in the original recipe). If I did all of this
>correctly, it is largely due to what I have learned on clayart (thanks,
>glaze gurus!). If I erred, I would be interested in any comments.
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
Mary Ella Yamashita on wed 3 jan 01
Ron Roy,
Thank you for working through this. I hadn't realized there could be
significant variation between the analysis of different calculation
programs. I will test your formula and report back (it will be a few
months before I get two glaze firings done, but I will follow up).
I am curious about the strontium in the original recipe? Does it
contribute to color at all, or is it just there for fluxing?
Happy NEw Year!
Mary Ella
>From: Ron Roy
> Subject: Re: ^6 rosenrot variation test (long)
> Content-Type: text/plain; charset="us-ascii"
>
> Hi Mary,
>
> I did the calculation and found significant differences - this may be due
> to differences in the analysis between what you used and what I use. Here
> is the results I came up with - ratio and calculated expansion are almost
> the same between the original and my revision. I would be interested in you
> testing this and seeing if it is different from your version.
>
> Keep in mind - the red in a chrome time glazes will develope better if
> cooling is slowed down - I'm not sure about when to slow down but will
> guess below cone 04.
>
> Do one test in your regular firing and another with slower cooling.
>
> Red can be increased by increasing the chrome I think - look this up in the
> Hamer book.
>
> RR
>
> Original Rosenrot from Willaiam.
> -----------------
> F3134............... 15.00
> NEPH SY............. 15.00
> SILICA.............. 37.00
> WHITING............. 16.00
> STRONT CARB......... 2.00
> EPK................. 15.00
> TIN................. 5.00
> *chrome ox...... .35
> ----------
> 105.35
> FORMULA & ANALYSIS
> ------------------
> *CaO........ .75 ----12.58%
> *MgO........ .01 ---- .08%
> *K2O........ .03 ---- .79%
> *Na2O....... .17 ---- 3.18%
> Fe2O3...... .00 ---- .17%
> TIO2....... .00 ---- .05%
> B2O3....... .17 ---- 3.65%
> AL2O3...... .31 ---- 9.64%
> SiO2....... 3.50 ---- 63.10%
> P2O5....... .00 ---- .02%
> SnO2....... .12 ---- 5.26%
> *SrO........ .05 ---- 1.48%
>
> RATIO 11.12
> EXPAN 431.35
> WEIGHT 333.15
>
>
>
> RR revised rosenrot red
> -----------------
> F3134............... 16.00
> CUSTER SPAR......... 8.00
> SODA ASH............ 2.00
> SILICA.............. 29.00
> WOLAST.............. 24.00
> EPK................. 21.00
> Tin .................... 5.00
> Chrome oxide ....... 0.35 ----------
> Total ..................105.35
> FORMULA & ANALYSIS
> ------------------
> *CaO........ .77 ---- 14.03%
> MnO2....... .00 ---- .01%
> *MgO........ .03 ---- .40%
> *K2O........ .03 ---- .93%
> *Na2O....... .16 ---- 3.28%
> Fe2O3...... .00 ---- .19%
> TIO2....... .00 ---- .07%
> B2O3....... .17 ---- 3.87%
> AL2O3...... .31 ---- 10.16%
> SiO2....... 3.46 ---- 67.04%
> P2O5....... .00 ---- .03%
> SnO2....... .11 ---- 4.97
>
>
> RATIO 11.22
> EXPAN 428.53
> WEIGHT 309.83
>
>
>
Ron Roy on sat 6 jan 01
Hi Mary,
Happy new year to you too.
Strontium is a mid range flux - similar to Barium and Calcium - it is oflen
used to replace Barium and when it's used that way lowers expansion because
you need less if it. When anpther flux is added to a glaze - even in small
quantities you get some extra melting, more balance and - in the case of
Strotium added durability. If over done - as with other fluxes - the
reverse can be true.
My attitude is - as many as possible when consistant with surface and
colour. Complex glazes are just more reliable in the end because you are
not depending on large amounts of any one material and you avoid problems
when materials vary.
The reverse is true - simple glazes are sometimes trouble becuase some
materials will veary and if they are in large amounts they will affect the
glaze.
RR
>Ron Roy,
>Thank you for working through this. I hadn't realized there could be
>significant variation between the analysis of different calculation
>programs. I will test your formula and report back (it will be a few
>months before I get two glaze firings done, but I will follow up).
>
>I am curious about the strontium in the original recipe? Does it
>contribute to color at all, or is it just there for fluxing?
>Happy NEw Year!
>Mary Ella
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
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