will edwards on thu 8 mar 01
Rosenrot has always performed well for me. It is very particular and even=
while some have tried to fix it, I must say that the original formulae sh=
ould
first be your choice prior to changing out things for additional durabili=
ty.
If you want reds that work you will have to work toward limits that are o=
n the
tail end of acceptable for 6^ 0x. (For this glaze)
Firing has been done several ways. We simply use a medium fire mode on ou=
r
digital kilns now and fire to ^6.(10 mintue hold at the top). However we =
never
took any extra pains when we fired using manual kilns. (Ramping/cooling n=
ever
seemed to matter that much here.)
The AL203 is very low and the silica is about mid-point. They are several=
things to take into consideration. Do you want food-safe. Well how much i=
s
0.35% of 1% going to leach? (Lab reports only can tell you this.) We are =
still
talking about Trivalent Chromium also.
Barium is not a suitable substitute for this glaze! The glaze must be
formulated as it was presented. Ron's version didn't work for me either!
I worked for months on this glaze and it is a solid deep burgundy to a bl=
ood
dark red especially after a good grinding. Let it set for a few days and =
try
it when you mix it.
I run several calculations programs and MATRIX is the one I am using mos=
t of
the time. However I am setting some new chemical analysis right now and m=
aking
some changes in my recipes profiles. Try this one and see where it goes.
Tested on B-Mix 5-7 and on Standards #205. The B203 to the CaO is in the =
ratio
and proportion for a good Pink to red based on chromium content. Fixing a=
recipe without determining if it needs fixed is how we make so many
inconclusive decisions that mess the data up that was put out in the firs=
t
place. No potential food surface glazes should be used without additional=
testing unless they are of inert materials known for zero or near zero ha=
zards
leachates. 0.40 of 1% or less than 1/2 of 1% is pretty low for trivalent
chromium isn't it even it it leached some. Since no one has told me where=
any
toxic information is on such chromium use and carcinogen potentials for
trivalent chromium please have it tested at your own level or consider it=
decorative. It is low in AL203. Changing the formulation without using
exacting materials is no way to test a glaze and reporting back the finds=
unless it is one of enhancement. Its not an E.Z. task removing GB from a=
glaze and re-writing it to work like an old GB glaze of the past. Changin=
g any
material has similar effects unless it is a cross-over of near exacting
quanity and quality.
- in mols .6 CaO to .15 B2O3. (For chrome reds)
Let me know if you try it again. =
Glaze Name: Edward's Rosenrot (Burgundy Red) =A9 2000-2001
Cone: ^6 Ox.
Recipe:
Ferro Frit 3134 15.00
Nepheline Syenite 15.00
Flint ( Quartz Silica ) 37.00
Whiting ( Calcium Carbonate ) 21.00
Epk 10.00
Strontium Carbonate 2.00
Notes: 00.40% Chromium Oxide green + 5.00% Tin Oxide.
0.023 K2O 0.212 Al2O3 2.857 SiO2
0.145 Na2O 0.148 B2O3 0.001 TiO2
0.790 CaO 0.001 Fe2O3
0.002 MgO
0.040 SrO
=
57.74 % SiO2
0.04 % TiO2
7.27 % Al2O3* Bottom of the limits for Al203 @ ^6.
3.47 % B2O3
0.06 % Fe2O3
0.73 % K2O
3.02 % Na2O
14.90 % CaO* keep the CaO up around .70 mols, =
0.03 % MgO
1.40 % SrO
William Edwards
____________________________________________________________________
Get free email and a permanent address at http://www.netaddress.com/?N=3D=
1
| |
|
