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tweaks to flt blue (no gb version)

updated wed 9 may 01

 

Autumn Downey on tue 8 may 01


As our GB runs out, I have been trying floating blue recipes that have be=
en
posted on clayart, (Ron Roy's and Alisa's). Both have the same basic
ingredients in different proportions and the results were not too
dissimilar from each other. Both resembled like old flt blue in it's
greenish phase. (we fire at cone 5)

I finally mixed a larger batch of Ron Roy's, (recipe follows) with a coup=
le
of slight changes. Eliminated bentonite (hope I don't regret this) and
boosted EPK to 22. After first test, I added 1% talc which blued the
glaze noticeably.

(I think addition of 1-3% titanium dioxide would boost the mottling and
whiteness, as 3% really made a difference in another related test.
However, that test seemed to have a more mottled than floating quality to
it so this would be a matter of preference. Could head off in the
direction of that Blue mountain pottery, I suspect!)

Appreciate everyone's sharing of glaze tests very much and have many stor=
ed
away for that rainy day.

Autumn Downey

GB-free Floating blue (Ron Roy version)
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Neph Syn............ 30.00 27.52%
Flint............... 14.00 12.84%
EPK................. 20.00 18.35%
FRIT 3134........... 36.00 33.03%
Red Iron Oxide...... 2.00 1.83%
Cobalt Oxide........ 1.00 0.92%
Rutile.............. 4.00 3.67%
Bentonite........... 2.00 1.83%
=3D=3D=3D=3D=3D=3D=3D=3D
109.00

CoO 0.04* 0.95%
CaO 0.50* 7.46%
MgO 0.01* 0.07%
K2O 0.06* 1.49%
Na2O 0.39* 6.55%
TiO2 0.18 3.81%
ZrO2 0.00 0.03%
Al2O3 0.52 14.26%
B2O3 0.42 7.88%
P2O5 0.00 0.05%
SiO2 3.44 55.35%
Fe2O3 0.05 2.09%

Cost/kg 4.36