Don Goodrich on wed 15 nov 06
You can use red iron oxide to tint clear glazes.
They don't need to contain lead (thank goodness).
The cone 6 honey glaze I use has 7% iron oxide.
Varying the amount will give you more or less color
on the amber-red-brown scale.
Vicki Wicker on wed 15 nov 06
In Mary Wondrausch's book on slipware, she tints her clear earthenware
glaze with iron oxide to get a transparent honey colored overglaze.
However, its a lead-based glaze and I don't want to use lead. Will iron
oxide do the same for a non-lead based clear glaze? I've got a few
different recipes I've found here on the list, frit based for the most
Ivor and Olive Lewis on thu 16 nov 06
Dear Vicki Wicker,
I have a high fired transparent cone 8 glaze which, with about 4 to 6 % =
Manganese Carbonate, that gives a good impression of Honey. This glaze =
is based on Soda felspar.
My suggestion would be to try this colorant in a glaze based on one of =
the lower melting point frits, avoiding any ingredients which might =
opacify or mat the surface. A good place to begin would be a line blend =
of white clay with one of the Frits to find a composition that would =
work well with your earthenware clay.
Russel Fouts on thu 16 nov 06
>> In Mary Wondrausch's book on slipware, she tints her clear
earthenware glaze with iron oxide to get a transparent honey colored
overglaze. However, its a lead-based glaze and I don't want to use lead.
Will iron oxide do the same for a non-lead based clear glaze? I've got a
few different recipes I've found here on the list, frit based for the
most part. <<
Good timing. I just completed some experiments with a nice non-lead
clear glaze (88% Ferro 3195, 12% Kaolin) and 1, 2, 3 and 4% Red iron oxide.
Nope! you don't get that nice amber without lead and a little calcium
(according to Tony Hansen)
I got some nice results, none of them unappealing, the lower percentages
were nicer than the higher but they weren't honey/amber colored.
Simulating a honey/amber lead glaze with a non-lead glaze was covered
quite extensively last year or the year before on this list.
You can probably find the posts in the archives. Or maybe the woman that
was conducting the experiments will chime in.
I believe she got what she wanted or near enough with a combination of
stains in the clear glaze and maybe in the underlying slip as well.
Jeanie Silver on fri 17 nov 06
There is an excellent honey-colored 03 glaze in Susan Peterson's 'Smashing
Glazes'. It calls for 7% raw umber.
Jeanie in Pa.
Russel Fouts on sat 18 nov 06
I had a look in "the Potter's Pallet" and all the low-fire, non-lead
amber glazes were alkaline.
Beautiful, with lots of crackle (lf course!) but they tended more
towards yellow than amber.
Is the glaze below, by any chance an alkaline glaze? It doesn't look
like it with the Potash Feldspar. What about the Neph-sy?
> Hi Russel,
> Since she wasn't specific about the temperature in her original post,
> I responded from my ^6 experience. The glaze I refer to is one I think
> was posted on ClayArt some time ago:
> POTASH FELDSPAR 20.00
> GERSTLEY BORATE 20.00
> NEPHELINE SYENIT 20.00
> FLINT......... 15.00
> WOLLASTONITE.. 10.00
> DOLOMITE...... 2.00
> EPK KAOLIN...... 5.00
> IRON OXIDE RED.. 7.00
> TITANIUM DIOXIDE 1.00
> Oddly, I have the name of this glaze as Weiser's Honey. But that's
> a very different cone 9 glaze. Whatever the case, It seems that one
> could flux this down to earthenware temps, but maybe I'm wrong.
> I've noticed that small amounts if iron, and iron-bearing clays like
> burnt umber, do seem to bleach out in firings. Do you think there's a
> critical level of iron above which the color is significant?
> Maybe the thing to do is to keep adding iron until consistent color
> develops. I'd expect that if one stopped short of the
> saturated-iron blood reds there may be a honey along the way.
Russel Fouts on sat 18 nov 06
>>You can use red iron oxide to tint clear glazes. They don't need to
contain lead (thank goodness). The cone 6 honey glaze I use has 7% iron
oxide. Varying the amount will give you more or less color on the
amber-red-brown scale. <<
That's good to know!
So what was my problem? Lower temp (^04)? Something about Ferro 3195? My
Linda Arbuckle on sun 19 nov 06
While this is not as delicious as a lead amber and is a bit browner,
it's in that general direction and looks good over terracotta and
terracotta with slips. It was originally contained barium, which has
been replaced w/strontium carb. If you remove the barium or strontium,
you lose the honey-ish effect.
Faux Lead Strontium Base 04- 03
frit 3134 45.1
strontium carbonate 2.5
Custer feldspar 22
alumina hydrate 2.2
Color response similar to lead green and amber. No lead. Looks good
over slips. amber: + 5-7% burnt umber
transp. grass green: + 4% copper carbonate