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glaze goof ~ substitutions?

updated mon 12 apr 99

 

SolvejgMa@aol.com on sun 11 apr 99

Hi folks ~

Last weekend I decided to finally mix up that big batch of Mexico Point
Green I've been wanting (5000 grams is big for me), and everything went great
until I got to the Zircopax. My recipe called for 885 grams, and I had
exactly...404 gm. Oops. Everything else was already in the bucket, the clay
store was closed, and my elderly Czech neighbor, while she might be able to
loan me a pound of poppyseed for Kulosh, certainly wouldn't have any spare
Zircopax. I checked some reference books to find a replacement and thought
titanium dioxide might do, but I didn't have enough of that either. I added
it to the mixture along with the Zircopax. Still worried I was coming up
short on something, I added a little tin to the mix. (This is how I cook,
too. It's usually edible.)

I have yet to fire this stuff, and who knows what I'll get, tho the general
glaze analysis looks pretty similar to the original recipe. What I'd really
like to know is, what are the major differences between Titanium Dioxide,
Zircopax (Plus), Superpax, and Tin? They're all opacifiers, right? I know
Tin is expensive. Titanium and the pax'es are cheaper, and they may cause
crystal growth, or so I've read. But are there any other defining
characteristics? Can any/all of them be substituted for each other, straight
across? Do they have different effects on the coloring oxides?

FYI, the resulting recipe looks like this:

Mexico Point Green, Oops ^6 -7

Custer Feldspar 1065
Gerstley borate 510
Spodumene 600
Talc 410
Whiting 380
EPK 265
Zircopax 404
Flint 915
Titanium dioxide 368
Tin oxide 30
--------
4947
add:
Bentonite 85
Copper Carb 110

(I didn't bring it back up to the original 5000 gm batch... my courage failed
me.
I'll let you know what it looks like when it comes out of the oven... :)

Thanks ~
Kat
Salem, Oregon... where yesterday we drove home from Portland in sunshine,
rain, snow, hail, high winds, "snail", more rain, more sunshine, and thought
we spotted a tornado forming over town... just another Oregon spring day.