Cindy in SD on fri 4 feb 05
Dear Kelly,
Colorants, opacifiers and conditioners (bentonite, CMC, etc.) are always
added as a separate percentage on top of the other glaze ingredients.
Think of it like sales tax. Let's say you buy a soft drink that is
marked $1.00. This price represents 100% of all the costs of making the
drink, plus profits for everyone who handles the drink until you select
it from the case. Tax is extra. If there's a 4% sales tax in your state,
plus a 2% municipal sales tax, then that's 4 cents for the state, 2
cents for the city.
If you're making 100 grams of a dry base glaze, plus 4% rutile and 2%
cobalt oxide, that means you'll add 4 grams of rutile and 2 grams of
cobalt oxide over and above the 100 grams of base glaze ingredients
you've already put in the bowl. One could include the additives in the
base glaze recipe--it would change all the percentages slightly--but
doing it this way makes it so much easier to vary the color, opacity,
and viscosity of the glaze.
Pam Cresswell on sat 5 feb 05
Kelly. I will toss another analogy in :-)
The base recipe that adds up to 100 ( percent, grams, pounds) is your base.
If it were food, it would be a hunk of steak or tofu. Then the colorants are
the spices/herbs/flavorings.
Add lemon juice and oregano and your entree is Greek, add ginger, soy and
sherry and it is Japanese. Add tin and chrome and your glaze is mulberry
colored, or add huge handful of RIO and it is temmoku .
I just wish my glaze calc. software looked at the additives to a recipe and
included them in
the calculations. The one I have only looks at the base recipe when it
calculates fluxes and silica/alumina and so on.
Pam, meandering down several twisty clay avenues when she should be getting
ready for her first ever little gallery show.....
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