Michael Wendt on sat 3 nov 07
A thought occurred to me as to how we
could utterly foolproof glaze mixing in almost
any setting:
1. Go to the store and buy lunch bags or
small grocery bags all the same size.
2. Write the glaze name and ingredient
name and weight on each bag.
Before beginning, the entire recipe
will have a bag (or as many as needed)
for each glaze component so that the
entire recipe can be dry weighed first
at the limits of the scale capacity.
Check the math carefully the first time.
3. Tare the scale to the bag and fill with
indicated weight. Here's the trick!
In the thread " can this glaze be saved"
I think the glaze lab at the school didn't
have accessory weights so the students
were weighing the materials in 500 g
lots and dumping them in... a very bad
practice. Filling the bags with the correct
ingredient each time eliminates counting
errors since if I need 1500 g of silica,
I will have three bags labeled:
Chun base cone 10 ( your glaze name here)
Silica 1500 g ( total wt for recipe)
bag 1 of 3 500 g ( bag number and wt)
4. Do not add anything to the water
until all the recipe is bagged and you
double check the math.
As an added precaution, to reduce
the chance of supplier mistakes
(I've seen them too!) I suggest that
schools always order products where
possible to be in their original bags so that
critical components like feldspar and silica
are real. After all one white powder is
as good as another to the minimum wage
guy they hired to repack the product.
When done, the bags are flattened and placed
in a larger bag labeled with the recipe for the
next use.
I would not add colorants or modifiers this way
but blend the main batch with water first.
Test fire a piece with the base glaze and compare
it to a previous control sample. If the new batch
is bad, toss it!
Once you are sure the glaze is right, add the
colorants and pacifiers per the recipe to
avoid wasting expensive stains and oxides.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave.
Lewiston, Id 83501
U.S.A.
208-746-3724
wendtpot@lewiston.com
http://www.wendtpottery.com
http://UniquePorcelainDesigns.com
| |
|
