Malone & Dean McRaine on wed 18 feb 98
Aloha all;
I think I've solved my problem at last. It's the water here at our new home.
It seems to flux the glaze very slightly but more importantly it changed the
viscosity requirements a lot. I use an 18 fl. oz. shampoo bottle as a
standard. The viscosity that gave me optimum results at my old house was 820
grams per bottle. A variance of 20 grams either way would be very
detrimental. In my recent tests I thinned the glaze progressively. At 770
the color started to appear and at 750 it looked pretty good. For this
glaze, this is a HUGE modification. I can hardly believe it. The water dept.
said that there was slightly higher ph in this water 8.0 vs. 7.2. I don't
know if this could have such an effect. Anyone have any thoughts?
Apparently my materials were all fine. All the different materials I got
from various sources gave the same results including mine and Laguna's. I
did get slightly better color from tests made with water from my old
neighborhood. I'm going to get a complete analysis of the water in both
old and new locations. I'm tremendously relieved to figure this out at last
even though I still don't understand what happened. Thanks for all the help.
For reminders the glaze I'm working with is:
Vermillion Brick Red ^9-10 Ox.
50 Cornwall Stone
25 Whiting
25 EPK
8 Red Iron Oxide
Blessings
Dean
Gavin Stairs on thu 19 feb 98
At 09:31 AM 18/02/98 EST, Dean wrote:
>... slightly higher ph in this water 8.0 vs. 7.2. I don't
>know if this could have such an effect. ...
pH has a central effect on sols and gels - that is, on slips and glaze
slurry viscosities. It sounds like you've found your culprit. If you want
to get back to your old operating point, try adding vinegar to the slurry.
Quite a lot, I suspect. pH 8 is quite high. Just keep adding until your
shampoo bottle tells you you've arrived.
Gavin
=================================
Gavin Stairs
Toronto, Ontario, Canada
Bob Wicks on thu 19 feb 98
Malone & Dean McRaine:
The ph of water makes a big difference when youi mix glazes. I use either
distilled water of simply just rain water. I often place a screened bucket
under the rain spout. That at least gives you a constant for consistent
results.
Bobwicks@aol.com
Suzanne Storer on sat 21 feb 98
Bob,
What qualities can the ph affect in a glaze? The consistency or color of
colorants or everything?
Suzanne
----------------------------Original message----------------------------
Malone & Dean McRaine:
The ph of water makes a big difference when youi mix glazes. I use either
distilled water of simply just rain water. I often place a screened bucket
under the rain spout. That at least gives you a constant for consistent
results.
Bobwicks@aol.com
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