Jonathan Kaplan on sun 18 jan 98
With all the posts reagrding these areas over the last week or so, I
thought I'd mention how we do it here in a small production factory/plant.
We keep a rather detailed notebook using Hyperglaze and/or Insight for our
clients glazes. Not only are the formulas recorded, but are glaze
additions, specific gravities, etc.. The most important columns are the
large batch calculations that allow us to mix 30,000 grams, 50,000 grams,
100,000 grams etc. without the fear of "mis-mixing." We make a wide variety
of work for different clients and each requires a different approach to
glazing.
We have 5 gallon buckets of various glaze additives such as CMC solution,
VeeGum solution, Bentonite solutions, etc. etc. These are all aequeous
dispersions that we can readily add to a glaze. We also use small
quantities of PVA, Peptapon, Optipix, Flocs, etc., and have these in small
quart containers.
Our glazes are weighed in a standard manner. We have records of the amount
of water necessary for a full batch. We measure out about 3/4 of that
amount of water and add the dry mix and let it sit for about 30 minutes or
so to wet. We use a large Jiffy mixer and mix the entire lot. We will soon
use a high velocity air driven dispersion mixer as soon as I finish
building it. At this point we can add what ever glaze additives are
required for the particular mix. After a few more minutes of mixing, we
seive the glaze through a 40 mesh seive and then through a 60 mesh seive.
The specific gravity of the glaze is then checked, and if we need to add
additional water, we do it to bring the SG to the required number. We date
the glaze on the container, and then begin work. Sometimes we add some
Listerine to reduce offensize odor and glaze scaling on the bucket
interiors and rims.
I don't think there is any mystery to glaze mixing, just a proper
methodology. Specific gravity is very important as it will determine to a
large part, the thickness of the glaze coating, as well as bisque
temp(porosity), humidity in the shop or lack of it, and if dipping, lenght
of imersion in the solution.
We have recently been pouring and spraying alot of glaze for a particular
client. The glaze for pouring has a higher SG. The glaze for spraying has
some CMC and VeeGum in it.
Jonathan
Jonathan Kaplan http://www.sni.net/ceramicdesign/
http://www.ceramicsoftware.com/education/clay/kaplan1.htm
jonathan@csn.net
Ceramic Design Group Ltd./Production Services Voice:
970-879-9139 POB 775112
FAXmodem: same
Steamboat Springs, Colorado 80477, USA CALL before faxing
Plant Location: 30800 Moffat Avenue #13 Steamboat Springs Co 80487
(please use this address for all UPS, courier, and common carrier
shipments)
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