Techno Tip

Painting Glazes

Likely you have had problems getting
glazes to apply evenly when dipping ware
Many dipping glares dry too fast or too
slow, drip or curtain during draining, settle
oul quickly, crack duning drying or go on
tog thick or thin, In industry ‘lay-down’ is
considensd a big factor in the ability to fire
a piece with an even glaze layer free of
defects. On small or delicate ware it can be
very difficult to achieve good laydown.

If you have ever used commercial glazes
from Duncan or Mayeo you know that
although the idea of painting glaze onto
ware can be quite strange to potters, it
actually works very well. It is just about
Impossible to evenly paint a typical dip-
ping glaze: they dry way too fast and just
don’t How like paint. So how does Duncan
or Spectrum make a glaze ‘paintable’?
The answer is gum, Lots of gum.

CMC gum, for example is an organic so-
dium carboxymethyleellulose (like a glue}
that is normally employed te harden unfired
cerame glazes (cement the particles to-
gether) for safer handling of the ware,
Although CMC gum is pot intended as a
suspending agent, amazingly it can do
exactly that. You can actually make frited
glazes that contain almost zero clay con-
tent and suspend and harden them totally
using gum.

Avery mice side effect of the addition of
gum is that glates dry slower, In fact, you
can tune the amount of gum in the mix te
achieve the drying speed you want. It
should paint and flow nicely but dry fairly
quickly after laydown.

How much should you wse and how do you
pul gum ina glaze? Powdered gum resists
dispersion in water, thus itis difficult to
add it to an existing liquid batch. However
if gum powder is mixed with other dry
ingredients before adding them to the wa-
ler it can be done (often O.4-1.5%), A
much more effective methixl is to boil
water, add about 25-30 grams of pow-
dered gum per litre and mix vigorously
with a mechanical mixer. Normally this
mixture is added during mixing to replace
part of the water; however I have found
that for brushing, it should be used to
makeup the entire water complement.
There is room to use 40 grams per litre if
needed.

Cia

Amazingly, even though the gum solution
is quite thick and syrupy, added powder
mixes in very easily, The gum solution
seems fo wel the particle surfaces better
than water alone.

Each glaze will paint a limle differently, If
you find that a glare dines too quickly and
does not flow enough try adding a litte
more water before deciding thet the gum
CONLENT ES Loe low,

Consider some of the advantages of paint-
ing glazes:

If you make small preces you can make
small batches of glaze and even store them
in glass containers tic. large baby food
jars). Thus you can have a bot more glazes
at your disposal

You don't need to bisque fire. Glaxe paints
onto greenware just fine, you just have to
be careful when handling the ware if it is
than

You can apply very thin layers and apply
multiple layers of different types of glaze
for visual or decorative effects,

You can make specialized glazes of very
low clay content or you can use bower iron
and less plastic kaolins (as opposed to
dirtier ball clays) to make cleaner and
whiter glaze surfaces.

For more information on gum please visit
hitpolwwew.cme-silts.com home. htm.
Tony Hansen

Techno Tips are written by Tony Hansen
with the sappert of Plainsman Clays
Limited in Medicine Har, Alberta,
Greenbam Potters Supply in Surrey, and
Vancouver Island Pottery Warehouse Inc
near Nanaime are local affiliates,

Letter to Tozan Cultural Society

The Tezan Cultural Society received this
email from the mother af one ef our young
metibers. This type af letter is what we of
the ‘Tozaa’ want to accomplish for the
young students, to teach them ta lowe the
ire, learn from the more experienced pot

terscund learn the techniques af woodfiring,

Dear Tozan:
RE: August Pestival/Firing 2001

1 have just gotten off the telephone with
our daughter who was bubbling over with
the thrill and excitement of being part of
this Tozan firing. She had just come from
ithe evening ceremony of August 9 includ-
ing the Korean dancers, slip trailing of
names, and pieces to be exhibited. The
descniptions were coming so fast and furi-
oes that I barely had time to keep straight
the sequence of events that has happened
to her over the past weeks. Nothing is so
priceless as the enthusiasm of one in-
spired.

I belheve that this has been one of the very
bes experiences a young potter could pos-
sibly have had and I cannot thank the
Tozan community enough for allowing
our daughter, Samantha Carniato to have
her work fired, to have her turn feeding the
fire, and the experience to meet and be
inspired by all those involved.

You are all very gifted. I thank you for
sharing that gift with her,
Sincerely

Louise Carniate
Qualicum Beach BC Canada

Tovan: Murray at dowe