search  current discussion  categories  glazes - chemistry 


updated wed 10 oct 01


mel jacobson on tue 9 oct 01

here is a simple but effective test for glaze application.

save some old bisque pots and crack them up to various
palm sized pieces.

mix your glaze well and visually check for thickness.
(you don't put your hands in barium glazes....
and i teach keeping your hands out of glaze buckets.
but, it does work well....the finger test.)

then using a sweep second hand on a clock or watch
time your plunge into the glaze bucket with the test bisque.

so, for example, put it in one inch for three seconds, move
it an inch lower for three more seconds, then lower it
again an inch for three more seconds. then again.

the lowest test will be the thickest.

take a sharp knife blade and check the thickness of
each of these. the best one will be as thick as a post card.

proper, consistent glazing should be done with counting
or using a second hand. if your glaze is thick, well, you may
only have it in the bucket for 4 seconds.

in most cases, i count for a total of 10 seconds.
when i double dip.. three seconds each glaze.
then a two second top coat.

i use one cup measuring cups, taped to a dowel rod
and use it as a constant stirring tool, and of course use
it to fill insides of pots. never touch glaze with my hands.
clean as a whistle. (a strong ring foot helps.)

over the years, seeing thousands of pots, i would say that
most people glaze too thin. fear keeps them that way.
stable glazes that do not run, and a good visual cone check, even
in electric, makes for great glazes.

those rich ron roy blacks do not work when applied thin.

so much about glazing is timing and feel...but, you can test and test
your thickness in the bucket, but if you do not get it on the
pot...who cares?

A GREAT TEST is taking a tube shaped pot. put it one fourth
of the way in the bucket for three seconds, then half way for three
seconds, then three quarters, then all the way.. fire it.
you now know what your glaze will do when applied properly.
just find the thickness you like, as you will have four glazes.

when working in the japanese studio, we all could glaze
pots, all used a sweep second hand....7 seconds each.
and you could not tell who threw the pots, who trimmed
the pots, or who glazed them.
all the same.
science...what a concept.
one, two, three, four.
shut the door.
going to fly to denver tomorrow.
not taking anything.
just a toilet kit, almost empty, and a
few clothes.
will buy anything i need at kmart.
give stuff to the poor and needy when i leave.
no fear.
hell, i would ride in one of those fa18's, just
for the ride.
Minnetonka, Minnesota, U.S.A.
web site: