Llewellyn Kouba on mon 17 jan 05
I am working on some majolica test tiles. I have read that CMC can be
used to make the working glaze surface less powdery for overglazes or
onglaze work. Does anyone have experience on how much CMC to add to say
5,000 gram bucket or 10,000 grams of Majolica tin glaze.? Thank you
Llewellyn Kouba
Abbey Pottery
bonnie staffel on tue 18 jan 05
Dear Llewellyn,
I use dry CMC in the amount of 1/4 of 1% of the total grams of material in
the glaze. I then thoroughly mix it in one of the dry materials before
adding to the water. If you use hot water to mix your glazes, the slaking
works faster. Otherwise, let the glaze stand overnight before sieving. In
this situation, you use much less water than you would normally. I can't
tell you how much, but I mix the glaze as thickly as I can, mix it up, then
test with my hydrometer. I then add water to read 1.7 or 17, forget
which, that is where my glaze works best. It is very runny, similar to how
deflocculated slip works. I moisten my bisque with a big sponge before
dipping. Then test with a shard timing in three increments. Check with a
pin tool to see how thick it is. when it is to your liking, then go ahead
and use it. This plan works for me and has for 30 years with the same
glaze. You will find that the ingredients do not sink readily, just need an
initial stir to make sure the water on top is integrated in the glaze.
Warm regards,
Bonnie Staffel
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
Charter Member Potters Council
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