Elizabeth Canupp on mon 11 apr 05
Hello Clayart friends:
Three years ago I purchased 50 pounds of Gerstley Borate. At that time I
mixed 3 glazes (all utilizing the Gerstley Borate) and none of them
melted. I figured I had done something wrong but didn't have the time to
research. Yesterday I mixed 4 different raku test glazes all using this
batch of Gerstley Borate and guess what??? Right. Not one of them
melted. I have taken the temperature as high as a cone 04 firing. I even
tried the torch on each of the test tiles--nothing--just black. Anyone
ever experience this problem?
Elizabeth Canupp
jesse hull on mon 11 apr 05
Yep. Been there. I worked with Raku for the first
year and a half that I was in school. My professors
had just purchased about 200 lbs. of Gerstley. I'd
tested about 20 different glazes and got quite
proficient at producing nice flashings in the post
fire reduction. Then the bin ran out in the glaze
area and I refilled it with the barrels of the new
stuff. Couldn't get a single test to melt. I was so
pissed that it became a vendetta, so I took one to
cone 8 in an electric. The glaze had sintered itself
to the clay, but was still dry and chalky.
I know that ceramic materials vary from batch to
batch. I now buy all my frits, feldspars, and
colorants in large quantities and test first to avoid
major losses due to those pesky inconsistencies. I
heard Gerstley Borate was notorious for that... more
so than other stuff.
Sorry it had to be under these circumstances, but it's
good to meet ya... Here I thought I was the only one.
~jessehull.
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