Gerstley Borate
 

My supply of G.B. is almost exhasted and was quite relieved when I read
recently that it was becoming available again, however my local supplier in
Hamilton, New Zealand, is not aware of any news like that. He also said
that he had not had good comments from customers about the use of
substitutes and he is not stocking any substitutes at the moment.
I use it in some C6 and raku glazes. Two questions...........
Is anyone able to confirm that G.B. is available again?
What is the most successful substitute that you have found?
Thanks in advance, Hugh.

"Hugh Prosser" wrote in message
...
My supply of G.B. is almost exhasted and was quite relieved when I read
recently that it was becoming available again, however my local supplier
in
Hamilton, New Zealand, is not aware of any news like that. He also said
that he had not had good comments from customers about the use of
substitutes and he is not stocking any substitutes at the moment.
I use it in some C6 and raku glazes. Two questions...........
Is anyone able to confirm that G.B. is available again?
What is the most successful substitute that you have found?
Thanks in advance, Hugh.



Not up to date but you might like to try Wellington Potters Supplies
or phone 04 939 1211. Brian is usually at least up
to date and I know that he does recommend or offer substitutes.

Dear Hugh and friends:
I have had good success with cone 9 to 12 glazes using Laguna Borate
and Akiko Borate. Substituted 1:1. There is some additional loss on
ignition (LOI) than Gersteley Borate. The thing is, I had an instructor
decades ago tell me that Gersteley Borate was a substitute for
Colemanite and that at the end of the vein of Colmanite the amount of
LOI varied. He said that Gersteley Borate was not that great either in
terms of LOI. He said this would account for variations in batches of
glaze. I used Gersteley Borate in Chun series glazes and copper reds and
three different crackle clear glazes. So this is a very important
problem to me. Turkish Colemanite is available in Europe. Its the
original material that was used to supply Boron in the glaze. It
contains more Calcium than Gersteley Borate. The formula for my Chun has
an addition of 100 grams of Whitting. This would support the theory that
the original Chun Series was based on Colemanite and someone in the
1940's translated the glaze to use Gersteley Borate because Colemanite
could not be supplied in the USA. Gersteley Borate was available in USA.
Potters' like Michael Cardue, Bernard Leach, Daniel Rhodes delt with
problems like this and past their findings along. Now as materials run
out or mines are closed due to environmental regulation, we are probably
going to have to find new sources for Feldspars and other materials. As
much as replacement formulation is based on glaze calculation methods,
the real work of testing, testing and testing will have to take place.
Some things will translate right over, as in the case of Laguna Borate.
Some things will have to be worked out.
Good luck
Russ Andavall
www.firegodarts.com

Hugh Prosser wrote:

My supply of G.B. is almost exhasted and was quite relieved when I read
recently that it was becoming available again, however my local supplier in
Hamilton, New Zealand, is not aware of any news like that. He also said
that he had not had good comments from customers about the use of
substitutes and he is not stocking any substitutes at the moment.
I use it in some C6 and raku glazes. Two questions...........
Is anyone able to confirm that G.B. is available again?
What is the most successful substitute that you have found?
Thanks in advance, Hugh.