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substituting frits for gerstley borate - it's not all that

updated wed 26 jan 00

 

Ron Roy on tue 25 jan 00

Hi Tim,

It's not that simple - the different materials I used all bring with them
different amounts of other oxides and the glaze has to be balanced by
adding or subtracting other materials.

I have thought about trying to make some general staements about how to do
this but can't see how to do it just yet.

An example: Fusion frit 309 (expensive) is the closest to Gers Borate. It
has some MgO but not enough and some talc or dolomite needs to be added to
get enough to duplicate the amount in the GB. - how much depends on the
amount of GB in the glaze.

In short - for the moment anyway - each glaze will have to be done individualy.

RR


>----------------- Message requiring your approval (65 lines) ------------------
>Hey Ron: would you mind posting the percentages of each material you subbed
>for GB?
>--
>Tim Lynch
>The Clay Man
>1117 Tedford St SE
>East Wenatchee, WA 98802-5254
>509-884-8303
>lynch.t@mail1.wsd.wednet.edu
>
>----------
>> ----------------------------Original message----------------------------
>> I just got 5 glazes out of my kiln - one with GB and the other 4 without -
>> all the same glaze - you can't tell the difference.
>>
>> I used Cadycal, Frit 3134, 3124 and Fusion frit 309 in different
>> combinations. I'll have them with me at Cermatech.
>>
>> I feel confident now I can duplicate any glaze with GB and solve the
>> problems in the bucket at the same time.
>>
>> I also feel I can make the glazes "unreliable" as well by introducing other
>> materials - which I don't think many will take me up on - especially if
>> they are trying to make a living selling pots.
>>
>> A word of cauction about stocking up on GB - the latest analysis I have is
>> quite different from ealier versions - I still think it best to have no
>> more than 10% GB in glazes.
>>
>> There is another problem in all this - Hamill & Gillespie no longer puts
>> batch numbers on their bags - the question now is - which analysis is the
>> right one for the material you have?
>>
>> There really is no need to panic about the lack of GB - as someone else
>> pointed out - this will be a blessing in the long run.
>>
>> RR

Ron Roy
93 Pegasus Trail
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