[Clayart] white glaze (^6, Ox)

[ronroy at ca.inter.net]

This is true but - if anyone adds anything toxic to it that toxic  
material will leach out in use.
Nothing wrong with using your imagination to extrapolate possible problems!

RR


Quoting Edouard Bastarache <edouardb at colba.net>:

> There is nothing toxic in this base
>
> Plejkore,
>
> Edouard Bastarache
> Spertesperantisto
>
> My Books :
> http://bookslivreslibroj.blogspot.ca/
> http://foolingaroundwith.blogspot.ca/
> http://newbookclays.blogspot.ca/
> http://quebecstonewareglazes.blogspot.ca/
> http://quebecstonewareglazesii.blogspot.ca/
>
>
>
>
>
>
>
>
>
>
> ----- Original Message ----- From: <ronroy at ca.inter.net>
> To: "Clayart international pottery discussion forum"  
> <clayart at lists.clayartworld.com>; "Madeleine Hall-Arber"  
> <arber at mit.edu>
> Cc: <clayart at lists.clayartworld.com>
> Sent: Saturday, April 07, 2018 1:23 PM
> Subject: Re: [Clayart] white glaze (^6, Ox)
>
>
>>
>> Hi Madeleine,
>>
>> There was not much difference when you subbed in Min spar for the  
>> F4 - certainly not enough to make it matte. Did those kiln loads  
>> cool  slower than usual?
>>
>> This glaze is not stable by the way - short of both alumina and   
>> silica. I would not recommend it as a liner glaze.
>>
>> You should mix up a mall batch to see if you made a mistake.
>>
>> This one is a bit closer to the original.
>>
>> 19.50  DOLOMITE
>> 13.00  GERSTLEY BORATE (Laguna June 2011)
>> 26.00  SILICA
>> 41.00  FELDSPAR MINSPAR 200 (soda)
>> 13.00  ZINC Oxide
>> Total = 112.5
>>
>>
>> 0.33* CaO
>> 0.22* MgO
>> 0.04* K2O
>> 0.10* Na2O
>> 0.31* ZnO
>> 0.00  Fe2O3
>> 0.00  TiO2
>> 0.10  B2O3
>> 0.15  Al2O3
>> 1.85  SiO2
>> Si:Al:  12.12
>> SiB:Al:  12.76
>> Thermal Expansion: 484.50
>> Formula Weight: 196.24
>>
>> RR
>>
>> Quoting Madeleine Hall-Arber <arber at mit.edu>:
>>
>>>
>>> I have used a glossy white glaze that runs a bit when thick, but  
>>> has  a beautiful effect when dripped a bit over (or under) other  
>>> glazes. Suddenly, it came out with a matt finish.  The first time,  
>>> I thought maybe I hadn't quite reached ^6, but the second firing  
>>> was clearly  ^6. It is possible, of course, that I made a mistake  
>>> in mixing, but  was wondering if anyone knows if the switch from  
>>> Kona F4 to Minspar  could be responsible? (I think that is the  
>>> only change in chemicals  since the last time I mixed this glaze  
>>> with the possible exception  of a new bag of silica.)
>>>
>>> White, glossy, ^6
>>> Dolomite 19.5
>>> Gerstley Borate 13
>>> Silica 28.6
>>> Feldspar Kona F4 (sub minispar) 39
>>> Zinc Oxide 13
>>>
>>> Thanks,
>>> Madeleine
>>> P.s. I think I found the "Purple Bright" I asked about a few days   
>>> ago listed as "Bright Purple" in Britt's book!
>>> -------------- next part --------------
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>>
>>
>>
>> Ron Roy
>> ronroy at ca.inter.net
>> Web page ronroy.net
>>
>>
>>
>
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Ron Roy
ronroy at ca.inter.net
Web page ronroy.net