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converting glaze recipe from cone 8 to cone 6

updated fri 14 oct 05

 

Laura Burch on mon 10 oct 05


Q: This recipe fires beautifully at cone 8; can anyone help me convert
the recipe for cone 6?

MSA MATT cone 9 for oxidation

Soda Spar 42
Ball Clay 4
Dolomite 8
Flint 20
Gerstley Borate 12
Talc 14
Superpax 12


Thanks!

Laura Burch
Laura Burch Pottery
laura@lauraburchpottery.com
607-275-0997

John Post on tue 11 oct 05


Hi Laura,
I looked at the unity numbers for this glaze and it falls into the
ballpark for a cone 6 glaze already.
Have you tried firing it at cone 6 without making any changes to it?
You might just find that it works as is.
If you want to try getting a little more melt in it, you could just try
adding a bit of frit 3134 of other frit in small increments of say 2 to 5%.

Cheers,
John Post
Sterling Heights, Michigan

Laura Burch wrote:

>Q: This recipe fires beautifully at cone 8; can anyone help me convert
>the recipe for cone 6?
>
>MSA MATT cone 9 for oxidation
>
>Soda Spar 42
>Ball Clay 4
>Dolomite 8
>Flint 20
>Gerstley Borate 12
>Talc 14
>Superpax 12
>
>
>Thanks!
>
>

Ron Roy on tue 11 oct 05


HI Laura,

This should do it but do a 1000 gram batch first to be sure - the only
difference is more Boron - and I subbed in 3134 for the GB - expansion is
about the same. Let me know if it needs more melt and be sure to include
the recipe as I don't keep them.

I can do it with GB but I just don't think it's a good idea because of
supply problems.

F4 Spar - 32.0
Dolomite - 2.0
Frit 3134 - 20.0
Talc - 21.0
OM #4 - 13.0 (Ball clay)
Silica - 12.0
Total - 100.0
Super pax - 12.0

RR


>Q: This recipe fires beautifully at cone 8; can anyone help me convert
>the recipe for cone 6?
>
>MSA MATT cone 9 for oxidation
>
>Soda Spar 42
>Ball Clay 4
>Dolomite 8
>Flint 20
>Gerstley Borate 12
>Talc 14
>Superpax 12
>
>
>Thanks!
>
>Laura Burch
>Laura Burch Pottery
>laura@lauraburchpottery.com
>607-275-0997
>
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Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513

Ron Roy on wed 12 oct 05


Hi John & Laura,

Yes - that was my first impression but there is a lot of MgO present which
makes for a stiff glaze - which is why I thought it necessary to add more
boron - I'm pretty sure the original will not smooth out properly at cone 6
- we shall see.

I must say - it is wonderful to see some of you - like John and Daniel -
getting on to glaze calculation. It's a great advantage to all potters to
have them looking over our shoulders.

RR

>Hi Laura,
>I looked at the unity numbers for this glaze and it falls into the
>ballpark for a cone 6 glaze already.
>Have you tried firing it at cone 6 without making any changes to it?
>You might just find that it works as is.
>If you want to try getting a little more melt in it, you could just try
>adding a bit of frit 3134 of other frit in small increments of say 2 to 5%.
>
>Cheers,
>John Post
>Sterling Heights, Michigan
>
>Laura Burch wrote:
>
>>Q: This recipe fires beautifully at cone 8; can anyone help me convert
>>the recipe for cone 6?
>>
>>MSA MATT cone 9 for oxidation
>>
>>Soda Spar 42
>>Ball Clay 4
>>Dolomite 8
>>Flint 20
>>Gerstley Borate 12
>>Talc 14
>>Superpax 12

Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513