[downtoearthpotter]

I have several glaze recipes which include american ingredients i.e. "kentucky ball clay (OM 4). I have never seen this listed in our suppliers catalogues, does anyone know what I can substitute for this? I would like to do some tests. Thanks. PS I live in Australia.

[Marcia Selsor]

Kentucky Ball (OM #4, Old Mine #4) clay is a very pure ball clay without iron or coloring contaminates. It was actually imported to Paris by the Sevres Porcelain factory prior to WWI according to people in Paducah , Kentucky. You could possible substitute an Australian Ball Clay that is very pure. If the purity (whiteness) is not a big issue, you may be able to use another less pure Ball clay. Talk to your suppliers for suggestions.

Marcia

[JBaymore]

Here's a chemical analysis of OM #4:

OM #4 Ball Clay

0.17* CaO
0.32* MgO
0.35* K2O
0.16* Na2O
0.49 TiO2
8.90 Al2O3
29.89 SiO2
0.22 Fe2O3

Calculated LOI: 12.60
Si:Al: 3.36
SiB:Al: 3.36
Thermal Expansion: 5.15
Formula Weight:2844.36


best,

..................john

[Marcia Selsor]

JBaymore, on 07 February 2013 - 09:09 AM, said:

Here's a chemical analysis of OM #4:

OM #4 Ball Clay

0.17* CaO
0.32* MgO
0.35* K2O
0.16* Na2O
0.49 TiO2
8.90 Al2O3
29.89 SiO2
0.22 Fe2O3

Calculated LOI: 12.60
Si:Al: 3.36
SiB:Al: 3.36
Thermal Expansion: 5.15
Formula Weight:2844.36


best,

..................john

Looks like there are some trace elements of contaminants.
Marcia

[jo4550]

downtoearthpotter, on 07 February 2013 - 03:22 PM, said:

I have several glaze recipes which include american ingredients i.e. "kentucky ball clay (OM 4). I have never seen this listed in our suppliers catalogues, does anyone know what I can substitute for this? I would like to do some tests. Thanks. PS I live in Australia.

Of the 3 main Ball Clays available in Australia (Ball Clay FX, Ball Clay R and Clay Ceram) Ball Clay FX has a very similar Chemical analysis. The TiO2 content is fractionally more whilst the Fe2O3 is slightly less. I have successfully substituted Ball Clay FX for OM#4 in glazes tests. However which ever you choose should be tested first as analysis change depending on what part of the pit is being mined.

I have found the Glaze Program Matrix by New Zealand ceramist Lawrence Ewing to be spot on. This program has analysis of all the main materials used in Australia. It's database of materials used world wide is extensive. It is really easy to substitute Australian materials for materials used elsewhere and make the necessary adjustments. It is the best money I have spent on glaze calculation programs for my needs in Australia.

Johanna

[downtoearthpotter]

jo4550, on 08 February 2013 - 10:05 AM, said:

downtoearthpotter, on 07 February 2013 - 03:22 PM, said:

I have several glaze recipes which include american ingredients i.e. "kentucky ball clay (OM 4). I have never seen this listed in our suppliers catalogues, does anyone know what I can substitute for this? I would like to do some tests. Thanks. PS I live in Australia.

Of the 3 main Ball Clays available in Australia (Ball Clay FX, Ball Clay R and Clay Ceram) Ball Clay FX has a very similar Chemical analysis. The TiO2 content is fractionally more whilst the Fe2O3 is slightly less. I have successfully substituted Ball Clay FX for OM#4 in glazes tests. However which ever you choose should be tested first as analysis change depending on what part of the pit is being mined.

I have found the Glaze Program Matrix by New Zealand ceramist Lawrence Ewing to be spot on. This program has analysis of all the main materials used in Australia. It's database of materials used world wide is extensive. It is really easy to substitute Australian materials for materials used elsewhere and make the necessary adjustments. It is the best money I have spent on glaze calculation programs for my needs in Australia.

Johanna

[downtoearthpotter]

Thank you so much for your reply. I will use this ball clay.

[downtoearthpotter]

Marcia Selsor, on 07 February 2013 - 10:44 PM, said:

Kentucky Ball (OM #4, Old Mine #4) clay is a very pure ball clay without iron or coloring contaminates. It was actually imported to Paris by the Sevres Porcelain factory prior to WWI according to people in Paducah , Kentucky. You could possible substitute an Australian Ball Clay that is very pure. If the purity (whiteness) is not a big issue, you may be able to use another less pure Ball clay. Talk to your suppliers for suggestions.

Marcia

Thank you for your suggestions.