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Ball Clay, Quartz And China Clay Equivalents In The Us For Gold Glaze

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Hi all,

 

I want to try a formula for a ^5  gold glaze (it says 1230-1260 C, I suppose that's still ^5 ?) called "Gold Pigment" out of an old Ceramic Review issue, and I'm not sure what are the US equivalents to the UK materials the formula calls for. The entire formula is:

 

Manganese dioxide     43

Copper oxide     5

Cobalt oxide      5

Red clay     57

Ball clay      4

Quartz      5

 

So what red clay? Redart?

Which of all the different ball clays we have in the US??

If I use Silica 325 is it the same as the quartz this formula has? Is flint also the same as quartz?

 

Also, another formula, a ^4-7 bronze, calls for china clay. Is it the same as kaolin?

 

And to continue giving away that I know NOTHING of glaze formulation: how come this formula when added up is over 100?

 

Thank you in advance for any wisdom you can send this way. :)

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Silica = Quartz = Flint. Now they might not be exactly the same but only slight impurities.

Any time I see red clay I take that to mean terracotta, anything in that category of iron rich earthenware.

Ball clay again I think you can use any ball clay. I only get one option of ball clay from my suppliers in UK so not much choice there.

 

China clay = Kaolin.

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Joel is right on about the equivalents.  The reason iit doesn't add up to 100 is because it is not a glaze.

the manganese, copper and cobalt are metallic oxides as well as a good percentage of the red clay.

This will be a very metallic surface, possibly almost luster like. DO NOT USE ON A FUNCTIONAL PIECE where it comes in contact with food or liquids. Also use caution when mixing, and firing. Manganese can penetrate skin, dust and fumes are hazardous.

 

Marcia

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^^^ what everyone else said.^^^

 

I suspect that the title may be misleading. With that much manganese, it looks like it might be more of an antique bronze, heavy on the brown, than gold. Firing cycle is very important to acheive the metallic results in any of the bronze glazes I'm familiar with. I don't know the best way to go about getting the best results on this one though. Don't stress out about material substitutions too much, and red art is probably a good place to start for your red clay. That level of colourant (the first 3 ingredients on your list) is going to overpower any visual contributions that the other clays might normally contribute.

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Thanks, guys!

This formula is called "gold pigment" (it's supposed to be used as a glaze but technically speaking it's considered a pigment) and I want the most metallic gold look possible. If you have any recipes that would do this, I'm all ears!!  :)

I would love to get a successful firing schedule for it... anybody has any idea? It's for cone 5.

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