Can I substitute these chemicals

[Marge]

Hi there, I'm busy making some glazes and confused about a few chemicals... I have Magnesium Carb and the recipe calls for Manganese Carb. I have zircopax and recipe calls for zircopax plus. I have talc and recipe calls for Texas Talc. AND is EPK same as China clay???

I'd love any, if not all, of these answered but would love ANY assistance.

Thanks a bunch!!!

Margie

[Mark C.]

The answer is yes on all your materials except the magnesium carb which is white and Manganese is usually darker and a colorant-I'm unclear on the carbonated form of that?Not sure I have seen that

so Zircopax and super pax-same thing

Texas talc=talc =only everything in Texas is bigger right

EPK=China clay

[Magnolia Mud Research]

Margie;

Magnesium Carb and Manganese Carb different materials. Magnesium is element #12 in the periodic table; Manganese is element #25. They are NOT subs for one another. 

Magnesium carb brings magnesium oxide to the glaze which generally makes the glaze matte and generally does not significantly effect glaze color.

Manganese carb brings manganese oxides to the glaze which makes the glaze more runny and produces dark colors - black and purple when I have used it. 
 ....
Zircopax and Zircopax plus are nearly the same material and produce the same effects.  I would sub one for the other and not look back. 

...

Talc is talc. Use your talc for Texas talc. 

...

EPK and China clay are interchangeable. 

LT
 

[Min]

Zircopax Plus, aka Superpax, is a finer particle size than Zircopax so in theory the former will give a bit more opacification. If the zircopax  doesn't get your glaze quite white enough just add another percent or two and it should do it.