CMC Veegum question

[Roberta12]

I know that CMC and/or veegum is used in glazes for brushablity (real word?) however I found a recipe that calls for both of those.  Since I do not have either substance, can I sub the bentonite that I have?   

Neph sye                      37.50

Dolomite                    27.50

spodumene                25.00

tin ox                                7.50

whiting                             2.50

CMC                                  1.50

Veegum                            1.50

Roberta

[liambesaw]

You can sub bentonite for the veegumT, it's not as powerful though so you'll need more like 3-5 bentonite.  Cmc is the brushing medium, not sure if there's a sub for that.

The veegumT is there because the glaze has zero clay and will turn to a rock at the bottom

 

[Roberta12]

17 minutes ago, liambesaw said:

You can sub bentonite for the veegumT, it's not as powerful though so you'll need more like 3-5 bentonite.  Cmc is the brushing medium, not sure if there's a sub for that.

The veegumT is there because the glaze has zero clay and will turn to a rock at the bottom

 

Thank you!  I should have noticed the "no clay" 

[neilestrick]

Vee-Gum T and CMC are often used together for brushing glazes. When I worked at A.R.T. clay that was how we mixed our brushing glazes. VGT is expensive, though. CMC is cheap, and works very well by itself for brushing formulas. CMC can also keep it in suspension, although adding 2-3% bentonite will help a lot, too. I wouldn't use the CMC for a dipping glaze. If you use CMC, also add about 1/4 of 1% copper carbonate as a preservative, because bacteria will eat away the CMC very quickly.