GUMC
A cellulose gum rather than a plant gum, and it dissolves in water · Thickens the slurry and binds the dried layer to the bisque · Less than a part in a hundred for dipping, a few times that for brushing · Mixed into water it has no dependable shelf life; the dry powder keeps far longer
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Gum CMC is a cellulose gum that thickens a glaze and binds the dried layer to the pot. It is what makes a glaze brushable and lets a second coat go on without lifting the first.
Gum CMC is not a plant gum but cellulose treated to dissolve in water, as a sodium salt. In a bucket it thickens the water itself, which slows settling; on the pot it dries to a film that holds the layer onto the bisque. A glaze carrying it goes on thicker, brushes smoothly, and takes a second coat without lifting the first. Dipping glazes commonly take less than a part in a hundred, brushing glazes a few times that. Mixed into water it has no dependable shelf life: bacteria break the chains down, and the thickening does not come back. Some go off in days and others last months, which is why it is commonly mixed in small batches.
