[Clayart] Deflocculent

[glasshole09 via Clayart]

In raw clay glaze, Cone 6-8, call it Bristol type, ~20-30% clay in mix - always using 2 ball clays (OM4, TN1), maybe kaolin, SG = 1.8-ish. Application to raw extruded clay tile by spray. highest practical % solids mattered.

Tetrasodium pyrophosphate (TSPP) 0.05-0.07 wt% of all solids + sodium-carboxymethylcellulose (CMC) 0.05 wt% of solids. This worked with the local well water — yours will differ so a little +- in dosing is normal. In long storage, the glaze slip could settle a little but remixed fine. In compositions with higher non-plastics a little bentonite (0.05-0.1 wt% of solids) in combination supports stable suspension.

Tried Darvan, other lignins, sodium silicate, alternative phosphates over time. Nothing ever worked better than TSPP/CMC for glaze or engobe slips — or glaze slips with small amounts of frit.

I am amused to see that Ghastly Borate is still out there being used. Sure, why not?


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