Defoamers are chemical agents effective in preventing and/or eliminating air bubbles that can sometimes form inside the glaze suspension and/or on its surface: both inside the stirring tank and after application (on the surface of the glaze discharged on the ceramic support).

How does the defoamer work?

The defoamer, since it is water insoluble, is able to destabilize the foaming system by acting on the surface tension of the foam: it brakes the hydrophobic tails of the surfactants leading to the bubble's explosion.

If applied to not very plastic glazes (with a low clay content) or hard glaze (such as glazes containing only frits), the defoamer tends to remain micro-dispersed in the water, sometimes causing defects such as holes or pinholes. The use of defoamer to face the foam promoted by the surfactant can therefore partially or totally solve the problem, but the equilibrium is sometimes rather unstable.