Glass Cloth Coating by Dispersion

Glass cloth has a smooth surface and is porous. It does not ionize in water or absorb the polytetrafluoroethylene dispersion. It picks up a small amount of dispersion per pass, therefore requiring multiple passes (up to a dozen) to obtain a smooth surface, if that is required. 

A dip tank water jacket is sometimes necessary to maintain the dispersion temperature at 20°C to 25°C. 

The dip tank should be designed with a minimum exposure to ambient air to avoid evaporation of water which would change the resin concentration, thus wet coating thickness. 

The oven should have three zones consisting of drying, baking, and sintering. 

An annealing chamber is sometimes installed at the exit of the sintering oven to prevent the coated glass from cooling too rapidly to avoid wetting difficulty during the second pass coating. 

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