Ammonia-dissolved pre-vulcanized latex is of everyday usage to make flexible moulds and peelable protections. In this last case, it is mainly used in ceramic decoration, to carry out resists in the application of engobes, glazes or colourants.
The liquid latex solution is applied with a brush to the dry area to protect in less than 15 minutes, and then becomes rubbery. After application and drying of the layer of engobe, colourant or glaze, one withdraws the solidified latex film by gently separating it from the ceramic object with a pair of small pliers or a blade.
The elasticity of latex facilitates the unsticking and generally the pieces are withdrawn as a whole and in one time.Then the parts protected by latex appear free of engobe, colourant or glaze.
This technique is particularly appreciated when products of very different colours must be superimposed while being well delimited, or if the colour of the ceramic object or shard must appear non-coloured in the case of application by spraying or dipping.
Attention, if the porosity of the object is too important the layer of latex will be difficult to withdraw. Always make a test before launching out in a long work.
It is necessary to proceed in a well ventilated room to avoid breathing ammonia vapor. In the case of a daily and long use of this technique, it will be necessary to consider means of suitable protection and ventilation.
Brushes must be washed between each application and drying of latex.