If the master is dipped for a longer period a thicker coating will be obtained, needing a longer drying time. Before attempting to peel the mould from the master, apply talc or washing up liquid over the surface to prevent it sticking to itself when it is peeled. Drying can be speeded up by using gentle heat up to about 70✬ - 75✬. at normal room temperature (20✬), turning from white to a semi-transparent creamy yellow colour, and ready to peel from the master in 2-3 hours. The Latex should be touch-dry in 10 mins. Re-dip in the Latex and leave for 15-20 minutes, remove and allow any surplus to drip off a mould thick enough to be used should have been formed. As this is being done the Latex will quickly turn to a paste which will prevent the release of further air. To overcome this, re-dip for a few seconds, remove from the Latex and with a brush, stick or palette knife, burst the bubbles as they form and spread the Latex over the surface. However, as the moisture enters, it replaces the air already there, thus forcing air bubbles to form in the Latex. This is best carried out with porous masters, as the porosity draws moisture from the Latex, thus causing it to thicken on the surface. Plasticene masters can be used with Latex but may result in a reduced mould life. Some metals react with Latex resulting in weak moulds. The process is the same as for plaster and clay.įor these type of masters the paint on method will be necessary. This material is suitable but should be allowed to dry out or fired before dipping in Latex.Įxperimental work has shown that moulds can be made on wood masters, which must have a smooth surface and be of a porous nature. Probably the most suitable material as the porosity of the plaster draws moisture from the Latex causing it to thicken. The choice of materials is quite important. When considering making a latex mould a suitable master must be either acquired or created. Latex is easy to use, is relatively strong, and will give good definition and accuracy of reproduction. This extremely versatile material is widely used in such diverse fields as the manufacture of moulds for garden ornaments to the production of theatrical masks. Latex Liquid Rubber is a prevulcanised emulsion which will air dry on the surface of a master pattern to form a highly flexible thin rubber skin.
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