Description
Latex is a pre-vulcanised natural rubber that is stabilised with ammonia. When the ammonia has evaporated the rubber hardens to
form a tough elastic skin. In the liquid state latex is water soluble.
A slightly thickened version is available called Brush Latex. A thin sprayable version is available for spray application;
both versions can be thinned slightly with water.
Application of the Latex to the Article to be Moulded
A thin application should be applied onto the prepared model for the first intricate and detailed skin. This first coating
should be sufficiently fluid to penetrate into all areas of the object to be case and to cover the surface evenly. If a brush
is used to apply the latex, it can help prevent the latex from sticking to and coagulating around the ferrule, stiffening
and binding the hairs of the brush. After each use the brush should be washed out in water and the hardened particles of
latex compound combed out.
To ensure an even and smooth result, it is advisable to begin the latex application from the top of the objects and work down
towards the bottom. Care should be taken with the initial coat that it is smooth and air bubble free as this first coating
determines the surface accuracy and smoothness of the mould.
In most instances, and depending on the size of the mould being made, some 15 to 30 coats will need to be applied. Each coating
should be permitted to dry thoroughly before the application of the next. On drying, the milky opacity or cloudiness of the
rubber disappears and the lates becomes translucent. The drying interval between coats varies, depending on the ambient
temperature, and the thickness off the coat applied.
After the rubber mould has been completed it should be left to cure in place over the model for about two days. When the latex
has thoroughly dried it may be removed from the model by applying a coat of liquid soap (washing up liquid), this will enable
the skin to slip off easily. Latex tends to shrink on drying as the ammonia evaporates. The rubber mould may be cured at
temperatures up to 50˚C.
It is advisable to keep latex moulds out of direct sunlight as the Ultra Violet Light will embrittle the rubber and reduce its
working life. Whilst in most cases the latex rubber mould will not require a release agent, in the area of concrete casts it
may be found advantageous to use Solid Solutions Concrete mould release 600
For more information please contact us at Solid Solutions |
