Working with silicone rubber.
People that have never worked with
silicone rubber should definitively make some little tests without using original valuable moulds.
It is very important to facilitate compliance with safety regulations such as
the use of protective gloves and glasses. The accelerator is caustic and might spurt out at the beginning when you mix it incautiously. The accelerator must not touch your eyes!
The basic compound must be mixed well (most suitable is the use of a slow motor but it‘s also possible to mix it
manually). Make sure that you comply exactly with the mix ratio of the basic compound and the accelerator. Moreover, it must be mixed very well.
Silicone from www.candlecraftcenter.com is very easy to remove from any kinds of moulds. Mould release agents are generally unnecessary (but you definetively need it when you use silicone on silicone).
If you follow these rules you'll end up with one of the best, most robust and age-resistant types of silicone rubber available on the market!!
Tips on how to make moulds with two basins:
First of all you have to position the object you want to form firmly in your mould box (i.e. with wire) so that the parting line is horizontal and that
there is a space of more or less 1 cm below the object. Please make sure that the object cannot bloat!
The mould box must be absolutely impervious! Pour the compounded silicone rubber until it reaches the parting line.
Leave it for one day. Insolate the parting line with Cancol. Fill the upper layer (top half) with silicone rubber. Leave it for one more day and remove
A tip on how to make sure that the two halves of moulds with two basins fit together exactly:
Place some wooden marbles (15mm) on the liquid rubber in the lower part of the mould. Take the marbles out again just after the setting (and of course
before pouring the upper part). Thus you’ll have hemispherical cavities in the parting line and later on adequate hemispherical bumps in the upper layer.