What are silicones and what one is best for your requirements?.
Silicones are produced by reacting silicon—one of the earth’s most common elements- with methyl chloride and further reaction with water which removes the chlorine atom. This reaction produces polymers that are resistant to high and low temperatures and find applications in thousands of products in applications including health care, aerospace, personal care, electronics, transportation and construction.
RTV Silicone (room temperature vulcanization silicone) is a type of silicone rubber made from a two-component system (base plus curative; A+B) available in a hardness range of very soft to medium – usually from 10Shore A to 40 Shore. RTV silicones can be cured with a catalyst consisting of either platinum or a tin compound with mix ratios stated on the kit.
What’s the best for you ?
Deciding on the right silicone is easier than it seems, for example let’s narrow it down, If you have something to mould that has very fine detail with undercuts then you need to look at a more flexible silicone with a low shore hardness, this will help you when de-moulding. So based on this you should be looking at somewhere 15 Shore A or below. With this said and using this idea you can look at the other end of the spectrum, if you want to make a block mould without using a fibre-glass case then you’d almost certainly need a silicone somewhere around the 35-40 shore A hardness. It’s that easy when you’re looking at shore hardness and anywhere in between ie 20-30 shore A are ideal silicone shore Hardnesses for general purpose mould making. Lastly choosing between Condensation Cure silicone & Addition Cure is pretty straightforward too, in both sections on silicones in our website we have given you an Insight into which is best for you and worthwhile reading.
Key points –
Translucent silicone ideal for pigmenting/colouring
00-10 shore A – prosthetic grades ( translucent & platinum )
10-18 Shore A – fine detail and under-cuts
20-30 Shore A – general purpose mold making
30-40 Shore A – block molds & firm 2-part molds.