Addition cure silicones, also known as platinum cure silicones, have without doubt the longest lifespan of all the silicones available. They also have minimal to zero shrinkage so are ideal when accuracy of casting is required weeks or months later. They are great for mould making for a variety of materials and industries, from epoxies, polyesters, plaster, and also low melting metals where heat tolerance is required. Industries are equally varied from rapid prototyping to Formula 1 or SFX applications, where a skin-safe silicone is needed for life-casting.
With the fantastic mechanical properties platinum cure silicones offer, they do need to be used carefully to avoid inhibition. Inhibition is when a platinum cure silicone doesn’t fully cure due to a form of contamination on the surface of what you are attempting to mould. Though it may look fully cured on the surface, when you separate it from the item you were moulding you will find a tacky surface - namely inhibition.
This is something you must be aware of when using platinum silicones and care must be taken - a good example is latex or moulding directly from a clay with sulphur. Both of these will cause the Platinum Cure silicone to inhibit. There are a number of solutions available to avoid this from happening but please if in any doubt contact a member of Mouldlife’s technical team if unsure at any time.