On 01/10/2012 18:00, The Medway Handyman wrote:

Sounds daft, but silicone is used as a mould release agent.

I can never work out how come silicone sealant is so sticky when
silicone spray is so slippery?

It's all down to chemistry. The air cure stuff as used in sealant
cartridges and which smells of vinegar sticks to almost everything when
it sets. The two-pack stuff (RTV, short for room temperature
vulcanisation) doesn't stick to anything, hence is used for things like
dental moulding. Silicone oils are not particularly good lubricants for
metals (compared to mineral oils) but are very good on most plastics.