Quote Originally spoken by alphax View Post
I've been researching silicone fluids and although all of them seem to be pretty safe, only some 350cSt silicone fluids (dimethicone) are rated as "food grade". cSt stands for cubic Stoke, a measure of viscosity. 350cSt is approximately the viscosity of medium weight motor oil.

I speculate that this is because 350cSt silicone fluid hasn't been diluted with cyclomethicone, which is somewhat volatile, a skin and respiratory irritant.

Dimethicone seems to be available for purchase cheaply at USD$45/gal. as a cosmetic and lotion ingredient.
Interesting this because one of the products I have used with reasonable results is Millenium ID. This lists its Ingredients in order as Cyclomethicone, Dimethicone and Dimethiconol. The former is the dilutant alphax mentions as being a skin and respiratory irritant. I haven't experienced any problems personally but I suppose some people might. Anyway one of the warnings on the label is "should irritation occur discontinue use immediately". It does also warn about the persistent slipperiness so I guess they've got themselves covered.
I have searched for Dimethicone sources in the UK and so far only come up with one source Basildon Chemicals but they are a manufacturer of chemicals rather a maker/distributor of products to the public. Anyway in the course of this research it is pretty apparent to me that not all Silicones lubes and hence sprays are the same but use many of the same ingredients in varying grades of viscosity etc.
Having said all that because of the persistent nature of silicon based lubes I am actually in the process of chlorinating a fair amount of my gear and going to water based lubes and shiners.