Originally Posted by M.D. Holloway
(Post 11703815)
Great questions. A Silicone Spray is a mixture of siloxane (the silicone oil), carrier solvent, and a propellent. The siloxane is very compatible with all sorts of polymers except silicone rubber. The issue may come with the carrier solvent and even the propellant. Some propellants are really volatile and may create some problems.
Lithium grease is typically made with paraffinic mineral oil. Mineral oils can harden and shrink Butadiene (NBR) rubber and can swell and soften Chlorinated Rubber seals. Not the best for natural rubber, SBR, Butyl rubber, Neoprene. The compatible polymers are typically Nitrile and Urethanes.
WD40 is a a petroleum distillate made of Ligroins, petroleum fractions consisting mostly of C7 and C8 hydrocarbons. The fraction is also called heavy naphtha. The formula is 50–60% naphtha, hydrotreated heavy. <25% petroleum base oils. <10% naphtha, hydrodesulfurized heavy (contains: 1,2,4-trimethyl benzene, 1,3,5-trimethyl benzene, xylene, mixed isomers) and 2–4% carbon dioxide as a propellant.
According to their marketing materials, it is compatible with Acetal, neoprene/hard rubber, HDPE, PPS Copolymer Polysulfone, Teflon, Viton. It should not be used with wax polishes and certain wax coatings may be softened. Clear polycarbonate and polystyrene may stress craze or crack.
There is the concept in chemistry that ‘like dissolves like.’ I wouldn’t use WD40 around any rubber pr plastic.
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