Originally Posted by TheatricalKate
I thought silicone wasn't good to use on buses because it holds water and therefore can encourage rust...?
"Silicone" represents a really broad range of products that are formulated with all sorts of different properties. Silicone caulk as is used in showers and tubs is hydrophilic ("loves water") which means it becomes saturated with water and thereby prevents any more water from getting past it (this is why mold grows in
the caulk sometimes), but when this is applied to metal (instead of plastic or tile) it promotes rust. Silicone lubricant is a hydrophobic powder applied in a solvent that evaporates, and provides some degree of water-resistance in addition to lubrication.