Thanks for posting that, Deejay, it is a good summary. His description of bentonite grease is perhaps a bit jaundiced - its proponents seem to claim superior wash-off resistance and high temperature performance, and he does not address those claims - but in practice I've always used soap-based greases for mainstream purposes. The actual lubricating properties are determined by the lubricant (oil, perhaps assisted by graphite, lithium or molybdenum disulphide) contained in the thickening medium (soap or clay), not by the thickening medium itself, but where the main problem is dealing with, for example, possible water entry, special circumstances may apply. I'm told Tecumseh had a long-term enthusiasm for bentonite greases.
I think the key point for members to remember is that soap and clay greases are incompatible, so changing from one to the other can be a bit of a project.
