Originally Posted by
geargnasher
MJ, I've explained basic soapmaking several times on this thread. Metal soaps are made by reacting a metal hydroxide with a fatty acid, almost always stearic acid, which is present in beef tallow and castor oil in large percentages. If you have too much stearic acid, there won't be enough hydroxide to react it all, and residuals will have either an acidic or basic nature depending on which way the reaction was NOT stochiometric. You don't want leftover acids or bases in your lube. This is why we're using industrial-grade finished metal salts. Grease made in industry is made from scratch with EXACT quantities of KNOWN components to ensure complete reaction. We don't have the ability at home to get that close, so using finished stearates and testing for corrosion anyway is the safest route.
Gear