What does it mean that water is hard and how does it affect the emulsion prepared?
Permanent hardness of the water is an expression of amount of calcium and magnesium in water and this is expressed as French Hardness quality. Minerals like calcium and magnesium in water dilute the effects of emulsion producing additives in metal process fluids and prevent the fluid from emulsifying with water. In emulsions prepared with such water some oil separate from emulsion and float on the surface. Thus, lubrication, rust preventing and refrigeration features of water are diluted. By the way, minerals like calcium and magnesium in water are such a good nutrition for bacteria and bacteria propagate in emulsions prepared with such water in a short while. Bacteria cause molds as well as dilution of the effects of rust preventing additives in emulsion and oxidation problems occur. For those reasons, hardness of water used in emulsion preparation should not exceed 20 French Hardness in order to operate emulsions free of problems and to get long effective life span. WHATEVER SOURCE I
