Saf-T-Cool 420 forms a premium quality micro-emulsion for machining and grinding all types of metals (except magnesium). Starting dilutions for machining operations should be between 5 – 10%. For grinding operations, the suggested starting dilutions should be between 4 – 6%. Make-up fluid is typically added at half the target concentration. For proper mixing it is recommended that Saf-T-Cool 420 concentrate be added to water with agitation. It should be stored indoors above 40° F.