Application Guide

Which coolant is right for me? Most Coolant Manufacturers offer three types of metalworking fluids

Emulsified oil (sometimes called soluble oil), semi synthetic, and synthetic coolants are the three most common alternatives. All of these alternatives require additional components for improved machining as well as foam control, biological control, pH stability and corrosion control. 

Soluble Oils – These types are very common and generally form a milky, opaque fluid. Typically soluble oils are 50% oil, or more, and balanced by emulsifier and additives. Most heavy duty soluble oils have added chlorine to enhance extreme pressure machining. Oil provides lubricity for much of the machining process as well as excellent corrosion control for the machine and its parts. Unfortunately, oil emulsifiers are known as a favorite food source for bacteria, and often impede the heat dissipation process.

Semi-Synthetics – This type of coolant contains both oil and a synthetic (polymer). A semi-synthetic coolant can contain anywhere from 5% oil to 35% oil. The smaller percentage of oil in semi-synthetics allows for heat to be dissipated much faster than with soluble oils, improving tool life and finish. Much like soluble oils, chlorine is sometimes added to improve heavy machining performance.

Synthetic – Synthetics often contain as many as 17 ingredients, including polymers, which are used to replace the oil and cutting additives found in soluble oils and semi-synthetics. Without oil, additives are required to control corrosion. The historic problems of corrosion control and hard deposits on the machine tool have improved with the development of modern coolants. Some modern formulas actually emulsify a limited amount of oil to help improve performance.   Without oil however, synthetic coolants can offer superior cooling with extended tool and sump life.