TOOLTALK What to Know About Refractometers Refractometers are handheld, lightweight, and mobile instruments to help you find the concentration of water-soluble fluids like detergents, antifreeze, machine tool coolants, hydraulic fluids, and battery acid. This is because refractometers are commonly used in the food, chemical, and manufacturing industries. How to Use: Place a few drops of fluid on the prism and bring the refractometer to the light. Refractometers give you the Brix scale, not a percentage. Working Concentration: Fluid in your tank should be at the recommended concentration. Makeup Concentration: As water evaporates and the concentration changes, it is advised to add fluid in a makeup concentration. This is typically half the recommended working concentration. How to Determine Which Scale to Use: Refractometers use the Brix scale which was originally used to measure sugar content in water solutions but now we use it for metalworking fluids. Some coolants use a blend measure of 1:1 on the Brix Scale. Make sure you check the product data sheet for the correct refractometer factor. You will then multiply the factor by the reading on the scale to determine the percent concentration of the solution. To determine which scale is best, you divide the required concentration by the refractometer factor. (Example: Refractometer factor is 1 and you need 10% concentration. 10/1=10 so your scale will need to go up to 10. •Sometimes when your concentration is too high, it will not register on the scale. •If you are getting inconsistent results, your refractometer may need to be recalibrated. Once the line of the coolant becomes blurred, it is time for new coolant. 30 30 0 New Coolant 0 Old Coolant SharpCool® GP Synthetic Low Foaming Multi-Purpose Metalworking Fluid Suggested Operating Concentration Suggested Concentration Range: 4.0% - 10.0% Light 4.0% - 6.5% Operations Moderate 6.5% - 8.5% Heavy 8.5% - 10.0% Mixing Recommendations •Add concentrate to water (never the reverse) and stir until uniformly mixed to ensure the best possible working solution. •Use premixed coolant as makeup to improve coolant performance and reduce coolant purchases. The selected makeup should balance the water evaporation rate with the coolant carryout rate. •To improve sump life and corrosion inhibition while reducing carryoff and concentrate usage, use mineral-free water. Concentration Chart Concentration Percentage 10.0 8.5 7.0 5.5 4.0 1.2 1.7 2.1 2.5 2.9 Refractometer Reading Concentration Percentage = Reading x Factor % Brix Refractometer Factor = 3.4 Looking for Metalworking Tools? Contact Fastenal at 844.365.8665 or cuttingtoolsupport@fastenal.com Go to fastenal.com/metalworking for previous Tool Talks
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