How Water Affects Coolants and Cleaners

Keeping up on your coolants and cleaning solutions is very important. If your coolant or cleaning solution is not changed regularly or mixed properly it will affect their performance. It can even affect your health if not maintained properly.

The biggest factor in having the proper coolant mix is the water. What? Water is water right??? Not necessarily. Not all water is created equal and some water is not just water.  Contaminated water can contribute to bacteria growth in the machine coolant. Water can be too hard or too soft and can even cause health problems for you and your employees.

Hard water can and will

  • Affect the quality of the end product
  • Increase maintenance costs of machinery
  • Decrease process efficiency
  • Corrode machined or ground parts
  • Increase the growth rate of bacteria and fungi
  • Decrease useful life of the coolant

Goodson recommends you get your water tested for hardness. You can get your water tested by your local water softening source, a local college or university or the County Extension Office for a small fee or maybe even at no charge. Test kits are also available from several sources online so there’s really no reason to not have your water tested.

Total hardness indicates the presence of dissolved minerals and their salts in water. Predominant ions are calcium and magnesium. Other ions contributing to hardness include iron, zinc, aluminum, potassium and silicon. Total hardness is reported in parts per million (ppm) of calcium carbonate (CaCO3). It can also be reported in units called grains. One grain of hardness is equivalent to 17 ppm of calcium carbonate. Water hardness is typically defined using the following scale:


0 – 49  Very soft
50 – 124 Soft
125 – 249 Medium
250 – 369 Hard
370 and above Very hard

The parameters that should be evaluated continuously are hardness and pH.

The pH of water indicates whether it is acidic (pH of 0.0 to 7.0), neutral (pH of 7.0) or basic or alkaline (pH of 7.0 to 14.0). Most water used commercially in the United States exhibits a pH range from 6.4 to 8.5, depending upon the original source and type of pretreatment conducted by the local water authority. Water used for coolants should exhibit an optimal pH range from 7.0 to 8.5.

Goodson offers pH test strips that have a range of 0 to 14. pH test strips are very easy to use just dip the strip in the coolant or water to be tested for a couple seconds and remove shake excess off and compare the color of the strip to the color chart that comes with the strips.

When mixing coolants you always want to follow the manufacturer’s recommended mix ratio. Goodson has a limited supply of refractometers to check the % of coolant to water ratio. This is simple to use, you take an eye dropper that comes with the refractometer and put a couple drops on the lens. Close the lens and look towards a light source and read the scale of %. I like to see 2 to 2 ½ % coolant. When coolant gets above 3 ½ % it starts to gum up and get sticky. It will start to gum up the bed and ways.

To help combat bacteria and fungus in your coolant Goodson offers a Micro Biostat that you can add to your coolant to help control the bacteria and fungus.

On the opposite side of hard water is soft water, now being too soft can cause issues as well. You have to have a happy medium for everything to work together and have great results.

Soft water may degrade the performance of all fluids by promoting the formation of foam. This condition is especially likely when using synthetics in grinding operations and semi-synthetics and soluble oils in both machining and grinding applications. Foam can drastically impair fluid performance by contributing to poor wetting and coverage properties, which diminish lubricating, cooling and proper film coverage for in-process corrosion protection. Foam can also hamper fluid detergency, making it more difficult to handle and filter swarf.

When dense foam forms, it can lessen the filtering capabilities of a system by interfering with indexing mechanisms and by creating poor filter beds. Foam can also suspend tramp oils, preventing skimmers and other mechanical devices from removing them effectively. Tramp oils can act as a matrix, becoming finely suspended on a dense bed of foam. This development further intensifies a dense foam layer. Excessive foam can also lead to housekeeping issues by causing system barges and return lines, such as floor troughs, to overflow. Foam can also cause pump cavitation, creating excessive wear and premature mechanical failure.

Goodson also offers a Defoaming Agent to help with excessive foaming in your coolant. With the Defoaming Agent you will want to start with 1 ounce in 50 gallons. Keep in mind if you use to much it will have a reverse effect and create foam so start small and creep up on it, more is not always better in this case.

So overall keep in mind if you are having some issues with your coolant whether it’s in your flywheel grinder, belt surfacer, crank or cam grinder it’s important to know what quality water you are using to mix with your coolant.

For any questions you may have on grinding coolants contact Goodson Tech Services at 800-533-8010.

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