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FAQ:

Fluids



How should I mix TRIM® products?
Mixing is crucial to maintaining stability in cutting and grinding fluids. Proper mixing instructions are available on all Master Chemical Data and Information Sheets. For optimum performance and maximum life, coolant concentrates should be mixed with chemically pure water produced by deionization or reverse osmosis. It is a general rule that concentrates should be added to the water last and mixed thoroughly. One way to remember the proper sequence of addition is to remember "O.I.L.", meaning "oil in last". Special mixing devices and proportioners like the UNIMIX™ and Master Mix™, which automate the mixing process and minimize the waste of concentrate, are available from Master Chemical.

At which concentration should I be running?
Master Chemical products are specifically designed to be used at a number of different concentrations. Each product and application will have an ideal concentration ratio for the metalworking fluid. The concentration will affect sump life, tool life, and surface finish. Master Chemical's Data and Information Sheets give examples of applications and their corresponding concentrations. Maintaining proper concentration is essential for efficient and trouble-free results from water-miscible cutting and grinding fluids. Master Chemical's Technical Service Laboratory estimates that well over 80% of the "trouble calls" received are directly or indirectly attributable to poor concentration control.

What is "makeup" concentration?
When water miscible coolants are used in machining and grinding operations the volume of fluid in the coolant sump decreases due to the physical loss of the fluid (fluid is carried off on chips and parts) and water evaporates because it absorbs heat generated in the machining or grinding operation. Proper operation requires that the fluid level is maintained at some minimum level and so "makeup fluid" must be added to replenish coolant carried out on chips and parts. Since the loss of water by evaporation causes the fluid in the sump to increase in concentration the "makeup fluid" will always be mixed at the same concentration less that of the recommended operating concentration. For example, if an emulsion coolant is to be run at 5% volume to water then the "makeup" concentration for that fluid will generally be 2.5-3.0%. Check your product data and information sheets for recommended working and "makeup" concentrations.

What is a refractometer factor?
The refractometer factor is used in determining concentration of a metalworking fluid. Each Master Chemical product has a refractive index factor for determining concentration. Consult the Data and Information Sheet for product specific refractive index factors. Multiply the refractive index (refractometer reading) by the refractometer factor and the result is the concentration of the working solution in percent.

Why does my coolant have an unpleasant smell?
An unpleasant coolant smell is most likely attributed to anaerobic bacteria. Bacteria produce waste products, which often contain sulfur and exude the "rotten-egg" smell. Bacteria are major contributors to coolant failure. They chemically alter coolants and destroy the lubricants and corrosion inhibitors in the process. They also pass off corrosive acids and salts into the coolant, which can lead to low pH and corrosion problems. The bacterial growth can be minimized by:

  • Maintaining proper coolant concentration.
  • Good housekeeping practices (cleanliness).
  • Preventing or minimizing contamination.
  • Good filtration of the coolant and continuously removing chips.
  • Thorough, periodic sump clean-outs.
Oftentimes, "cover-ups" which are perfumes, can be used to mask odors but they are not a cure and their use can lead to more serious fluid problems later.

Why are coolants different colors?
Most coolants exhibit colors and odors that result from the chemicals from which they are blended. But sometimes metal cutting fluid manufacturers use dyes and colorants to give them an aesthetic appeal. They are also helpful in identification of products for companies which use a number of different products. Machine operators sometimes use color intensity as an indication of coolant concentration. Color intensity is not a good indicator of concentration as tramp oil can absorb the dyes used, and some work materials (such as cast iron) can "mask" the dye. Even with dyed coolants it is necessary to check fluid concentration properly periodically.

What is the residue in the sump or machine tool?
Residue is the material left behind on the machine and workpieces after the water evaporates from the coolant solution. Residues should never interfere with the smooth and proper machine tool function but more importantly the residue should enhance the machine's operation. Residues may be classified as:

  • Fluid
  • Soft
  • Hard
  • Gummy
  • Crystalline
For optimum machine tool functioning, oily, non-gummy residues are preferable. If a residue is hard, gummy or crystalline, it can cause a machine's moving parts to "stick" or "freeze" and may cause a machine malfunction. A moderate crystalline film may be tolerated on certain types of surface grinders but such a residue could cause a major problem on a 5-axis machining center. In other words, the type of machine must be considered when selecting a fluid because the type of residue may dramatically affect the machine function.

Why am I experiencing skin irritation?
Occupational Dermatitis is a term used to describe any abnormality of the skin induced or aggravated by the work environment. Dermatitis is somewhat more specific in that it refers only to inflammation or irritation of the skin. There are four possible mechanisms by which dermatitis may be introduced:

  • Mechanical injury caused by friction, pressure, or trauma, including abrasion.
  • Chemical attack from the precipitation of protein by acid.
  • Physical agents including excessive heat or cold, radiation, or electricity.
  • Biological agents like insect bites or plants, such as poison ivy, poison oak, and poison sumac.

The following is a list of the more common causes of dermatitis in the metalworking environment:

  • Alkalinity: Prolonged contact with highly alkaline materials.
  • Acidity: Acids from any contaminating source will eventually lower pH and levels below pH 7 will irritate normal skin.
  • Solvents: Solvents remove the natural protective oils from the skin and leave skin more open to chemical attack.
  • Metals: Metals like zinc, cadmium, chrome, and nickel can cause an allergic reaction or even severe skin irritation.
  • Straight cutting oils: Many straight cutting oils contain active sulfur which will release acid when in contact with water. Coolants contain alkaline materials and can contain detergents or emulsifiers. At high concentrations these can irritate and dry the skin.
  • Concentration: High concentrations should be avoided and not exceed the maximum recommended concentration.
  • Filthy coolant: Suspended metal fines and abrasive grain can wear away the skin and do serious injury. Filter coolant to remove these abrasive particles or change the coolant more frequently.

Is coolant a hazardous waste and how do I dispose of it?
Used coolant should not be introduced directly into sanitary or storm sewers because of contamination from various oils and metal particles. Since all used coolants contain petroleum oils, either by virtue of their composition or because of tramp oil contamination, they must not be emptied into sanitary sewers without treatment.

Most smaller metalworking plants pay to have used coolant hauled away for proper waste treatment and ultimate disposal. It is important to note that legally, title to waste does not pass to the hauler but remains with the generating facility. For this reason it is important that only reputable, licensed firms be engaged for disposal processes only.

Other options for disposal include: evaporation, or incineration and chemical treatment to separate oil and fluid concentrates from the water so that the water meets local sewer codes. Check with your local waste ordinances prior to disposal.

Will mist from the cutting fluid hurt me?
Master Chemical is the first American metalworking fluid manufacturer to begin testing its fluids for their affects on human health. In 1953, we began testing our fluids for dermal safety on human volunteers and today we also have them tested for eye and skin irritation as well as for acute inhalation and oral toxicity. Since Master Chemical is totally committed to producing only safe products, all of our formulas must be non-toxic as well as be non-irritating at their maximum recommended concentration. Additionally, Master Chemical has a firm policy of not using any ingredients with known or even suspected adverse effects on human health.

Nevertheless, once in use metalworking fluids become contaminated with lubricating and hydraulic fluids from machine tools, metal fines, abrasive grain and bond, and even some metal ions from the processed parts will eventually dissolve in the fluid. Because of the variety of materials which can contaminate coolant solutions, it is impossible to evaluate the safety of these used fluids in the laboratory.

There are no scientifically definitive studies that indicate coolant mists generally present a significant hazard to machine operators. The exception to this is that coolant used to grind carbide cutting tools under production conditions can sometimes dissolve appreciable amounts of the cobalt binder, and mists containing high levels of cobalt can produce what is called "hard metal disease," which can seriously impair lung function. For this reason, mists from coolants used to grind carbide should be avoided and the fluid tested regularly to monitor cobalt levels.

Although coolant mists generally have not been shown to be hazardous, when dealing with a scientific unknown it is always best to err on the side of caution. For this reason Master Chemical recommends avoiding inhaling coolant mists as much as possible. We further recommend that machine enclosures be kept closed during the machining or grinding operations and that enclosures, gaskets, and seals be maintained for proper functioning to minimize the escape of mists into the shop atmosphere. We further recommend that plants take the necessary steps to ensure that there is adequate fresh air make up and ventilation.

The Occupational Health and Safety Administration currently has in place a regulation requiring plants to keep oil mists at or below 5 mg of oil per cubic meter. Oil mists are primarily a concern with machines using straight or neat oils. However, when coolants become heavily contaminated with tramp, lubricating and hydraulic oils these oils can vaporize when splashed onto hot tooling or when atomized in grinding operations. For this reason (and others) Master Chemical recommends that tramp oil leakage be minimized however possible and that machines with hydraulic leaks, which cannot be fixed, be fitted with skimmers or coalescers to remove the contaminating oils. Additionally, since some oils will tend to emulsify in most coolants, we recommend that coolants be recycled periodically through a high-speed, disc-bowl centrifuge to remove emulsified tramp oil. If a plant does not have recycling capabilities then coolants should be disposed of properly when tramp oil levels become significant.

May I have an MSDS (Material and Safety Data Sheet) sheet?
MSDS sheets are made available by all product manufacturers and must contain any hazardous ingredient information along with threshold limits on ingredients. Contact us directly for Material and Safety Data Sheets for TRIM® products that you are using or considering for use.



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