1) How should I mix
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
2) At which concentration should I
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. Concentration control is difficult to
achieve when the coolant is manually mixed in small batches and is
virtually impossible to maintain when untrained operators mix
coolant. The Systems Equipment Division carries a complete line of
automatic proportioning equipment to maintain accurate coolant
3) What is "makeup"
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.
4) What is a refractometer
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. (The
factor for most emulsion fluids is 1.0 so that the refractive index
is the fluid concentration.)
5) Why does my coolant have an
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
- 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.
6) Why are coolants different
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.
7) 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
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.
8) Why am I experiencing skin
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
- Acidity: Acids from any contaminating source
will eventually lower pH and levels below pH 7 will irritate normal
- Solvents: Solvents remove the natural protective
oils from the skin and leave skin more open to chemical
- Metals: Metals like zinc, cadmium, chrome, and
nickel can cause an allergic reaction or even severe skin
- 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
9) 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
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
10) 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.
Never-the-less, 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
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.
11) 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 your Master
Chemical distributor or us directly for Material and Safety Data
Sheets for TRIM® products that you are using or considering for
12) Why are my parts rusting in the
process, or in storage? What can I do about corrosion?
Possible causes of rusting
- Acidity will affect both ferrous and nonferrous
metals; check the pH of the coolant and the bacterial contamination
- Alkalinity can affect non-ferrous metals; check
the pH of the coolant and if high, (see question 10), check for
contamination of the coolant by highly alkaline materials such as
floor cleaners or alkaline cleaners.
- Dissolved salts from the plant water supply or
from heat-treating and plating processes can be a contributor to
- Stacking different kinds of metals in contact
with one another can cause galvanic corrosion (example: steel and
- Unless properly processed, wood, paper and
cardboard are acidic and contain corrosive salts and should not be
used as separators in tote boxes. Use an acid free plastic mesh.
Tote boxes should allow parts to dry rapidly.
- Parts should not be blown off with an air hose.
Flush chips off with a coolant hose or dip the parts in clean
coolant to remove chips and/or swarf.
- Do not use active sulfurized/chlorinated cutting
oils in conjunction with water-soluble coolants.
- Poor coolant concentration control.
- Germicides and other coolant additives may be
corrosive; add them only at the proper concentration.
- The improper application of rust inhibitors;
coolants are designed to provide short term, "in process" corrosion
inhibition. Long term storage (two weeks plus) will usually
necessitate the application of other corrosion inhibitors.
13) If I sent a coolant sample to
Master Chemical where can I get my lab report and what does it
Lab reports are generated by Master Chemical's Technical Services
Laboratory and can be obtained through your local TRIM®
Distributor. Lab reports will list general results like pH,
conductivity, percent of tramp oil, bacterial levels, and
concentration by refractive index. Your Distributor's coolant
specialist or your Master Chemical District Manager will help you
interpret the results.
14) Why do I have
Most coolants will foam to some degree because
the lubricants and wetting agents (soap like materials) present
will form bubbles when they are agitate in the presence of a gas
(air). In certain operations, controlled foam is necessary for
functional requirements, but excessive foam can be a serious
problem. Generally, large bubbles are unstable and will break
readily. Tight, "shaving cream" bubbles are stable and will not
break and present a problem by spilling out of the sump on the shop
floor causing housekeeping problems. More importantly stable foams
do not cool or lubricate and can cause tools to break or ruin
surface finish. Every foam problem is an individual circumstance
and has to be considered on its own merits. Therefore, if foaming
occurs check for:
- Air leaks in valve stems from loose
- Shaft packing in pumps.
- Pipe unions and connectors.
- Pump by-pass valves opening and "jetting"
high-pressure coolant back into the coolant sump.
- Excessive cascading or "dropping" of the coolant
to the tank surface.
- Pump cavitation.
If these problems cannot be handled by mechanical
adjustments, then contact your Master Chemical District Manager or
your TRIM® Distributor for recommended TRIM®
TC Antifoam that will help to control the foaming problem. They may
recommend a lower foaming coolant that would be better suited to
15) What is antifoam? How do I use
it? How much do I add?
Antifoam is a product designed to knock down
foam in coolant sumps by rupturing the foam bubble cells. It is
most generally applied directly into the system immediately
upstream of the foam or directly onto the foam.
Add antifoams at the lowest recommended dosage.
Too much is not always better. Almost invariably antifoams will be
filtered out of the coolant or they will be carried out on chips
and parts. Plan on adding them periodically.
16) Which product do you have which
is like the one I am using now?
Due to the many different types of operations
and the variety of material types, product recommendations need to
be made carefully. It is entirely possible that the product you are
currently using is not ideal for your operations. If you can supply
information on your work materials, your machines, your tool
materials and the operations you are performing, your TRIM
Distributor will be pleased to recommend a product which will be
matched to your objectives. Your local Master Chemical District
Manager can usually recommend a product based on the information
supplied by firstname.lastname@example.org
17) Why is tramp oil a problem in
Tramp oils (lubricating, cutting and hydraulic
oils and greases) have serious, adverse effects on water miscible
cutting and grinding fluids. Tramp oils cause a loss of wetting and
thereby will degrade both the workpiece surface finish and tool
life. They also reduce the cooling effect of the fluid that also
impacts tool life. Tramp oils will impede filtration and contribute
to unfavorable residues on machine tools and workpieces.
Environmentally, tramp oils contribute to smoke and oil mist and
stimulate the growth of bacteria.
These adverse effects are proportional to the
amount of tramp oil present and, therefore, are most pronounced on
those machines which leak the most oil. As bad as these effects are
on "individual sump" machines, they are even worse in central
systems where continuous recirculation through powerful pumps keeps
the oil emulsified.
Master Chemical manufactures oil skimmers,
and coalescers and sells and services high-speed, disc-bowl
centrifuges to keep tramp oil levels under control. They are
available through your local Master Chemical Distributor.
18) Why does the machine sump smell
badly after a few days shut-down?
When a machine is shut down for a few days
some of the tramp oil in the fluid separates and rises to the top
of the sump sealing off the fluid from the air. Anaerobic bacteria
grow and reproduce without the need of oxygen. As a matter of fact
oxygen actually inhibits their growth. These bacteria in the
stagnant fluid now begin to grow and release hydrogen sulfide (H2S)
gas that dissolves in the coolant. When the coolant pumps are
turned on at the end of the shut down the dissolved H2S is released
to the atmosphere. H2S has the characteristic odor of rotten eggs
and the human nose can detect it at the 1-2 parts per billion
level. Talk to your Master Chemical District Manager or your TRIM®
distributor about ways of controlling this persistent
19) How much of TRIM® TC
______ do I use?
TRIM® TC additives are designed for
different applications. Each product has a different addition rate.
Consult the product's Data and Information Sheet. Specialty
20) Can I mix one type of fluid
Water miscible fluids are all different by
design. While most products are compatible it is advisable to
consult Master Chemical Corporation for specific instructions on
mixing different fluids together.