DoALL Coolant and Cutting Fluids FAQs

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Coolant Pump Leakage, Even After Seal Replacement

DoALL Models: Vertical Contour saws, Power saws and Grinders

Beware of using an incorrect procedure when installing replacement coolant pump seal.

Be sure the seal you install is new stock, as there were manufacturing issues with springs in the past. Then install the seal according to the following instructions:

1. Remove pump from the impeller housing.
2. Loosen set screw holding impeller to pump shaft, then remove impeller.
3. Remove entire seal.
4. Clean and polish pump shaft.
5. Lubricate shaft OD (outer diameter) with oil, then install base portion of the seal – Be sure it bottoms firmly.
6. The next section of seal must be pressed firmly against the base section for a good seal.
7. Add spring and washer.
8. Replace impeller with a minimum clearance between the impeller and motor adaptor. Tighten set screw.
9. The gasket (DoALL replacement part #: 2928) should be replaced when new seal is installed.

Referenced from DoALL Historical Service Tip Sheet #86

How important is coolant in band sawing?

The term coolant implies that drawing off heat is its only purpose.  Cutting fluid is a more precise term.  Sawing brings the work and saw teeth together under heat and pressure, and that can weld the two.  Components of cutting fluids include additives that prevent chip welding, lubricants that reduce the amount of heat generated, and water that draws away much of the heat that is generated.   Use a good, heavy-duty cutting fluid.  Get a refractometer to check and maintain the fluid mix ratio according to the manufacturer’s recommendation.

What’s the right way to replace lost cutting fluid?

Keep in mind that you are replacing straight mix lost to spilling as well as water lost to evaporation.  The mix you add will be less concentrated than the original, generally by about half.  Use a refractometer to guide you in mixing the make-up fluid and to confirm the end result.

Can one metal working fluid be used on top of another metal working fluid?

We strongly recommend performing a “clean and dump” prior to using new coolant over existing coolant.  However, if the customer does not want to do this, then the following questions and answers need to be taken into consideration before dumping new coolant over existing coolant:

  • Does the customer have poor coolant housekeeping habits?
  • Do you detect an odor from the sump?
  • Is there significant tramp oil?

If you answered yes to these questions then a clean and dump needs to be performed.  Otherwise, the new coolant will not perform properly.

NOTE:  Dumping new product over existing product has to be in the same category.  You can only do this if you are going from a synthetic to a synthetic; semi-synthetic to a semi-synthetic; or soluble oil to a soluble oil.  

How do you control bacteria and mold?

The best way to control bacteria and mold is to consistently maintain your systems.  This is done by monitoring the concentration at least a minimum of twice weekly.  Skim off the tramp oil and make sure the fluid is aerated throughout the system.  If this is not done it is best for the end user to resort to a biocide or fungicide depending on the type of biological growth present.

What causes dermatitis when using metalworking fluids?

Ninety-five percent of dermatitis cases are the result of elevated coolant concentration.  High concentrations have a higher alkalinity level; therefore causing irritation on skin that comes in contact with the fluid.  Dermatitis can also be caused by bacteria in a sump.  It is for these reasons that it is important to stress good maintenance practices.

What causes mix instability in soluble oils?

Mix instability can occur when the operator adds the water to the coolant instead of adding the coolant to the water.  In soluble oils this causes an invert emulsion that can interfere with the coolant working properly for your application. 

What is a refractometer?

A refractometer is a hand held instrument that measures how light is refracted through a liquid.  This reading is then converted to the concentration of the metalworking fluid within the sump.   It is important to check the concentration levels, as low refractometer readings mean you lean your alkalinity reserve causing rusting that will encourage bacteria.

What causes foam?

Foam can be caused by soft water, high-pressure machining, soaps or contaminants within the system. 

What causes corrosion?

Corrosion is caused when the concentration of the metalworking fluid is too weak or too lean.  Contamination levels and plant environment (humidity) can also cause corrosion.  Corrosion can also happen when parts are handled improperly.  As soon as corrosion is noticed, intervention is necessary to determine the cause and proper corrective action.

Can I use bleach to clean my sump?

We strongly recommend using DoKleen 3004 to clean the sump. Bleach combines with the calcium and magnesium in water leaving behind salt, which is corrosive and exacerbates rust.