GRINDCLEAN RESOURCES HUB

This is going to depend on the following variables

What material(s) are you grinding? (e.g., carbide, HSS, stainless steel, titanium, aluminum)

What type of grinding are you doing? (e.g., surface grinding, centerless grinding, cylindrical grinding, creep feed, tool & cutter grinding, burr grinding)

What type of machine are you using? (e.g., manual grinder, CNC, high-speed grinder)

Are you using a diamond or CBN wheel, or a conventional abrasive?

Do you prefer oil-based or water-based coolant?

Any specific needs like:

• Maximizing lubricity (for better surface finish)

• Best cooling (to avoid burning or cracking)

• Minimal foaming

• Low maintenance / long sump life

• Health & safety/environmental friendliness (e.g., low misting, non-hazardous)

We can help you with application specific coolant selection.

Good question — and the honest answer is: it depends on how well you maintain it.
Here’s a clear breakdown:

You should change your coolant when:

• pH drops or rises outside the recommended range (typically pH 8–9.5 for grinding coolants)

• Concentration drops too low (from dilution) or climbs too high (from evaporation)

• Coolant smells bad (bacterial or fungal growth — "rotten egg" or "musty" smell)

• Heavy tramp oil buildup that skimming/vacuuming can't keep under control

• Foaming that won't stop even after adding defoamer

• Rust or corrosion appears on parts or machines

• Poor grinding performance (burning, poor finish, clogging wheels)

Step 1: Identify why it’s foaming

Foaming isn't random — it usually has one or more causes:

• Coolant is too thin (too much water, concentration too low)

• Wrong mixing method (adding water to coolant instead of coolant to water)

• High-pressure pumps / air entrainment (lots of agitation)

• Contamination (tramp oils, cleaners, incompatible additives)

• Coolant is old and breaking down

• Water hardness is too low (soft water increases foaming)

Step 2: Quick Fixes to Try First

Good question — and it’s important because improper coolant disposal can cause big legal, environmental, and cost problems.
Here’s a clear, correct way to handle used coolant disposal:

1. First: Understand the Law

• In the U.S., used metalworking fluid (coolant) is often considered industrial waste.

• It can become hazardous waste if:

  • It contains heavy metals (like lead, chromium, or cadmium) above limits.

  • It is contaminated with solvents or oils.

• If hazardous, you must follow strict EPA rules (and probably local/state rules too).

• If non-hazardous, you still cannot just dump it down a drain without permission.

2. Options to Dispose of Coolant Properly

The coolant you can use depends on many variables including but not limited to the machine, the application, the material being ground, filtration etc.

You may also have specific needs when grinding that only certain coolant can provide.

Here is a general summary.