Why Water Matters More Than You Think in Metalworking Applications
Coolant performance plays a pivotal role in the efficiency, longevity and reliability of machinery used in metalworking operations. Yet, one key variable is often overlooked when it comes to maintaining coolants: water quality. Given that water-dilutable coolants are typically composed of 90–95% water, even minor inconsistencies in water chemistry can significantly affect coolant stability, machinery health and system effectiveness.
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How Water Quality Affects Coolant Effectiveness
Water quality can either enhance or undermine the performance of your coolant. The chemical balance of water you use during preparation and replenishment directly determines how well your coolant emulsifies, protects machine surfaces and prevents bacterial growth.
When water is too hard, too soft, acidic, alkaline or filled with contaminants, it disrupts this chemical balance, resulting in several issues.
Common Problems Caused by Poor Water Quality
Water Hardness Issues
• Example: A facility uses hard water containing excessive calcium and magnesium ions. This leads to scum, residue and deposits within coolant delivery systems.
• Impact: Scale buildup clogs pipes and nozzles, reducing coolant flow and heat dissipation. Over time, this causes overheating, increased tool wear and higher coolant consumption.
Imbalanced pH Levels
• Example: Water with a pH level below 6.5 may destabilize coolant emulsions, or trigger separation of oil and water phases. Alternatively, water with a pH higher than 7.5 may cause persistent residue formation.
• Impact: Low “system” pH levels can increase corrosion – water, itself, will ALWAYS corrode – and higher pH fluid may not cause any issues.
◦ System pH levels above 10 can cause irritation.
Contaminant Intrusion
• Example: Water drawn from a corroded system contains chlorides and bacteria and exhibits high conductivity. Elevated conductivity indicates the presence of chlorides and other dissolved ions, which accelerate machine part corrosion. Additionally, water hardness compounds the issue by contributing to scale buildup, while microbial contaminants promote bacterial growth in the sump.
• Impact: Corrosion pits metallic surfaces, weakening machine components. Simultaneously, microbial activity degrades coolant performance, emits foul odors and shortens sump life.
Clearly, understanding and controlling water quality is essential to avoid these costly scenarios.
Best Practices for Safeguarding Coolant and Machinery
Routine water testing and preventive measures can protect your operation from the challenges posed by poor water quality. Below are actionable steps to maintain optimal coolant performance and extend machinery life.
1. Test Your Water Regularly
Water testing ensures you can identify changes or issues in quality before they become problematic. Here’s how to do it effectively:
• Use simple test strips to measure hardness, pH and contaminants such as chlorides and sulfates.
• Send periodic samples to a lab for comprehensive water analysis, especially if your facility experiences variable water sources.
• Incorporate automated water testing systems for consistent monitoring of water properties.
Tip: If you’re not sure where to start, consult an AMSOIL Industrial Application Engineer for recommendations tailored to your facility.
2. Use Treated or Deionized Water
For facilities subject to challenging water conditions:
• Invest in reverse osmosis (RO) or deionized (DI) systems to remove excessive cations, anions and microorganisms.
• RO systems balance operational cost with effectiveness, filtering out hardness and contaminants.
• DI water, although pricier, is ideal for critical applications requiring ultra-pure water.
Caution: Avoid using softened water, as it replaces hardness ions with chlorides, potentially exacerbating corrosion problems and increasing foaming.
3. Follow Proper Mixing Procedures
Incorrectly mixing coolant concentrate with water can ruin its chemical stability. Best practices include:
• Always add coolant concentrate to water — never the reverse — to ensure proper emulsification.
• Use proportioning equipment to maintain consistent and accurate mixing ratios, minimizing human error.
This ensures your coolant achieves an even composition, enhancing its protective and lubricating properties.
4. Monitor and Remove Contaminants
To combat suspended solids, microorganisms and chemical impurities:
• Include filtration systems to eliminate visible particles like rust or sand.
• Keep chloride levels below 200 ppm to limit corrosion potential. If levels exceed [300 ppm], consider water treatment interventions or sump replacement.
• Test for bacterial contamination. Microbial levels exceeding 1,000 CFU/mL require biocide additions or improved sanitation practices.
5. Develop a Maintenance Schedule
Even the best water systems require consistent attention to function as intended. Develop a plan to:
• Check water quality weekly or bi-weekly.
• Conduct quarterly evaluations of sump conditions, coolant stability and microbial activity.
• Perform periodic maintenance on filtration, RO or DI systems.
The Payoff of Routine Water Testing
By prioritizing routine water testing and implementing best practices, you can:
✓ Extend coolant life
✓ Reduce downtime and operating costs
✓ Improve tool performance and longevity
✓ Minimize environmental waste
✓ Ensure safer working conditions for operators
Neglecting water quality introduces hidden risks that accumulate over time, undermining your facility’s efficiency and increasing operational expenses. Conversely, proactive management leads to longer sump life, more reliable machinery and cost savings.
Take Action Today
Don’t leave your coolant or machinery to chance. Start testing your water quality today and see the immediate impact on your operation’s performance.
FREE DOWNLOAD >>> Routine Water Testing for Coolant Performance
For detailed guidance or to schedule a water analysis consultation, connect with an AMSOIL Industrial Application Engineer today.