What is Metal Spray?

Metal spray — often referred to as thermal spray coating — is a process where molten or semi-molten metal particles are propelled and deposited onto a substrate to rebuild or protect surfaces. In motor servicing, it is commonly applied to shafts, bearing housings, end bells, and rotor journals that have been worn, corroded, or scored.

Why Metal Spray Matters in Motor Overhaul

Industrial motors operate under heavy loads and harsh environments. Over time, key components experience wear and corrosion that degrade performance. Metal spray repairs restore dimensional accuracy and surface properties so components can return to service without expensive replacement.

• Restores shaft diameter: Rebuilds undersized or scored shafts to factory tolerances so bearings and couplings fit correctly.
• Prevents further corrosion: Adds a protective barrier against moisture, chemicals, and oxidation.
• Improves bearing fitment & alignment: Accurate restoration reduces vibration and premature bearing failure.
• Enhances surface hardness: Many spray materials increase wear resistance, extending component life.
• Reduces downtime and cost: Faster and less expensive than fabricating or sourcing replacement parts.

Typical Applications

Metal spray is widely used across heavy industries where motor uptime is critical:

• Power plants and generators
• Palm kernel shell (PKS) processing mills and palm oil facilities
• Cement, chemical and petrochemical plants
• Water treatment and pump stations
• Data centers and HVAC motor maintenance

What to Expect in a Professional Repair

When performed by experienced technicians, metal spray repairs follow a clear workflow:

1. Inspection and measurement of the worn component
2. Surface preparation (cleaning, grit blasting if required)
3. Metal spray application using the appropriate spray material
4. Machining to final dimension and tolerance
5. Polishing, balancing (if shaft/rotor), and final inspection

This ensures restored parts meet operational precision and dynamic balance — essential for high-speed motors.

Choosing the Right Spray Material

Selection depends on the application and environment. Common options include:

• Nickel-based alloys — good corrosion resistance and bond strength
• Chromium or chromium-based overlays — very high wear resistance
• Aluminum — lightweight and corrosion protection for certain environments
• Bronze/Copper — used where good bearing properties or electrical conductivity are required

Conclusion

Metal spray is more than a repair technique — it is a strategic maintenance step that restores precision, protects against future damage, and extends equipment life. For many plants and facilities, choosing metal spray repair over part replacement delivers faster turnaround and significantly lower lifecycle cost.