Why Is Protective Coating Peeling from Factory Equipment? Malaysia
Meta Description: Discover why protective coatings peel from factory machinery, pipes and tanks, and learn how coating thickness, humidity and surface-temperature measurements support troubleshooting.
Protective coatings help shield factory machinery, pipes, tanks and steel structures from corrosion and environmental exposure.
When paint begins to peel, blister or separate from the metal, repainting the damaged area without identifying the cause may only provide a temporary solution.
Common causes include poor surface preparation, contamination, incorrect coating thickness, moisture, unsuitable application conditions and corrosion beneath the coating.
Common Causes of Coating Failure
The most common causes include:
Poor surface preparation
Oil, grease or dust contamination
Moisture on the surface
Condensation during application
Coating applied too thinly
Coating applied too thickly
Incorrect curing
Incompatible coating layers
Corrosion under the coating
Excessive heat or chemical exposure
1. Poor Surface Preparation
A coating needs a clean and suitably prepared surface.
Problems may occur when the surface contains:
Rust
Mill scale
Old loose paint
Dust
Salt
Welding residue
Product contamination
Inadequate surface profile
A new coating may adhere to the contamination rather than the base metal.
When the contamination separates, the coating peels away with it.
2. Oil and Grease Contamination
Machinery and production equipment may contain:
Lubricating oil
Hydraulic oil
Cutting fluid
Grease
Silicone
Release agent
Cleaning residue
Even a thin, difficult-to-see layer can affect adhesion.
The surface must be prepared using a cleaning method compatible with the coating system and substrate.
3. Dust on the Surface
Dust can remain after:
Grinding
Abrasive blasting
Sanding
Nearby construction
Production work
Surface cleaning
Painting over dust creates a weak layer between the coating and metal.
Inspect the surface immediately before application.
4. Moisture and Condensation
A metal surface may appear dry while its temperature is close to the air’s dew point.
Condensation may form during coating application because of:
High humidity
Rapid temperature changes
Cold metal
Rain
Night-time cooling
Air-conditioning
Steam or water nearby
Useful measurements include:
Air temperature
Relative humidity
Surface temperature
Dew point
A temperature-humidity meter and suitable surface-temperature probe can support these checks.
5. Coating Applied Too Thinly
Insufficient dry film thickness may result in:
Poor corrosion protection
Early rusting
Pinholes
Weak coverage
Shorter coating life
A coating thickness gauge provides non-destructive dry-film thickness measurements on suitable metal substrates.
6. Coating Applied Too Thickly
Excessive coating thickness can also create problems.
Possible effects include:
Slow curing
Solvent retention
Cracking
Wrinkling
Sagging
Poor intercoat adhesion
Material waste
More coating does not automatically mean better protection.
7. Incorrect Curing
A coating may fail to cure correctly because of:
Low or high temperature
Excessive humidity
Incorrect mixing ratio
Insufficient drying time
Poor ventilation
Wrong thinner
Coating applied too thickly
Application outside the recommended conditions
Follow the coating manufacturer’s application and curing instructions.
8. Incompatible Coating Layers
A new coating may react poorly with an existing layer.
Possible problems include:
Lifting
Wrinkling
Softening
Poor adhesion
Chemical reaction
Uneven curing
Before maintenance repainting, identify the original coating system and confirm compatibility.
9. Corrosion Under the Coating
Corrosion may continue beneath an apparently intact coating.
Possible signs include:
Blisters
Rust staining
Local swelling
Cracking
Peeling
Discolouration
Moisture around edges
The underlying metal condition must be assessed before repainting.
10. High Operating Temperature
A coating used outside its intended temperature range may:
Discolour
Harden
Crack
Soften
Lose adhesion
Degrade chemically
Use an infrared thermometer or thermal imaging camera to check actual equipment surface temperature during operation.
11. Chemical Exposure
Factory coatings may be exposed to:
Solvents
Acids
Alkalis
Cleaning chemicals
Oil
Process vapours
Salt
Wastewater
The selected coating must be compatible with the actual chemical and temperature conditions.
12. Mechanical Damage
Coatings may fail because of:
Impact
Abrasion
Vibration
Flexing
Product contact
Forklift damage
Tools
Repeated cleaning
The damage mechanism should be addressed before applying a new coating.
How to Use a Coating Thickness Gauge
Step 1: Identify the Substrate
Confirm whether the base metal is ferrous or non-ferrous.
Step 2: Verify the Instrument
Use the supplied reference plates and foils according to the manufacturer’s instructions.
Step 3: Select the Correct Mode
Use the appropriate ferrous or non-ferrous measurement method.
Step 4: Measure Several Locations
Include flat areas, edges, corners, weld zones and repaired areas.
Step 5: Record the Results
Document the equipment, location, individual readings and coating condition.
Coating Thickness Gauge Options
MTM Precision supplies:
Landtek CM-8820
Landtek CM-8828
Benetech GT1201
The suitable model depends on:
Substrate type
Coating thickness
Probe design
Surface curvature
Accessibility
Data requirements
Budget
Why One Reading Is Not Enough
Coating thickness may vary because of:
Spray angle
Applicator technique
Edges and corners
Surface roughness
Recoating
Overspray
Uneven drying
Complex equipment geometry
Take multiple readings across a defined inspection area.
Coating Gauge vs Ultrasonic Thickness Gauge
InstrumentWhat It MeasuresCoating thickness gaugePaint or coating above metalUltrasonic thickness gaugeRemaining thickness of the base material
For a corroded painted pipe, both instruments may be useful:
Coating gauge checks the protective layer
Ultrasonic gauge checks the remaining pipe wall
Using Temperature and Humidity Measurements
Before coating application, record:
Air temperature
Relative humidity
Surface temperature
Calculated dew point
Weather or room condition
A standard temperature-humidity meter may calculate dew point on suitable models.
If not, use the approved method required by the coating procedure.
Using Thermal Imaging
A thermal camera may help identify:
Hot machinery surfaces
Uneven operating temperature
Damaged insulation
Moisture-related temperature patterns
Areas affected by nearby heat sources
Thermal imaging does not directly measure coating adhesion or dry film thickness.
Basic Coating Failure Investigation
Step 1: Identify the Failure Pattern
Determine whether the problem involves peeling, blistering, cracking, rusting or discolouration.
Step 2: Check Where the Separation Occurred
Did the coating separate from the metal or between coating layers?
Step 3: Measure Coating Thickness
Take multiple readings on failed and unaffected areas.
Step 4: Review Application Conditions
Check temperature, humidity, surface temperature and curing time.
Step 5: Inspect Surface Preparation
Look for rust, contamination, old coating and insufficient surface profile.
Step 6: Check Operating Conditions
Review heat, chemicals, abrasion, vibration and moisture exposure.
Step 7: Assess Base-Metal Condition
Use an ultrasonic thickness gauge where remaining metal thickness is a concern.
Recommended Coating Investigation Tools
What to CheckRecommended InstrumentDry film thicknessCoating thickness gaugeRemaining metal thicknessUltrasonic thickness gaugeAir temperature and humidityTemperature-humidity meterSurface temperatureContact surface thermometerHot equipment patternsThermal imaging cameraRoutine surface-temperature checksInfrared thermometerLong-term environmental conditionsTemperature-humidity data logger
Common Coating Troubleshooting Mistakes
Avoid:
Repainting without identifying the cause
Measuring only one location
Ignoring surface contamination
Ignoring humidity and dew point
Assuming thicker coating is always better
Applying new coating over loose old paint
Ignoring coating compatibility
Using the wrong substrate mode
Confusing coating thickness with metal thickness
Measuring a wet or dirty surface
Ignoring chemical and temperature exposure
Recording readings without identifying the location
Coating Inspection Tools Supplier in Malaysia
MTM Precision supplies instruments for investigating coating peeling, insufficient paint thickness, corrosion protection, surface temperature and remaining metal thickness.
Our range includes Landtek CM-8820, Landtek CM-8828 and Benetech GT1201 coating thickness gauges, ultrasonic thickness gauges, temperature-humidity meters, thermal imaging cameras and Smart Sensor AR600E infrared thermometers.
Contact MTM Precision
MTM Precision Sdn. Bhd.
Showroom & Service Centre
No. 29-1 & 29-2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia
🌐 Website: www.mtmpre.com.my
📧 Email: mtmpre@yahoo.com
📱 WhatsApp: +6016-660 7346
31 Aug 2026
