When an industrial coating starts peeling, blistering, cracking, wearing prematurely, or otherwise failing, changing the coating isn’t always the first—or right—solution.
The problem could originate with surface preparation. Application conditions may have changed. Equipment may no longer be operating consistently. The cure process may not fit production. Or the coating formulation may not match the substrate, manufacturing process, or environment in which the finished product is being used.
That’s why troubleshooting industrial coating failure starts with diagnosing the entire coating system.
Understanding what changed, where the failure occurs, and when it appears can help manufacturers identify the source of the problem before making costly changes to the wrong part of the process.
What Is Industrial Coating Failure?
An industrial coating failure occurs when a coating no longer performs one or more of the functions it was designed to provide.
Depending on the application, that may include premature loss of:
- Adhesion
- Corrosion protection
- Chemical resistance
- Moisture resistance
- Abrasion or wear resistance
- Weather or UV resistance
- Appearance
- Other required performance properties
Some failures appear during application or immediately after cure. Others don’t become visible until the coated product has been handled, assembled, shipped, or exposed to its operating environment.
When the failure occurs can provide an important clue about its cause.
What Are the Most Common Causes of Coating Failure?
Industrial coating failures commonly originate in one or more of these areas:
- Surface preparation
- Application environment
- Application process and equipment
- Cure conditions
- Coating selection or formulation
- Changes in the end-use environment
The challenge is that similar-looking defects can have different causes.
A blister, for example, doesn’t automatically tell you why the coating failed. The underlying cause still needs to be investigated.
1. Inadequate Surface Preparation
A coating needs a properly prepared substrate to achieve the intended adhesion and performance.
Oil, grease, dirt, rust, scale, moisture, release agents, and other contaminants can interfere with the bond between the coating and the surface. Some substrates may also require a particular surface profile, chemical pretreatment, or primer.
Problems related to surface preparation can include:
- Poor adhesion
- Peeling or delamination
- Blistering
- Cratering
- Improper wetting
- Uneven appearance
If a coating isn’t adhering properly, surface preparation should be one of the first parts of the process you investigate.
The question isn’t simply, “Was the part cleaned?”
It’s “Was this substrate prepared correctly for this coating system?”
2. Application Environment
A coating that performs well under controlled conditions may behave differently when the production environment changes.
Temperature, humidity, moisture, dust, ventilation, air quality, and other environmental variables can affect application, flow, evaporation, cure, adhesion, and finished appearance.
If a coating that previously performed consistently begins developing problems, ask whether anything in the application environment has changed.
For example:
- Has the temperature changed seasonally?
- Is humidity higher or lower?
- Has ventilation changed?
- Is contamination entering the coating area?
- Is moisture or condensation present?
- Has another manufacturing process changed nearby?
Before assuming the coating itself has changed, rule out changes in the environment around it.
3. Application Process or Equipment
Industrial coatings are developed around particular application methods and process conditions.
Spraying, dipping, brushing, rolling, and other application methods introduce different variables. Even within a spray process, performance can be affected by equipment settings, tip condition, pressure, viscosity, film thickness, distance, technique, and line speed.
Application-related problems can include:
- Runs and sags
- Orange peel
- Uneven film build
- Poor coverage
- Pinholes
- Inconsistent appearance
Equipment should be part of the investigation as well.
Spray tips wear. Lines become contaminated. Settings change. Production speeds increase. Operators may apply the coating differently.
If the same coating suddenly starts behaving differently, don’t overlook the equipment and process delivering it.
4. Cure Conditions Don’t Match the Coating or Production Process
A coating can apply correctly and still fail if it doesn’t cure as intended.
Cure problems may result from insufficient time, incorrect temperature, excessive film build, production changes, or a coating whose cure requirements no longer fit the manufacturing process.
For example, coated components that are stacked, packaged, or assembled before the coating has developed sufficient properties may stick together or become damaged.
If production speeds have increased but the coating’s cure requirements haven’t changed, the process and formulation may no longer be compatible.
Ask:
- Is the coating receiving the required cure time?
- Are cure temperatures controlled?
- Has production speed changed?
- Has film thickness changed?
- Are parts being handled sooner than before?
The solution could be a process adjustment, a formulation adjustment, or both.
5. The Coating Doesn’t Match the Application
Sometimes the substrate is properly prepared, the equipment is operating correctly, and the process is controlled—but the coating still isn’t meeting requirements.
That’s when coating selection and formulation need closer examination.
An industrial coating has to work in two environments:
the manufacturing process and the finished product’s operating environment.
A coating may provide excellent chemical resistance but cure too slowly for the production line. Another may move through production perfectly but lack the abrasion resistance needed after the product enters service.
The right coating needs to account for factors such as:
- Substrate
- Application method
- Film-build requirements
- Cure process
- Production speed
- Chemical exposure
- Moisture
- Temperature
- Abrasion and handling
- Outdoor exposure
- Required appearance
- Expected service life
If those requirements change, the coating may need to change with them.
6. The End-Use Environment Has Changed
Not every coating failure starts in the finishing line.
A finished component may be exposed to conditions that weren’t considered when the coating was originally selected.
Perhaps cleaning chemicals changed. Operating temperatures increased. The product moved from an indoor to an outdoor environment. Parts are being handled more frequently. Moisture exposure increased.
When investigating premature failure, compare the environment the coating was designed for with the conditions it is actually experiencing.
If those no longer match, the original coating may simply be under-engineered for the current application.
What Do Common Coating Defects Tell You?
The appearance of a defect can help narrow the investigation, but it shouldn’t be treated as a diagnosis by itself.
Blistering
Blistering appears as raised areas or bubbles in or beneath the coating film.
Potential factors to investigate include moisture, contamination, adhesion, application conditions, and environmental exposure.
Peeling or Delamination
Peeling or delamination occurs when the coating separates from the substrate or another coating layer.
Investigate surface preparation, contamination, adhesion, compatibility between coatings, and cure.
Orange Peel
Orange peel is an uneven surface texture resembling the skin of an orange.
Possible factors include viscosity, atomization, application technique, equipment settings, flow, and environmental conditions.
Runs and Sags
Runs and sags occur when the coating flows after application rather than remaining at the intended film build.
Film thickness, viscosity, application technique, temperature, and cure conditions may all contribute.
Pinholes
Pinholes are small openings in the coating film that may expose the underlying substrate.
Surface contamination, trapped air or solvent, application conditions, and film formation are among the factors worth investigating.
Chalking
Chalking is the formation of a powdery material on the coating surface as the film degrades.
If chalking occurs prematurely, evaluate the coating’s resistance to the actual environmental exposure.
Cracking or Checking
Cracks or small breaks within the coating film can indicate problems involving flexibility, film thickness, cure, aging, environmental exposure, or formulation.
The important point is that one defect can have several possible causes.
Use the defect to determine where to investigate—not to jump immediately to a solution.
How Do You Troubleshoot an Industrial Coating Failure?
A systematic investigation is usually more useful than changing multiple variables at once.
Start with these questions.
What Changed?
This is often the most important question.
Look for changes in:
- Substrate or substrate supplier
- Raw materials
- Pretreatment
- Application equipment
- Operators
- Line speed
- Film thickness
- Cure schedule
- Production environment
- Cleaning processes
- Coating batch or product
- End-use conditions
A process that worked consistently and suddenly stopped working usually has a variable worth finding.
Where Is the Failure Occurring?
Determine whether the problem affects:
- Every part
- One production line
- One shift
- One operator
- One substrate
- One batch
- Particular areas of the part
- Products exposed to a specific environment
Patterns can help narrow the possible cause.
When Does the Failure Appear?
Does the defect appear:
- During application?
- During cure?
- During handling or assembly?
- After packaging?
- After installation?
- Only after environmental or chemical exposure?
The timing can help separate production problems from end-use performance problems.
Is Film Thickness Correct?
More coating isn’t automatically better.
Excessive film build can affect flow, cure, appearance, and adhesion. Insufficient film build may prevent the coating from delivering its intended protection or appearance.
Confirm that the actual film thickness matches the coating and application requirements.
Does the Coating Still Match the Process?
Manufacturing processes evolve.
A coating selected years ago may still be used even though the substrate, line speed, cure schedule, equipment, or performance requirements have changed.
Sometimes the coating hasn’t failed unexpectedly.
The application has changed around it.
When Does a Coating Need to Be Reformulated?
Not every coating problem requires a custom formulation.
If the problem is a contaminated substrate, worn spray tip, incorrect film thickness, or uncontrolled cure process, changing the chemistry may only mask the real issue.
Formulation should become part of the conversation when the coating itself no longer fits the requirements.
That may include situations where:
- Cure time doesn’t fit production speed
- Adhesion remains inconsistent despite controlled surface preparation
- The coating doesn’t tolerate the actual operating environment
- Required chemical, abrasion, heat, moisture, or weather resistance has changed
- Application characteristics don’t fit the equipment or process
- A substrate or manufacturing process has changed
- Existing products require repeated workarounds to perform acceptably
- Batch-to-batch or performance problems continue after process variables have been investigated
The goal isn’t to custom-formulate everything.
It’s to determine whether chemistry is actually the variable that needs to change.
How Can Manufacturers Reduce the Risk of Coating Failure?
Preventing coating problems requires treating the coating as part of the manufacturing system rather than an isolated material.
Maintain repeatable surface-preparation procedures. Audit application equipment and process settings. Track environmental and cure conditions. Listen to operators when application behavior changes. And reevaluate the coating whenever the substrate, process, or performance requirements change.
Most importantly, document what works.
Consistent inputs and controlled processes make it easier to achieve repeatable coating performance—and much easier to identify the source when something goes wrong.
Is the Problem the Coating or the Process?
You shouldn’t have to guess.
When an industrial coating is failing, the first step is to understand the substrate, surface preparation, application process, equipment, cure conditions, operating environment, and coating requirements.
Aexcel works with manufacturers to evaluate underperforming coating systems and identify where the problem is occurring. When chemistry is part of the issue, manufacturers can work directly with Aexcel’s lab and formulation team to test adjustments, evaluate performance, and determine a path forward.
