2. Coating Defects and Failures
Presented by: Sarah Olthof

3. Topics Consequences of coating failure
Role of coatings inspector in failure avoidance
Common coating failures and defects

4. Scope
This webinar describes the consequences of coating failures, field and laboratory investigative processes undertaken to diagnose coating failures, and reviews common coating defects and failures.

5. Learning Outcomes
At the end of this unit, the student will be able to:
Recognize the consequences of coating failures
Describe the coating inspector’s role in preventing failures
Identify common coating failures and defects seen in the field

6. Protective Coatings Principal material used for corrosion protection
All coatings will breakdown over time
Service life can be extended by performing maintenance painting once deterioration is identified

7. Premature Coating Failure
Failures that occur before the anticipated service life ends can be caused by:
Improper surface preparation
Improper coating application procedures
Improper coating system selection
Improper formulation
Poor quality raw materials

8. Once Premature Failure Occurs…
The investigation begins…….
What was the cause of the premature coating failure?
What party was responsible for the failure?
What level of repair is required to ensure corrosion protection and integrity of the structure is acceptable?

9. Consequences of Coating Failures
Financial impacts
Litigation
Substrate repair or replacement
Costly rework and downtime

10. Substrate Repair or Replacement
When a failure occurs, the substrate is exposed to the environment until the defect is detected
Unprotected substrate is susceptible to corrosion and possible section loss
Integrity of structure could be compromised if coating failure is not detected for an extended period of time
Cost to repair substrate adds to the cost of the coating failure

11. Rework and Downtime
Remobilization, surface preparation, coating application, and inspection of the repair or rework can be time consuming and costly.
Hard to determine extent of rework needed.
Does the failure indicate total removal?
Can we get away with a spot repair?

12. Role of a Coating Inspector
The inspector can play a key role in helping to prevent premature coating failure.
Qualified inspection personnel can significantly reduce the opportunity for failure

13. Identification of a Non-Conformance
The inspector:
Identifies deficiencies as they arise
Will work with contractor for reaction plan once non-conformance is identified

14. Common Coating Defects and Failures

15. Delamination
Results from loss of adhesion between the substrate and coating OR between coats.

16. Delamination Common Causes Remediation Poor surface preparation
Intercoat cleanliness
Exceeding overcoating times
Incompatibility of topcoat and primer
Remediation
Area with poor adhesion must be completely removed and the cause should be evaluated before recoating.

17. Blistering
Coating lifting from the underlying substrate

18. Blistering Common Causes Remediation Contamination on the substrate
Oils and greases
Soluble Salts (osmotic blistering)
Solvent entrapment
Remediation
Ensure correct surface preparation and application
Soluble salt testing

19. Blush
Haze or oily residue on the surface of a coating

20. Blush Common Causes Remediation
High humidity or cold temperatures during application
Curing stages of an epoxy
Intensified by cool temperatures and increased coating thickness
Remediation
Blush will effect adhesion of topcoat
If blush is detected (not easy to detect) it is best practice to consult with product manufacturer on removal tactics

21. Sags/Runs
Downward movement of paint soon after application on vertical surfaces

22. Sags/Runs Common Causes Remediation Over application
Excessive thinning
Poor workmanship
Remediation
While wet, sags/runs should be smoothed with a paint brush
If dry, abrade, clean, and apply spot coat

23. Orange Peel
Pocked appearance; surface of paint film resembles the skin of an orange

24. Orange Peel Common Causes Remediation Poor application techniques
Incorrect solvent blend
Remediation
Abrade
Clean
Recoat

25. Pinholes
Formation of tiny holes in wet paint film during application and drying due to air/gas bubbles, which burst. The bursting bubbles form small craters or holes, which fail to coalesce before the film dries.

26. Pinholes Common Causes Remediation Solvent or air entrapment
Incorrect spray application
Incorrect solvent blend
Remediation
Abrade
Clean
Recoat

27. Holidays Similar to pinholes (used interchangeably)
Described as skips or misses in the coating system
Checked with holiday detector (right)

28. Holidays Common Causes Remediation
Difficult application due to equipment access
Poor workmanship
Remediation
Abrade
Clean
Recoat

29. Fisheyes
Small crater-like openings that form during application or shortly after

30. Fisheyes Common Causes Remediation Poor surface preparation
Contamination
Use of a thinner instead of solvent cleaner
Remediation
Abrade
Clean
Solvent cleaning
Recoat

31. Wrinkling
Wavy lines that appear in the paint film during different stages of coating application

32. Wrinkling Common Causes Remediation Excessive application of paint
Actual temperatures exceeding or going below application range
Overcoating before previous coat has sufficiently hardened
Remediation
Abrade
Clean
Recoat

33. Dry Spray
A rough or uneven finish in the paint film, were particles are not fluid and flowing together

34. Dry Spray Common Causes Remediation Improper application technique
Actual temperatures exceeding application range
Remediation
Ensure proper distance of the spray gun to the substrate is being achieved

35. Summary
There are many reasons why coatings may fail. The inspector investigates and identifies the cause of coating failure so that it can be remediated

36. QUESTIONS???