CAUSES OF FAILURE
The majority of paint and coating-related failures can be attributed to six primary causes. These causes are as follows.
1. Improper surface preparation
May include improper cleaning, chemical pretreatment or surface roughening.
2. Improper coating selection
Not suitable for the intended service environment, or not compatible with the substrate.
3. Improper application
Either shop-applied or field applied coatings, and occurs when the required specifications or parameters for the application are not met.
4. MECHANICAL DAMAGE
Results from improper handling of the painted or coated substrate, resulting in a breach in the paint or coating.
5. Lack of protection against water and aqueous systems
Serious problem with aqueous systems containing corrosive compounds such as chlorides.
6. Improper drying, curing and over coating times
Lack of conformance to the required specifications or parameters.
Types of Failures
Formulation-Related Failures
These types of failures are related to the formulation of the coating itself. If the coating system that is selected by the engineer is formulated inadequately, the coating will most likely fail regardless of all efforts made in an optimal application.
These formulation-related failures occur as a result of the ingredients used and their formulation in the paint or coating. These ingredients include the resins used, the pigments used, as well as the solvent formulation.
Organic Coating Failure Types
Chalking
CHECKING
CRACKING
Wrinkling
Discoloration
Erosion
ALLIGATORING
MUD CRACK
Biological failure
Zinc Coating Failure Types
Checking
pinpoint rusting
Mud Cracking
SUBSTRATE-RELATED FAILURES
A substantial percentage of paint and coating failures are related to the substrate to be coated and its proper preparation prior to coating. To eliminate this class of paint and coating failure, it is imperative that the painters and coating applicators take great care in following specified methods of surface preparation.
Substrate-Related Failure Types & Causes
Previously used steel
Retention of minute amounts of corrosion product even after abrasive blast
galvanized or metallic zinc surface
Formation of zinc salts under coating
aluminum
Smooth surface. No adhesion
copper
Smooth surface. No adhesion
Wood
Expansion and contraction of wood in varying temperatures and humidity
Concrete
Chemical reactivity, moisture content and porosity of concrete
Physical Defect-Related Failures
Many of these physical defect-related failure types overlap with the formulation-related failure and substrate-related failure types discussed above. However, these physical defect types and their nomenclature as discussed here are traditionally considered by the paint and coatings industry, and they merit a separate category.
Physical defect-related failure types
Blisters
Dirt
Bubbles & Craters
Color mismatch
Fisheyes
Gloss Variations
Mottle
Orange Peel
Runs, sags, & Curtains
Paint adhesion loss
Soft paint films
Solvent wash
SOLVENT POPPING, BOILING, & PINHOLES
We are Here to Help!
We respond to all customers promptly by sending a technical proposal to address testing, investigation and the proposal costs. If we need more information, our engineers will contact you. We respond to all customers promptly by sending a technical proposal to address testing, investigation and the proposal costs. If we need more information, our engineers will contact you. Whether you are a large corporation or a small enterprise, we will provide you with the attention you need and deserve. In so doing, we hope to work with you for many years to come.
Please call Dr. Zee at 412-952-9441 or the office at 412-788-1263 and let us know how we can assist you in your investigation. Alternatively, you can send your request to info@matergenics.com.
Looking forward to hearing from you!