Poor Surface Preparation vs. Paint Adhesion
Question: I am a long time reader and first time writer.
I am a long time reader and first time writer. I am wondering if there has ever been a study of what causes the bulk of paint adhesion failures.
We are a small coatings manufacturer of architectural and industrial finishes, and we get customer complaints on specific products/batch numbers where the end user has experienced an adhesion failure. We analyze the batch in question and perform field testing of the batch on properly prepared substrates. 100 % of the time, we can not duplicate what the customer is seeing. Has there ever been any study that can attribute a percentage of the adhesion failures and cause? R. M.
As a long time reader, you probably saw my statement, “The greatest single cause of paint adhesion failure is poor surface preparation,” once or twice in Painting Clinic. I didn’t invent this statement. It probably goes back to paint consultants to the cave dwellers who decorated their walls with pigments ground in egg whites.
I am not aware of any published study that can attribute a percentage of adhesion failures to any cause. However a couple years ago, I did a non-scientific study of this problem. I found that, over the past 25 years, 40% of the questions published in my column were related to adhesion problems resulting from poor surface preparation.
However, I feel the percentage is much higher. Paint suppliers make good products designed to adhere to properly prepared surfaces. On the other hand, many product manufacturers pay little attention to their painting operations until they have problems. Painting is often done in the back of the plant where poor housekeeping is the rule. Paint inventories are often not rotated and old paint is applied. Poor application techniques are used. All of the aforementioned could contribute to paint adhesion failures.
Painting is the last step in the manufacturing process. I’ve attended product development meetings where the last thing said was, “Oh, and I guess we have to paint it....” I used to sit in these meetings wondering how I got into this business. I could have been a concert pianist or a ping pong champion.
Types of phosphate conversion coatings, how to apply them, and their specific functions.
An overview of spraying, dipping, flow coating, and everything in between.
A review of available test methods, common applications and innovative instrumentation...