Steel Coatings Articles

Greatest Hits: The Case of the Yellowed Epoxy

This feature is part of a special anniversary series in 2017 in which CoatingsPro reflects on and updates the magazine’s most-read digital stories. We’re giving a new twist on the original article with a fun quiz! Read the original here and then take the test at the end.  To read the other articles in the Greatest Hits series, click here 


The professional coatings industry is like just about anything else in life: We have a tendency to clearly remember the good times and the bad, the highs and the lows, yet we lose sight and focus on the average and the ordinary. As with any function in the construction industry, painting contractors are in the business to earn a fair and equitable profit while avoiding risk as much as possible. As any painting contractor will tell you, we have all had failures to one extent or another, and we all clearly remember the costs associated with our most expensive mishaps.

Recently, I was involved as the third party chief inspector and consultant on a major project that involved the removal of lead-based paint from structural steel (columns, purlins, girders, and cross bracing) and recoating with a zinc-rich aromatic urethane primer and two coats of polyamidoamine epoxy of contrasting colors: a gray intermediate coat and white topcoat. The project involved replacing a 10-acre (40,469 m²) roof comprised of approximately 33,000 concrete roof slabs measuring 30 inches (76 cm) wide by 60 inches (152 cm) long. It also involved replacing structural steel members that had been identified as “integrity lost” prior to installing the new concrete panels and subsequent roofing system.

Since the abrasive blasting of the structural members would severely damage the new concrete roof slabs, the blasting and painting would take place prior to the replacement of the roof. When the old slabs were removed, this permitted the replacement of structural members with new steel, which had been shop blasted and primed only. Once in place, the new steel received the two coats — the intermediate and top coats — by brush and roller. The site was not conducive for spray application as there were many automobiles and adjacent buildings in close proximity, and, therefore, overspray was a major concern. The installation of the replacement structural steel was completely off schedule for various reasons, and sections of the roof remained open for periods ranging from two weeks to two months.

Not Mellow Yellow

As any painting contractor knows, when you follow in the path of steel workers you are going to encounter a vast array of coating damage caused by welding, torch cutting, grinding, hammering, abuse, and negligence. The old adage of steel workers “beating it to fit” and the coating applicators “painting it to match” never rang as true as it did on this project. Added to this was the damage caused to the tops of the purlins by the installation of the concrete slabs. Subsequently, repairing and touching up the coating system became an all-consuming endeavor for the painting contractor. They had more than six full-time employees dedicated to touch up alone, which lasted for more than one year.

When it came time for the final inspections of visual appearance and dry film thickness, everyone on the project was amazed. The structural steel looked like a spotted cheetah! When the roof sections were off during the steel replacement, the epoxy had been exposed to sunlight for extended periods of time. The touch ups and repairs to the existing steel and the top coating of the new steel were ongoing and continuous, so the sunlight exposure time of the applied epoxy varied widely. Since the topcoat was white, we now had varying degrees of serious yellowing spots and major gloss range issues.

As usual, the owner, general contractor, painting contractor, coating manufacturer, and yours truly began what seemed to be an endless effort to determine the effect of the color and gloss, which included various tests to determine the functionality of the applied coating system.

We completed and evaluated the tests with the final determination indicating the coatings were mixed, applied, and cured properly and that the coatings performance would not be inhibited by the color and gloss issues. Nonetheless, the owner was not impressed by these efforts and wanted a monolithic and homogeneous appearance.

Throughout the testing and negotiations with the owner, the painting contractor did nothing to correct the appearance issues as they focused on other aspects and obligations of the project. Meanwhile, other trades continued to work on their projects, including the placement of temporary scaffolding supplied, which had been erected and maintained in sections of 1.25 acres (5,059 m²). These sections were covered in ¾-inch (2 cm) plywood sheathing for containment support and ease of access, and the scaffolding would need to be removed and reinstalled to another area of the project. The date for the dismantling was approaching quickly. But once it was gone, the painters couldn’t come back into that area to fix the cheetah spots.

That’s when the inevitable happened: the screaming and yelling started!

Hiding Spots

Generally speaking, the various personnel and trades on a project of this size and duration get along, and friendships commonly develop. However, when money and reputation are put on the line, the situation can become pretty heated. Frustrations can build, which often erupt in arguments. That’s exactly what happened on this job.

The general contractor’s bottom line was that the scaffolding replacement could not be delayed and the painting contractor had to make a decision regarding the yellow spots. They could apply an additional coverage coat of paint to the entire structure or they would be fired from the project. As I sat in the office trailer with the painting contractor that afternoon, I will never forget the candid conversation we had and the look on his face as he considered his options. Realizing how much money was on the line, I had a deep and profound empathy for him, yet I knew the owner had a valid and uncompromising position.

The next day I stood in awe as a literal battalion of men walked through the gate accompanied by a truck full of supplies and materials to commence with the brush and roller application of the topcoat. They had decided to cover the entire project with another coat to cover the yellowed epoxy spots.

As any coating inspector will tell you, one person can only observe, record, and report on the activities of a limited number of men, and for the next two weeks I was literally stretched to the limit. In the end, the project was completed as scheduled, and measures were undertaken to avoid the exposure problem on the remaining phases of the project.

I have been involved in numerous projects since then; and although this event went into my professional history book as a low point, it was handled with the respect and attention that it deserved.

Test your knowledge of this article with a fun quiz:

About the Author:

Craig Campbell is the managing partner of Paint Inspection Services, Inc., a highly specialized and diversified company serving both public and private clients throughout North America. He has over 27 years of increasing experience and responsibility in the professional coatings industry in varying degrees. Beginning with the U.S. Army Corps of Engineers and continuing into private practice, his involvement includes functions in sales and marketing, field and shop production, operations management, quality control and assurance, shop and field surface preparation, and coating application inspections. His more recent areas of expertise include forensic coating failure analysis, expert witness, litigation support, executive management, and professional development. For more information, contact: Paint Inspection Services, Inc., (513) 237-7839,
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