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Multiple Planes of Adhesion: What You Need to Know When Selecting a Paint or Coating System

WEDNESDAY, MAY 20, 2020

By Warren Brand


First, let me apologize in advance for the length and complexity of this blog. In truth, I’ve been devoting my writing mojo (what little of it there is) to a book, which I expect to release sometime over the summer or early fall. It will be on the fundamentals of decision-making and I will let you know when it’s out. I humbly believe it will be a good read, and, with a little luck, provide some value. The working title is The Alternative Response Method.

But back to this blog which, I suggest, is really important. While we will be talking, technically, about the risks associated with using multiple-coat paint systems, it is also a blog about being intellectually suspicious whenever someone is trying to sell you something. And, further, the more complex the purchase, often, the more difficult it is to make an informed decision.

Why? Because where there’s confusion, there’s profit. This is not my opinion; this is fact. From an economic perspective, we have commodities, such as rice, gasoline, corn, flour and things that people purchase based almost entirely on price. Once goods and services can be differentiated, companies can charge more based on the notion that one item is purportedly better than another.

Images courtesy of the author

While we will be talking, technically, about the risks associated with using multiple-coat paint systems, it is also a blog about being intellectually suspicious whenever someone is trying to sell you something.

The Romans knew this and came up with the phrase, “caveat emptor,” which means “buyer beware.” Producers of complex goods and services know this as well, which is why warranties and guarantees exist: to protect the uneducated buyer.

Protecting the Buyer

Buying a banana (a commodity), for example, is a whole lot easier than figuring out all of the features and nuances you want in your cell phone or car, non-commodities. That’s why you get fairly substantial warranties with these items, but, sadly, not with your banana.

This brings us face-to-face with the paint and coatings industry—specifically paint and coatings manufacturers and, to a lesser-extent, contractors as well as most architectural and engineering firms.

I remember just a few years ago working on a massive failure of a coating system on a new concrete drainage running throughout a facility. I read the email exchange that lead to the coating specification, which read little better than this:

Owner: “Hey, we have some concrete we need to protect. What do you recommend?”

Paint supplier: “Hey, technical says this stuff should work.”

Owner: “Great. Thanks.”

This highlights the entire problem within our industry. The owner is uneducated as to the complexities of the issue and relies on the seller to provide the right product.

To be clear, this is not the owner’s fault. No more than it is yours or mine when we go buy a car, phone, microwave or any other complex purchase. Unless we’re engineers familiar with every component of the item, we have to trust the seller. The seller understands this and, therefore, puts their mark of integrity on their product in the form of a warranty.

Do you think the owner in this case of the concrete coating failure would have spent a half a million dollars on pumps, valves or vehicles without any type of warranty? Of course not.

To be fair, some material suppliers do provide warrantees, typically a year. However, when I owned an industrial coatings company, we often offered 10-year, non-prorated guarantees, and we stood by them. To the best of my knowledge, other than my old company, those types of assurances don’t typically exist today.

Between a Sledgehammer and a Hard Place

I remember about 20 years ago, we had lined the inside of a large concrete wastewater treatment tank at a chemical facility that was treating runoff from a gypsum field. In one of the concrete tanks, the gypsum would precipitate out of the solution and build up on the walls. If not cleaned, the gypsum would form rock-hard sheets sometimes up to an inch thick all over the interior walls.

I was surprised when I got a call a few years after coating it. The customer, George, who had become a good technical friend and resource, said the coating had come off in a few areas. I was surprised and told him I would come out the following week personally to make repairs.

The tank was about 30 feet tall and roughly 10 feet wide on each side. I climbed down the ladder and noticed an odd pattern to the damage. They were isolated and looked kind of like something had impacted the coating.

“George?” I yelled up from the tank bottom. “How do your guys get the gypsum off the walls?”

He yelled back, “Well, Warren, if we let it go too long it gets thick and hard, and we have to use sledgehammers.”

Once he realized what he said, we both started laughing. Finally, George said, “I guess we have to find a different way to remove the buildup.”

The damage to the coating was due to an engineer smashing it repeatedly with a sledgehammer. George offered to pay me for the repairs, since beating on the coating system with a sledgehammer was not covered in our warranty, but I declined. I was already there, and George always had donuts and coffee and was a pleasure to work with.

To be fair, some material suppliers do provide warrantees, typically a year. However, when I owned an industrial coatings company, we often offered 10-year, non-prorated guarantees, and we stood by them. To the best of my knowledge, other than my old company, those types of assurances don’t typically exist today.

So, why don’t paint suppliers provide better warranties, particularly when millions of dollars are at stake? For a number of reasons.

  1. Most failures are due to application error. And, to be fair, manufacturers should not have to pay for faulty application work.
  2. The market has not demanded it. (I’m hoping my blogs over time will, in some small way, change that.)
  3. Paint suppliers can make a ton more money when there is a failure. How? They get to blame the coating applicator and sell more paint.

Is this an exaggeration? Ask around. I hope people respond and convince me otherwise.

Before we start our deep, technical dive, ask yourself this: What kind of warranty comes with the most recent paint or coatings project you’ve been involved with, and does your firm enforce paint and coatings warranties?

From my experience, warranties from paint suppliers are typically a year and have so many caveats and exculpatory clauses that they are nearly worthless. And, further, again speaking from experience, rarely enforced.

In fact, one of the largest paint companies on the planet provides no warranty at all for internal, industrial tank lining.

Back to Multiple Planes of Adhesion

For the purpose of the remainder of the blog, we’re going to use interior tank lining as our exemplar. Why? Because interior tank lining (one of CCG’s specialties) remains as some of the most complex coating projects on the planet, particularly as you get into tanks that hold acids, bases, potable and edible materials, thermal shock, solvents and varying temperatures, and concentrations and formulas. And then there are also issues with the cold-wall effect, oil-canning and more.

When you apply a single coat of paint to the surface of an abrasively blasted tank, you have one plane of adhesion.

Diagram 1:

 

When you apply two coats, you have two planes.

Diagram 2:

 

And, of course, three coats, three planes, and so on.

Diagram 3:

 

Why is this important? Because it touches back to the beginning of my blog and why coating companies don’t offer warranties.

First, it’s a commonly accepted fact that most coatings failures are due to application error—I’ve heard anywhere from 70-95%.

And that number, that risk, applies every single time you add a coat of paint.

The more coats of paint, the greater the likelihood of a failure. I’m sure there’s a math formula to represent this (I’m not that bright) but I’m hoping this is intuitive and obvious.

Also, the greater the number of coats, in general, the more the job costs. Why? Well, the contractor has a labor cost associated with the application. One coat, one labor rate associated with that application. Two coats, and the labor rate for the application doubles.

And the coatings company typically makes more as well, as they’re selling more paint, and there’s wastage every time you spray a coat.

The takeaway?

  1. Make sure you completely understand what you’re purchasing. Do your due diligence: ask for references and call the references.
  2. Insist on a warranty in writing from the coating manufacturer and applicator, if possible.
  3. All things being equal, single-coat systems are better than multi-coat systems.

ABOUT THE BLOGGER

Warren Brand

Warren Brand’s coatings career has ranged from entry-level field painting to the presidency of two successful companies. Over nearly three decades, he has project-managed thousands of coating installations and developed specs for thousands of paint and coating applications. NACE Level 3 and SSPC PCS certified, Brand, an MBA and martial-arts instructor, now heads Chicago Corrosion Group, a leading coatings consultancy. Contact Warren.

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Tagged categories: Coating Materials; Consultants; NACE; Protective Coating Specialist (PCS); Protective coatings; Specification writing; SSPC; Adhesion; Asia Pacific; Coating Application; Coatings systems; EMEA (Europe, Middle East and Africa); Latin America; North America

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