To “B” Or Not To “B”

By Phil Fouche

I love epoxies. It’s public knowledge and my wife knows it. They work well in all kinds of situations:  above water, beside water, underwater!  They are easy to use and to apply by spray, brush, or roller.  They are tough and have good abrasive-, heat-, and chemical-resistance.  Of course, they do chalk when exposed to ultra-violet light.  However, I still love epoxies.

As a contractor, I have sprayed thousands of units of epoxy. As a supplier, I have sold pallet after pallet. I talked my wife into helping me put a three-coat epoxy system on my garage floor at home and now she loves epoxies!

Everyone that I’ve seen use epoxies seems to begin a love affair with them, too. But a true love affair takes two parts and so does an epoxy. And that begins our story.

I have a good customer, Bill, who is the maintenance foreman for a well known manufacturer of household cleaning machines manufactured in an aluminum molding plant. Once every couple of years the maintenance crew will clean the floor and install a two-coat epoxy system to protect the concrete from molten aluminum damage.  They prepare the floor by washing, scraping, and scarifying the surface in order to place the two-coat epoxy system.

Bill called and placed an order for epoxy to be delivered prior to the weekend of the coating installation. “Bill, I will come up and check everything out before you start that floor job,” I said.  “No need, Phil.  I have it all worked out and under control.  As a matter of fact, it is a plant shut-down and I have a funeral to go to. But all of my personnel know how to do the job.”  I offered to help him go over details of the job, but he refused and said not to worry.  I did not think about the conversation regarding the epoxy floor until the following Monday.


Working Knowledge of the Alphabet

Mid-morning on Monday the phone rang and it was Jim, Bill’s lead man, who was looking after the epoxy job in Bill’s absence.  “Jim, how did the job go on the epoxy floor?” I asked.  “Well, so far so good!  We got the floor cleaned and got one coat of the Part A down.  So, Phil, do we just roll the Part B over the Part A?  It seems as though this is going to get really messy when we walk on the Part A to apply the Part B.”

I couldn’t believe what I was hearing!  (But I could. This happens more times than you would think.)  

“Jim, let me correct your first statement.  So far, not so good.  I shipped the product data sheet that explains how the epoxy is mixed.  You must mix Part ‘A’ and Part ‘B’ together prior to application.  Did you take a look at that?”

“Naw, we just jumped in there and began rolling on the Part A because ‘A’ comes before ‘B’ in the alphabet.”  

“Yes, it does Jim. Yes it does.”

It Takes Two, Baby, To Make A Floor Come True

Epoxies cure by chemical reaction called polymerization. Reacting a resin Part A with a converter Part B causes a monomer to cross-link and make a polymer.  A monomer is like a single link of chain. After the reaction, you have a linked piece of chain -- the polymer.

Part A must be thoroughly agitated separately from Part B. Then, normally, the B is poured into the A which must be mechanically agitated by a power mixer. Generally -- with the exception of most 100% solids epoxies -- there is a required induction, dwell, or sweat-in time which allows for the chemical reaction to take place correctly.  The reason you cannot roll the B converter on top of the A resin is that they have to be properly mixed/agitated together so that the mass of the Part A and Part B solution will be insulated to the outside environment and allow heat to be retained during the chemical reaction. This in turn will create a better, more complete cross-linking of the monomers to become polymers.  An example of this type of reaction is the fact that there is more energy in a boiling pot than there is in an ice cube.

Let’s look at the ratio between Part A and Part B.  There are many ratios: one to one; two to one; three to one; and four to one.  There is even a “19 to one” in coal tar epoxy.  These ratios are a Part A resin to a Part B converter and are defined in the product data sheet of the particular products.  

Besides surface preparation and solvent entrapment, improper mixing and thinning is the greatest cause of paint failures. (You can put thinning into the same category as solvent entrapment.)

The point of all of this is to read the manufacturer’s product data sheet.  It is there for a reason.  Mixing and thinning, ratios, wet and dry film thickness are all crucial elements -- and all addressed in the manufacturer’s product data sheet.  These products are engineered to work a certain way if, and only if, they are mixed and applied properly.

Scraping By

Back to our problem on the floor…

“Phil, what are we going to do now?  It looks like Part A will dry.”

“Yes, Jim it will dry, but not cure.  However, it will never have the full hardness, or abrasion-, chemical-, and heat-resistance that it was designed for.”

“How can we remove the Part A?” Jim asked.

“Get out the scrapers and begin to scrape up the resin,” I said.

They got the mess cleaned up and redid the surface preparation. Then the floor got the right two coats of epoxy -- correctly mixed and thinned.

Yes, I did get to sell more Part A, but that never, ever makes up for a major mistake like this.  

We all learned a lesson that week.  My lesson learned was: No matter what, be sure the customer really knows and understands how a product works.  The customer’s lesson learned was: No matter what, know and understand how a product works.

Remember, epoxies are a love affair, but true love takes two parts and the two parts must be handled correctly to be successful.

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