What exactly are solids? In water-based hardwood floor coatings, solids are whatever is left on the floor after the coating cures. Solids are usually expressed as a percentage of weight, a coating with 50% solids will be half gone after it dries. Still confused? To put it simply, the higher the solids, the more coating you will have left on the floor after it dries. There are several myths floating around the hardwood floor finish industry regarding solids. Keeping this in mind, let’s examine three biggest misconceptions about solids.
Myth #1 – The more solids the better
Solids can be anything that does not evaporate during the curing process. As you know, the word “anything” can mean a variety of things. You have to look at what makes up the solids and what each of them does. Merely comparing finishes by percentage of solids is not an adequate test of their capabilities and performances. Finish solids are often a blend of several ingredients, each having a specific purpose. Many of these have nothing to do with how long a finish will last. These various ingredients help the finish resists scuffs, reduce bubbling, improve adhesion, alter clarity, regulate sheen, and last but not least, determine overall durability. Ingredients used to adjust sheen or to control bubbles may add to the solids, but they do nothing for the durability.
Myth #2 – Taber abrasion tests are always accurate.
The only scientific data less reliable than a Taber abrasion test result is what you get from your local weatherman. The American Society of Testing and Material (ASTM) state the accurate of on Taber abrasion machine compared to another that may vary up to a range of 90 to 106 percent. This is considered the normal range and means the tests can be off by 100% and still have been considered accurate. These results can occur even when documented test procedures are used. In a nutshell, this is why we don’t value Taber abrasion test as the one and only way to determine the durability of a finish.
Myth #3 – Pure urethane solids are best
Like the first myth, this one concerning urethane solids is also incorrectly based on the concept “if a little of something is good, than a lot must be better”. Many people (and some manufacturers) think omitting acrylic will improve a water-based coating. We’ve found the opposite to be true, and we are not alone. Like most everything else you can buy there are expensive acrylics and inexpensive, filler, acrylics and the same is true for urethanes. It is possible to have more expensive acrylics in a finish formula than the urethane used in the same formula. For flooring applications urethane resins work best when blended with acrylics.
Micah Petersen, Product Manager for Basic Coatings, spent the first 15 years of his career as a Research and Development Chemist before becoming Product Manager. In his free time he enjoys spending time with his family and a multitude of outdoor activities. For further questions regarding hardwood floor care and Basic Coatings, please email Micah at Micahblog@basiccoatings.com.