How do you get a clean floor finish from the beginning?

Greg Mihaich, Application Engineer III, DIY/Contractor Markets, Norton | Saint-Gobain

In floor sanding, the standard grit sequence is 36-50-80. But what if you could start with a finer grit, eliminate a step, and still get the final surface quality that marks you as professional?

The product design and engineering team at Saint-Gobain took on the challenge of improving the coarse grits of Norton Red Heat® belts and rolls. Here’s what they discovered on their journey to producing a full-grit sanding sequence with the cleanest scratch pattern available – at every grit level.

Factors That Had to be Considered

From the outset, the goal was to create a product improvement that would work on any floor. That meant looking at real sanding scenarios involving the following:

• Old vs New – how would an aggressive grain work on a seasoned surface and how would it perform on flooring direct from the factory?
• Raw vs Finished – what was the impact of a coarse grain on raw wood and how did it behave differently on a pre-finished floor? Further, did the type of finish (wax, paint, varnish) impact performance?
• Soft vs Hard Wood – how did the type of wood impact the choice of a starting grit in the sequence?

Let’s explore these factors further.

On old floors or pre-finished floors, you commonly have to deal with an existing varnish, wax, or paint, and you have to remove the layers to get down to bare wood. On new floors with brand new wood, the surface is often irregular and needs to be evened. In both cases, you have to start with a coarse grit, but with the new floor, you could most likely start with a finer grit. 

If floors are pre-finished, you first have to determine how tough the coating is. Noted Saint-Gobain Application Engineer Greg Mihaich, “Old floors with a wax coating are especially tough and probably require a 24-grit or coarser grain. Older polyurethane floors let you start with a 36- or 40-grit.” 

When it comes to type of wood, Mihaich said “The softer the wood, you’re going to start a little finer. You’re not going to go too coarse, as that’s going to be too aggressive on a softer wood.” This could cause unintended gouging or scratching, while harder woods can handle the aggression. 

To examine the scratch pattern, a technique known as laser profilometry is used. This technique is a non-destructive testing method used to scan and map a surface. Lighter green and blue indicates a finer scratch while the redder colors indicate a coarser, deeper scratch. In the image seen below, you can see the Red Heat (R955P) scratch pattern after using a 36- and 50-grit sequence on maple wood offers a superior result. Below the color swatches, you can also see a two-dimensional cross-section of the scratch, showing the Red Heat is much more uniform and consistent.

The Red Heat Challenge

The goal was to make coarse-grit floor sanding faster and easier while matching the clean scratch pattern flooring professionals have come to expect from the finer-grit Red Heat belts and rolls. To do that, the product design and engineering team took a long hard look at the manufacturing process and the grain structure in the coarse-grit products.

“It isn’t just about putting more grain on,” Mihaich explained. “We needed to refine the manufacturing process to improve the grain orientation. Doing so gave the new belts and rolls more cutting points and made the grain more available on the surface. This, in turn, improved the initial cut rate by 30%.”

Mihaich strongly recommends that you don’t start any coarser than you have to, regardless of the age, wood type, or finish of your flooring project. The new Red Heat allows you to start with an even finer grit, and possibly reduce the number of grits you have to use. 

“Red Heat is safe to use on everything just because of the performance and the shallow scratch,” he said. “Our real-world testing shows it doesn’t matter whether it’s old wood, pre-finished, or a difficult finish. It could be super hard like oak, or maple. It could be softer like pine or walnut.”

In fact, Michael Comnaire, a Contractor from Ann Arbor, Michigan and an early user, reported “I was able to sand almost 2,000 sq ft with one 60-grit Red Heat belt on new red oak.”

The Finish You Deserve  

For a long time, floor sanding professionals have trusted the finer grits of the Red Heat line to deliver the cleanest scratch pattern in the market. Now with the improved coarse grits, there is a complete Red Heat sanding sequence that can meet the toughest quality demands out there. Plus, the improvements can increase productivity, save time, and simplify inventory management. It’s safe to say that your best finish starts with Red Heat’s new coarse-grit belts and rolls.