Aluminum oxide finish
For the contractor, the beauty of prefinished hardwood flooring is in the simplicity of installation, with fewer steps on the job site. The hardship of prefinished hardwood is that it will eventually wear, and refinishing it can seem like an overwhelming challenge.
Manufacturers of prefinished flooring continue to make aluminum-oxide finishes harder and harder in order to increase the floor's life. As a result, sanding an aluminum-oxide prefinished floor down the road is one of the hottest issues in our industry today. At a recent trade show, I overheard several prefinished manufacturers boasting there wasn't a machine or product on the market that could sand off their finishes.
It is a puzzle that has contractors and distributors scratching their heads. Some contractors have lost money on jobs when they didn't realize before the job started that the floor was aluminum oxide. Others lose money by choosing to not take on jobs resanding aluminum-oxide-coated wood floors.
Just as finish technology has advanced significantly over the past 10 years, so too has abrasive technology. It's critical for contractors and distributors to keep up. As with any puzzle, the more information you have, the easier it is to solve. You want to work smarter, not harder.
First, you must understand the finish. It does have aluminum oxide in it; however, that additive alone is not what makes it so hard; it is the UVcuring process used in the mills that really creates the hardness.
When finish is applied to prefinished flooring during the manufacturing process, it is done in the most controlled setting possible—as opposed to the conditions on a job site. The contractor can never fully create the ideal curing conditions found in a mill, so there is a large difference in hardness.
Know Your Abrasives
First, be aware that aluminum oxide in powder form is very dangerous to breathe, so it is essential that crews use proper respirators when sanding an aluminum-oxide floor.
When trying to sand that finish, you need to select the right abrasive grain type and grit size. Know what is in the abrasives, because not all abrasives are made the same.
There are four types of abrasive grains commonly used in the wood flooring industry. Only two of them are useful in sanding aluminum-oxide finishes: silicon carbide and ceramic grain.
With silicon carbide abrasives, the grain macro-fractures, meaning that before the grain can dull, it breaks into smaller pieces that essentially resharpen the abrasive.
So, silicon carbide abrasives stay sharp until they die, but they die relatively quickly. That makes silicon carbide the least expensive option per belt price, but product life is shorter.