Grit and abrasive material both matter more here than brand alone — the right combination depends on the machine, the wood, and which stage of the job you're on.
Working Through the Grit Sequence
Floor sanding is done in stages, moving from coarse to fine rather than jumping straight to a fine finish. Coarse grits (16–40) strip old finishes and level uneven boards. Medium grits (50–80) remove the scratch pattern left by the coarse pass. Fine grits (100–150) prepare the surface for staining or sealing, while very fine grits (180 and above, up through 600–1200) are typically used between coats of finish for a smooth final result rather than on bare wood.
Choosing the Abrasive Material
Not all abrasive grains behave the same way. Silicon carbide discs, common in the coarser grit range here, cut aggressively and suit general floor sanding. Zirconia abrasives, used on the heavier-duty sanding belts, are built to withstand more heat and pressure without breaking down quickly, making them a common choice for bigger belt sanders working through old finishes. Aluminium oxide is a versatile, widely-used option across both discs and belts, valued for a good balance of cut speed and lifespan. Ceramic abrasives sit at the premium end, generally lasting longest under heavy use, which can offset a higher price on large jobs.
Discs vs Belts
Discs are used with orbital and edging sanders — smaller machines suited to finishing passes and getting into edges and corners a large sander can't reach. Belts are used on bigger drum or belt sanders for the main body of the floor, covering more ground faster during the coarse and medium stages of a job.
Matching Hole Pattern and Size to Your Machine
Getting the size and hole pattern right isn't optional — a disc that doesn't match your sander's dust extraction ports will clog faster and leave more dust in the room. Single-hole and multi-hole (8+1) Velcro discs are sized and drilled to fit specific machines, including Festool sanders and Bona edgers, so it's worth checking your machine's compatible disc size and hole count before ordering rather than assuming one size fits all.
Common Questions About Sanding Abrasives
What grit should I start with on an old floor?
This depends on the condition of the existing finish and how uneven the boards are, but a coarse grit (16–40) is typical for stripping back an old finish or levelling boards, working progressively finer from there.
What's the difference between zirconia and aluminium oxide abrasives?
Zirconia generally withstands more heat and pressure, making it well suited to heavy-duty belt sanding. Aluminium oxide is a versatile all-rounder used across both discs and belts, balancing cut speed with a reasonable lifespan.
Do I need a specific hole pattern for my sander?
Yes — discs are made to match specific machines' dust extraction ports. Using a disc with the wrong hole pattern or size can reduce dust extraction and clog the abrasive faster.
How fine should I sand before applying a finish?
This depends on the finish. Oils and lacquers generally need the wood sanded to a fine grit (100–150) on bare wood, with even finer grits sometimes used between coats for a smoother final result — check the specific product's recommendation.
