Net-Backed Abrasive Sanding Discs
Sanding is a lot like housework – it’s not all that enjoyable, but it needs to get done. For the most part it’s tedious and repetitive; you don’t really see positive results until the job is almost done, and it takes up valuable time that most of us would much rather spend on just about any other activity. But sanding is incredibly important if you want to achieve a beautiful finish that does justice to your project.
One of the most commonly used finishing tools is a random orbital sander equipped with hook-and-loop sanding discs. The discs typically have five to eight holes through which dust is extracted, either to a dust bag attached to the sander or by means of a dust extractor. By far the most popular type of disc is stearated aluminum oxide.
If you do a lot of sanding you’ll want to know about ‘net-backed’ or ‘mesh’ abrasives. These products aren’t new to the market – they’ve been widely used in the automotive and metal finishing sectors for decades and are gaining a lot of traction in the drywall sector. However, they’ve yet to catch on with the general woodworking community. This might be due in part to the price differential – net discs can cost more than twice the price of standard discs.
The surface of a net abrasive disc looks somewhat like the netting you see on a screen door. It’s made of a woven polyester or nylon mesh with a stiff hook-and-loop backing. The entire surface is peppered with hundreds of tiny holes onto which an abrasive grit (aluminum oxide or ceramic grit) is bonded. As a result, dust-laden air can pass through the disc’s entire surface area, compared to the five or eight holes through which air passes on a standard sanding disc. Because the net disc has such a large open surface area, your dust extractor can pull out virtually all the dust generated by the disc. This means there will be precious little dust getting into the air you breathe. Net discs don’t clog up with dust like standard discs. This prevents dust pills from forming on the face of the disc, which can mar the work surface. It minimizes dust contamination on your work surface, too.
You can use these discs with pad protectors that help prevent wear on your sander’s backing pad and also increase air flow through the net abrasive discs.
One of the main benefits of net-backed abrasive discs is the fact that air flow can take place all over the surface of the disc, increasing dust collection. (Photo by Rob Brown)
A backing pad can be used with net-backed abrasives to improve dust extraction and protect the sander’s pad from wear and tear. (Photo by Mirka)
The Mirka Abranet line of abrasive discs is available in a wide range of grits.
The Diablo SandNet discs from Freud are only available in 5" diameters but come in a wide range of grits.
The abrasives in the Granat NET line from Festool have a polyester backing and are available in a wide range of grits.
I used these discs over a two-week period in my shop, and I found that they cut noticeably quicker than standard discs. They also last considerably longer. Freud, for example, claims that their SandNet discs last 10 times longer than conventional discs.
Because they excavate dust so effectively, there isn’t the same amount of heat buildup that you’d find with standard discs, and when necessary, you can clean them with compressed air. This may account, in part, for why the discs last longer and why the finished surface looks better. They can be used for wet or dry sanding, and when used for wet sanding you won’t experience any surface skidding (hydroplaning) as you might with wet/dry sandpaper. An additional benefit of net discs is that, unlike standard discs, you don’t have to fuss about trying to align excavation holes on the disc with the corresponding holes on the sander pad.
Why Go Net
Here are 10 reasons you may want to give net abrasives a try.
We looked at net abrasives for standard 5″ and 6″ disc sanders from three manufacturers. Brands that we didn’t look at include 3M, Norton and Sia Abrasives. Some manufacturers offer mesh abrasives in larger-diameter sizes for drywall sanding and in various sheet sizes.
Mirka is the name synonymous with net abrasives. They offer the widest selection of styles and sizes of abrasive and are the least expensive. The Abranet line will be of greatest interest to woodworkers. They’re available in 13 grit formats from 80 to 1000. The Abranet Ace HD, which come in four grits, from 40 to 120, are embedded with ceramic grit, have a much heavier backing and are designed for very rapid stock removal. Mirka also has an assortment pack of nine discs in the 80- to 600-grit range, which makes for a good starter set.
Freud’s Diablo SandNet discs are only available in 5″ sizes, and in nine grit sizes from 60 to 400. Like the Mirka discs they have a durable nylon backing.
Festool’s Granat NET abrasives just came onto the market in 2018. There are nine grit sizes from 80 to 400. Unlike the other brands, they have a polyester backing, which isn’t as strong as nylon but offers better moisture resistance.
Micro-Mesh: The Non-Abrasive Abrasive
You may have heard of Micro-Mesh cushion-based sanding discs. These are not to be confused with net abrasives. Micro-Mesh abrasives are widely used for buffing plastics and fibreglass – and by savvy woodworkers for smoothing and polishing finish coats to a scratch-free, high-gloss shine. They’re made of silicon carbide or aluminum oxide crystals bonded to a flexible cloth and foam backing and are available as 5″ and 6″ discs (as well as other formats) from 1,500- to 12,000-grit with either an H&L or PSA backing. Micro-Surface.com