Be it for carpentry, a little bit of do-it-yourself home maintenance on your hardwood floors or finally getting around to giving an old piece of furniture a much-needed fresh coat of paint, sanding is an essential process cropping up in the life of your average DIY enthusiast, no matter how tedious and time-consuming it may sometimes feel. Sanding down a surface, and essentially smoothing it out, can constitute prep-work – getting rid of any bumps, scratches and dings before you paint a surface down, or removing old varnish to put down a new layer – as well as the final finish, leaving surfaces like wood and metal sleek and flawless. Sanders can also have other applications, including sharpening and grinding knives.
To get the right effect, though, rather than a dresser top that looks like a map of crop-circles or a staircase step with a depression left in the wood, the user needs to familiarize themselves with the technicalities of using a sander, and be able to distinguish which type of this power tool is suitable for which jobs. Though you can choose to sand by hand – though this is definitely going to require more elbow-grease and time – electric sanders, if chosen properly and handled right, can deliver exceptional results as well.
Grit
Sandpaper is graded based on grit, or how much abrasive material there is per square inch – the lower the number, the coarser the grit, while the higher the number, the finer the grit. While you technically can start off with higher numbers, be prepared for this to take a lot more time than you’d be using if you start off lower, around grades 60-80 – coarser grits remove material faster, so they’re more effective when getting rid of rust on metal surfaces, or smoothing out joints or uneven surfaces on rough wood, while following this up with progressively finer grits removes any scratches and swirls left by previous grits for a smoother finish. For DIY woodwork projects, sandpaper grit can go as high as 320 – for polishing metal, the ideal number can be anywhere as high as 600 to 2,000 (the latter often ideal for removing scratches on car body paint).
Sandpaper type
The type of sandpaper you use will vary depending on the type of surface you’re going to sand. For metal, closed-coated sandpaper (the entire surface is covered by abrasive material) is suited for tackling the challenge. Sandpaper made of aluminum oxide or silicon carbide is typically recommended.
Meanwhile, the type of wood you need to sand will determine the type of sandpaper you’ll require for best results. Garnet paper is often used for hardwoods and for achieving a smooth finish for woodworking projects, while coarser grits to remove imperfections, paint, scratches and so on could be found in aluminum oxide or ceramic sandpaper. The latter leaves a very rough finish, and is recommended more for prep work on thick pieces of wood, rather than, for instance, on plywood or veneer.
Sander types
Now that we’ve got the basics out of the way, let’s take a closer look at the three main types of sanders available to us for home use, and what they’re good for.
Belt sanders
These are the most heavy-duty of the lot, ideal for use on large, wide, flat surfaces. Better recommended for the experienced sander than a novice DIY trial-runner, this machine works quickly and aggressively to remove a lot of material, typically used at the beginning of the sanding process to get rid of any imperfections before you move on to finer grits for a smoother finish. Often outfitted with ceramic sandpaper, belt sanders are the right choice for levelling very rough or uneven surfaces, shaping wood and sanding over curved and rounded edges, as well as for removing old paint and varnish off surfaces in need of a new or fresh coat.
As the name suggests, the sander operates using a sanding belt looped over two cylindrical drums, rolling to move the belt in a linear fashion as you sand over your desired surface. If sanding wood, always remember to sand with the grain, no matter what type of sander you’re using, rather than against or across it, for the smoothest and most immaculate finish. A rookie mistake to avoid, also with any type of sander, is to push down on your machine as it runs – let the machine’s weight regulate the pressure.
Although we’ve already mentioned this, it’s worth repeating – belt sanders are heavy-duty machines, and if you’re not careful they may end up taking a chunk out of the surface you’re sanding, leaving it uneven or with a depression. Some practice and experience is needed to operate one without winding up with a damaged project, since the machine can often be difficult to control for a beginner. We’d recommend starting off with the compact and easier to control 3 x 18-inch standard if this is your first time operating one.
Orbital Sander
Lightweight and more user-friendly, orbital sanders are better suited for getting the perfect finish, smoothing out a freshly-dried coat of paint or polish, sanding out hardened putty and giving your woodworking projects the sleekest finish. The sanding pad, square-shaped and with two clamps holding on to a fraction of a standard sheet of sandpaper cut to size, moves and vibrates in small orbits and can subsequently be used to sand in any direction.
Random Orbit Sanders
These are arguably the most versatile, and likely the sander a woodworks-enthusiast would be sure to have in their toolkit. With a circular pad which both vibrates and moves in orbits, this sander combines the two motions to eliminate the likelihood of leaving behind swirls when you’re done sanding. Although not as ideal for rough-use sanding as belt sanders, this sander can nonetheless be used for both prep-work removal of material and for getting that sleek, pristine finish for our carpentry projects, without any weird scratches or swirls left behind.
For more detailed projects…
If you’re working an intricate surface with many nooks and crannies needing attention, you could opt for a detail sander to get into areas other sanders find hard to access. Sanding by hand is also an option for really getting into any crevices you can’t otherwise reach.