Choosing the right sanding block for flat surfaces on small crafts

Many hobby woodworkers in Australia spend their weekends tucked away in a back shed, working on small projects like jewellery boxes, layered ornaments, and signage that need a clean flat finish. Getting that finish right depends heavily on what you sand with, and a dedicated sanding block does far more than just hold the abrasive flat against the surface. Plenty of craftspeople who work through the long summer arvos on clock inserts or scroll-cut keepsakes will tell you that the difference between finger-sanding a panel and using a proper block shows up immediately in the final sheen.

A scroll saw and woodworking supplier like Sloan's Woodshop carries a deeper catalogue of abrasives, files, and craft accessories than most local Aussie hardware chains, and their phone-order service is well known among hobbyists hunting for unusual grits or specialty shapes. With the right block and the right abrasive pairing, even a small panel of Tasmanian Oak ply can be brought to a glassy, lacquer-ready surface without dishing or burn-through.

Why a block makes the surface flatter

When you fold a sheet of sandpaper in half and rub it across a small panel, your fingertips push harder in some spots than others. That uneven pressure rounds corners, dishes out the middle of the panel, and leaves swirl marks that show clearly once a polish or oil is applied. A sanding block supports the abrasive from behind so the entire face presses down at once and removes wood evenly across the panel.

For a small clock insert surround or a layered ornament under 200 mm across, that flatness is hard to eyeball until the light catches it. Customers building keepsake boxes from Jarrah or Blackbutt often only notice the difference once they start wiping on a finish, and any unevenness becomes painfully obvious. Putting the paper on a block gives a smoother, more consistent substrate that takes less finishing time afterwards.

Types of blocks worth keeping in the drawer

There is no single block that suits every job, and serious crafters end up with a small collection. The classic options each behave a little differently, and choosing between them depends on the size and shape of the piece in front of you.

A rubber block flexes slightly and is useful when a panel has a gentle curve or you want to blend a soft edge. A cork block is denser, sits flatter against the surface, and works well on small veneer panels where you want to keep edges crisp. Hardwood blocks, often turned from offcuts, give the firmest backing and are the choice for a true flat surface on hardwood parts. Sponge-backed or contour blocks are softer and better suited to mouldings and shaped edges, so they are not ideal for flat panels but earn their place in the kit.

Around the workshop, the pieces that get the most use are usually a mid-size rectangular block around 100 to 125 mm long for general surfaces, a smaller 50 to 65 mm block for edges and tight spots, and one softer contour block for curved work.

Picking the right grits for your project

The grit you start with depends on how rough the surface is after cutting and how fine you want the final result. For plywood and scroll-cut work, a typical progression starts around 150 grit to remove any fuzz or minor tear-out, moves through 220, and finishes with 320 or 400 before any polish. Hardwoods like Spotted Gum or Brushbox can need an earlier start at 120 if there are visible tool marks, while soft plywoods polish up quickly through finer grits.

For a small craft piece that will be oiled or waxed, stopping at 220 leaves a soft satin sheen. For something that will be sealed or sprayed with a hard lacquer, going to 400 gives a smoother substrate that takes the finish evenly. Many Aussie makers working with native timbers experiment across a few projects to find the progression that suits each species, since Jarrah behaves quite differently to Tas Oak.

The grit range and the block backing both matter in different ways:

• 120 to 150 grit removes tool marks, glue lines, and fuzz
• 180 to 220 grit smooths out scratches from earlier passes
• 320 to 400 grit preps the surface for a polish, oil, or sealer
• 600 and finer is best between coats of finish on sealed surfaces

Size, shape, and how the block sits in the hand

Comfort matters more than people expect, especially on a Saturday afternoon in the back shed when a small project runs longer than planned. A block that fits naturally in the palm reduces fatigue and keeps pressure even from start to finish. A rectangular block around 25 mm thick feels right for most adult hands, and adding a chamfered finger relief on the underside helps keep the grip relaxed through a longer session.

Smaller blocks are useful for narrow strips and the edges of layered plywood pieces, where a wider block tends to tip and round corners. Larger blocks suit broader panels like a clock face insert where you want to cover more area in fewer strokes. Many woodworkers keep a flat cork block for the broad surfaces and a slimmer rubber one for the fiddly bits and inside curves.

When a project needs repeated passes in the same direction, the weight and balance of the block affects how steady the stroke stays. A heavier hardwood block feels planted and steady in the hand, while a lighter cork one lets the abrasive do most of the work. Both work well, and the right one is the one that lets you keep moving without straining through a long session at the bench.

Pairing the block with the right abrasive sheet

Standard sheets of sandpaper can be cut into strips and wrapped around a block, but sticky-backed (PSA) or hook-and-loop sheets make the swap faster. Cutting full sheets into quarters or thirds is usually the most economical use, and a small stack of pre-cut pieces at each grit keeps the workflow moving without constant stopping.

For finer finishes on small craft work, foam-backed or flexible abrasive sheets help the paper follow the panel without digging in. A cork block pairs nicely with these flexible sheets, while a hardwood block works better with stiffer paper where you want maximum flatness. Pre-cut packs from a specialty craft supplier can save money if you burn through sheets on big batches of small parts.

If a project cuts out a lot of intricate details, keeping the block away from inside curves matters, and the right scroll saw blade selection, as covered in this how to choose the right scroll saw blade guide, helps you avoid the tight inside corners that no block can sand anyway.

Caring for your sanding blocks so they last

A sanding block lasts for years if it is kept clean and dry. Dust settles into the cork or rubber surface over time, and wiping the block with a stiff brush between grits keeps the abrasive cutting cleanly. Blocks that are stored in the back shed through a damp winter can develop mildew on sponge-backed or foam-faced types, so keeping them in a sealed container or the workshop drawer helps during the wetter months up the east coast.

A quick check that the working face is still flat every few months prevents problems on finer work. Hardwood blocks can sand slightly out of true after heavy use, and a few passes on a sheet of 120 grit stuck to a piece of plate glass will true them back up nicely. Cork and rubber blocks usually need replacing before they lose flatness, and they are inexpensive enough to keep a couple of spares in the drawer.

A simple care routine keeps the kit in good shape:

• Brush dust from the working face after each grit change
• Store blocks flat in a dry spot, away from direct sunlight
• Replace rubber or cork blocks once the face shows clear wear
• True up hardwood blocks on glass-backed paper as needed
• Keep pre-cut abrasive sheets in a sealed tin to keep humidity out

Many hobbyists who turn their own blocks from offcuts find that the act of truing up a handmade block is a satisfying shop task in itself. With a small kit of blocks and well-chosen grits, even the smallest craft pieces come up flat, smooth, and ready for whatever finish you have planned.