Sanding Grit Sequence for Wooden Projects: A Practical Guide

Woodworkers across Australia, from weekend hobbyists in suburban Brisbane to professional cabinetmakers in Melbourne's inner west, understand that the difference between an amateur-looking finish and a professional one often comes down to the final hours of work. The sanding progression, moving methodically from coarser to finer abrasives, is what transforms a rough-sawn piece of spotted gum or tasmanian oak into a surface that feels silken to the touch and accepts stain evenly. Skipping steps or choosing the wrong grit sequence can leave visible scratch patterns that telegraph through the finish, wasting hours of earlier joinery and finishing work.

For those new to the craft, the array of sandpaper grades on offer at any Australian hardware retailer or specialist supplier can feel overwhelming. Aluminium oxide, silicon carbide, zirconia, and ceramic abrasives each behave differently on timber, and the numbers printed on the back of sheets can vary between manufacturers. By breaking the process into logical stages and understanding what each grit range actually accomplishes, any woodworker can develop a reliable sanding sequence that produces consistent, high-quality results on furniture, turning projects, scrollwork, and smaller craft items.

What the Numbers on Sandpaper Actually Mean

Grit numbers refer to the number of abrasive particles per square inch on a given sheet or disc. A lower number, such as 60 or 80, means larger, more aggressive particles designed to remove material quickly, while higher numbers like 400, 600, or 1000 contain finer particles that refine the surface without cutting deeply. In Australia, most suppliers follow the FEPA (Federation of European Producers of Abrasives) standard, which aligns with the grit sizes familiar to most woodworkers, though some imported products still reference the older CAMI (Coated Abrasives Manufacturers Institute) grading system from North America.

Understanding the relationship between grit number and the actual particle size, sometimes expressed in microns, helps when comparing products from different makers. For example, 120 grit on the FEPA scale measures around 125 microns, while 400 grit comes in at roughly 23 microns. This micron measurement becomes particularly relevant when sanding between finish coats, where a grit that is too coarse will leave scratches visible under the final sheen, but one that is too fine may not provide enough tooth for the next coat to bond.

A common mistake is assuming that moving to a finer grit as quickly as possible saves time. In reality, each grade of sandpaper is designed to remove the scratches left by the previous, coarser grade. Jumping from 80 grit straight to 220, for instance, forces the finer paper to labour against scratches it cannot efficiently remove, leading to uneven surfaces, premature paper wear, and ultimately more time spent on the task. A measured progression allows each abrasive to do its intended work, which is faster overall and produces a cleaner result.

Coarse Grits for Shaping and Dimensioning

The coarse end of the spectrum, generally anything from 40 to 100 grit, is used for stock removal, flattening, and shaping. This is the stage where the belt sander, plane, or drum sander has left tool marks that need to be eliminated before finer work can begin. For Australian hardwoods like jarrah or blackbutt, which are notoriously dense and interlocked in grain, starting with 60 or 80 grit is often necessary because these timbers resist smoothing from finer papers used in isolation.

Many furniture makers working with recycled or reclaimed timber, an increasingly popular choice in Adelaide and Perth markets where sustainability is a strong selling point, begin with 40 grit to remove old paint, surface oxidation, or deep scratches. This initial pass is aggressive and should be followed by 80 grit to erase the deep scratch pattern left behind. Orbital sanders, whether random orbital or sheet-style, work well at this stage, though care must be taken to keep the pad flat and moving to avoid creating dips in the surface.

For turned work, such as the legs of a chair or a decorative spindle, the coarse stage is often handled with a combination of a roughing gouge and then 100 or 120 grit on the lathe itself. This approach saves hand sanding later and helps maintain the round profile. Those who source their timber from a local mill or through community woodworking groups, like the popular Men's Sheds movement found in towns from Cairns to Hobart, will find that the coarse stage is also where most of the dust is generated, so proper dust extraction is essential.

The Critical Medium Range for Surface Refinement

Once the piece is dimensioned and major imperfections are removed, the medium grit range, from roughly 100 to 180, is where the surface truly starts to come together. This stage removes the scratches from the coarse paper and establishes the smoothness that will define how the wood accepts stain, oil, or paint. Skipping or rushing this stage is one of the most frequent causes of blotchy stain absorption and uneven finish sheens.

For most furniture projects built from pine, meranti, or victorian ash, working through 120, then 150, then 180 grit will produce a surface ready for finishing. Those working with open-grained timbers, such as Victorian ash, may want to fill the grain with a timber filler after 150 grit, then sand back with 180 to level the fill. Sanding with the grain direction during these medium stages is important, as cross-grain scratches become much harder to remove later and will show through transparent finishes.

Fine Grits for Pre-Finish Preparation

Fine grits, ranging from 220 to 400, are used to prepare the surface for its final finish, whether that is a penetrating oil, a stain, a sealer, or a topcoat like polyurethane. At this stage, the goal is to remove any remaining scratches from the medium paper and create a uniformly smooth surface that will reflect light evenly. The exact stopping point depends on the finish being applied and the species of timber.

For most oil and wax finishes on Australian hardwoods, 240 grit is the standard stopping point. Going finer than this can actually close off the wood pores too much, preventing the oil from penetrating properly and reducing the depth of the finish. For water-based finishes, which tend to raise the grain more than oil-based products, sanding to 320 grit before the first coat helps minimise the raised fibre effect. For paint or high-gloss lacquer finishes, sanding to 400 grit or even finer produces the smoothest substrate.

It is also worth considering the sanding process itself at this stage. Hand sanding with a firm block, rather than relying solely on a power sander, allows the woodworker to feel the surface and identify any low spots or remaining defects. A useful technique is to wipe the surface with a damp cloth or mineral turpentine, which raises the grain and reveals any rough patches before the first coat goes on. For anyone interested in the broader craft of working with wood, from furniture to more ambitious projects, exploring wood surfboard plans can offer insight into how surfboard builders handle similar finish challenges on shaped blanks.

Working with Australian Timbers: Special Considerations

Australia's native hardwoods present both opportunities and challenges when it comes to sanding. Species like spotted gum, ironbark, and tallowwood are prized for their durability and striking figure, but their density and natural oils can cause sandpaper to clog more quickly than it would on softer imported timbers. Frequent cleaning of the sandpaper, using a rubber cleaning stick or simply knocking the dust out, helps extend its working life and maintains a consistent cut.

Another factor to consider is the moisture content of the timber. Australian climate zones vary significantly, from the humid tropics of far north Queensland to the dry heat of inland regions, and timber purchased from a local supplier may not be at the equilibrium moisture content of the workshop. Allowing the timber to acclimatise in the shop for a few weeks before final dimensioning and sanding helps prevent movement after finishing, which can cause cracks or raised grain. Many Australian woodworkers use a moisture meter, readily available from places like Bunnings or specialist timber suppliers, to confirm the timber is stable before committing to final sanding.

Australian standards for timber products, including AS/NZS 1080 for timber drying and AS 2796 for timber stress grading, provide guidance on moisture content and structural grading, but finishers should also be aware of the volatile organic compound (VOC) regulations in their state. For example, the New South Wales Environment Protection Authority has specific requirements for finishes used in commercial applications, and many professional workshops now opt for water-based or low-VOC products to meet these requirements. Whatever finish is chosen, sanding to the correct grit for that specific product is essential, and suppliers like Sloan's Woodshop offer a range of abrasives suitable for different stages of the process.

Final Polishing and Between-Coat Sanding

Once the finish is applied, the sanding journey is not quite over. Most multi-coat finishes, including polyurethanes, lacquers, and conversion varnishes, require light sanding between coats to ensure proper adhesion and a smooth final film. This between-coat sanding uses very fine grits, typically 320 to 400, and is done with a fine sanding sponge or a random orbital sander fitted with a soft interface pad.

The purpose of between-coat sanding is not to remove the previous coat but to scuff the surface enough to provide tooth for the next layer. Using too fine a grit, or sanding too lightly, can result in poor adhesion and eventual delamination. Using too coarse a grit, or pressing too hard, can cut through the previous coat and create the need for a full re-sand. A light pass, followed by a tack cloth wipe-down, is usually sufficient.

For the final polish, on projects destined for a high-gloss finish, some woodworkers in cities like Sydney and Melbourne work their way up to 2000 grit or finer, using wet-and-dry paper with water or a lubricant. This produces a mirror-like surface on dense hardwoods, though it is rarely necessary for furniture that will see daily use. Most pieces look their best with a finish that highlights the natural figure of the timber, and stopping at 400 grit under the final coat typically strikes the right balance between clarity, durability, and the warmth of the wood itself.