The finishing stage of any furniture restoration or woodcraft project determines how the piece looks, how it performs under daily use, and how easily it can be maintained over time. The range of products available — from traditional linseed oil to modern hardwax oils and catalysed lacquers — can be difficult to navigate without understanding what each finish actually does to the wood surface.
Penetrating Finishes vs. Film Finishes
The fundamental distinction in wood finishing is between products that penetrate the wood fibres and those that form a film on the surface. Penetrating finishes — oils and waxes — feed the wood, enhance its natural colour, and provide a low-build look that retains the texture of the grain. Film finishes — varnish, lacquer, shellac — build up in layers on the surface, creating a barrier that is more resistant to water and abrasion but sits visually above the wood rather than within it.
Neither category is objectively better. The choice depends on the intended use, the species being finished, and the desired appearance.
Oils
Raw linseed oil has been used on wood for centuries. It penetrates deeply, polymerises slowly on exposure to air, and provides moderate protection. However, raw linseed oil dries very slowly — several days per coat — and can remain tacky in cool or humid conditions. Boiled linseed oil (BLO) dries faster due to added driers, but can yellow over time, particularly on lighter-coloured woods like ash or birch.
Hardwax Oils
Hardwax oils — a blend of natural oils and waxes formulated for durability — have become a standard choice for furniture and floor finishing in Europe. Products from manufacturers such as Osmo, Rubio Monocoat, and Treatex are available through specialist finishing suppliers in Poland. They provide a natural appearance while offering better resistance to water, heat, and light abrasion than raw oil alone. Application typically requires two thin coats, with light sanding (320 grit) between applications.
Oil-soaked rags are a fire hazard. They generate heat as the oil polymerises and can ignite spontaneously if left bunched up. Lay used rags flat to dry outdoors, or submerge them in water in a closed metal container before disposal.
Wax
Paste wax — typically beeswax or a synthetic equivalent — is one of the oldest wood finishes. It produces a soft sheen and is easy to apply and buff by hand. Wax provides limited resistance to water and is not suitable for table surfaces that will be used for food preparation or that regularly encounter standing liquids. Its main advantage is repairability: worn areas can be re-waxed without stripping the entire surface.
In restoration work, wax is often used as a final coat over oil or shellac on period pieces where a modern-looking plastic surface would be inappropriate.
Shellac
Shellac is a natural resin secreted by the lac insect and dissolved in denatured alcohol. It has been used in furniture finishing since the 18th century and is the traditional finish for many antique pieces from that period. It dries quickly, levels well, and enhances the warmth of the wood grain — particularly on walnut, mahogany, and cherry.
Shellac is not waterproof and dissolves in alcohol, making it unsuitable for surfaces that will be in contact with drinks or cleaning products. In a restoration context, shellac is appropriate for pieces that will be displayed rather than used heavily, and it is reversible — a significant advantage when working with historically significant furniture.
French Polish
French polishing is a technique for applying shellac in thin layers using a cloth pad (called a rubber), building up a deep, transparent finish through dozens of passes. It produces a mirror-like surface that is considered the pinnacle of traditional furniture finishing, but it requires considerable practice and is time-consuming. In Poland, french polishing expertise is concentrated among specialist antique restoration workshops rather than general woodworking shops.
Varnish
Modern varnishes — polyurethane, alkyd, and water-based acrylic types — are the most durable film finishes available. Polyurethane varnish in particular is extremely resistant to abrasion and water, making it a practical choice for tabletops in working environments. However, it is difficult to repair in isolation: scratches and worn patches in a polyurethane surface typically require full stripping and refinishing rather than spot-filling.
Water-based acrylics have improved considerably in recent years and are now available in formulations with durability approaching oil-based polyurethane. They dry faster, have lower odour, and do not yellow as significantly as oil-based products. For oak and other tannin-rich species, use a water-based product designed to be compatible with tannins to avoid discolouration.
Preparation as the Foundation
Regardless of which finish is selected, preparation determines the result. A surface that appears smooth to the touch but has cross-grain scratches from improper sanding will show those scratches more clearly after finishing — particularly under raking light or with stained finishes. The preparation sequence (as outlined in the oak restoration article) should be followed completely before applying any product.
Dust contamination is the most common cause of rough or pitted finishes on dry coats. Work in a clean environment, tack-wipe the surface immediately before each coat, and allow adequate ventilation to carry away solvent fumes and airborne particles during application.