Which finish do I need

Describes how freely the coating flows. You pick it to suit the spray/roll/curtain method; it drops as the material warms up and you adjust it by adding thinner. Measured with a Ford cup (100 cc, 2/4/6/8 mm orifice) as the time in seconds for the cup to drain.

Too thick and it atomises badly and orange-peels; too thin and it sags and builds too little film. Right working viscosity = right amount of thinner.

For pseudoplastic and thixotropic coatings viscosity isn't a single number: it differs in the can, while stirring, while spraying and while drying. The coating has to be thin enough to spray and level, yet thick enough not to sag while drying and not to let pigment or matting agent settle in storage.

Explains why material looks thick in the can but sprays fine — and why you must stir it before use.

The coating's ability to thin out under mechanical action and build back up at rest (with thixotropic fluids viscosity changes over time at constant shear, unlike pseudoplastic ones). In practice: no runs on vertical parts, which is why it's a must for chairs. Downside: it levels worse, so on flat horizontal panels you can get unfilled pores or orange peel.

Pick by part: thixotropic for chairs, mouldings and verticals; non-thixotropic for flat horizontal panels.

Gloss is the surface's ability to reflect light without scattering, as % of incident light against a black-glass reference. Matt wood looks more natural and hides imperfections; gloss looks richer and deeper. Actual gloss also depends on surface prep, how much you put on, the application method and drying conditions. T-Color glossary classes: 1–10 dead matt, 11–30 matt, 31–40 medium matt, 41–50 semi-matt, 51–80 semi-gloss, >80 gloss.

Sets the look of the piece; orders often specify an exact number (e.g. 10, 20, 30 GU).

The time you have to use the mixed material before curing and rising viscosity make it unusable. Critical for chemically curing coatings (PU, polyester). Usually tied to drying speed and depends on temperature. Officially it's the time it takes the mix viscosity to double (Ford cup, 20 °C).

Tells you how much to mix at once — mix more than you can spray in time and the rest is waste. Shorter in hot weather.

First of four stages: the top skin has dried, dust won't stick, and the part can be taken out of the clean room.

Tells you how long the part must stay in the booth/clean zone.

Second stage: the film no longer feels tacky; parts can be handled and moved around the shop.

Plans handling and moving parts within the shop.

Third stage: most of the solvent has left the film; the part can be stacked, sanded or given its next coat.

The key number for scheduling: when you can sand the primer and recoat.

Fourth stage: after this, every physical and chemical process forming the film is finished. Only then can you test or polish the coating.

When you can polish, pack tightly and hand over for use.

How strongly the coating sticks to the surface. Especially important on 'difficult' woods, foils and papers — that's what adhesion primers are for. Intercoat adhesion matters too when you combine different primers and topcoats. Improved by keying (sanding); ruined by silicone, oils and waxes.

Delamination is the most expensive defect — full rework. Hence the rules on intercoat sanding and primer/topcoat compatibility.

Mass fraction of non-volatiles left after curing. Higher solids = thicker dry film. High-solids primers are used for closed-pore finishes or to build a thick primer coat in one pass. High-solids (low-solvent) coatings usually dry slower. Glossary rule of thumb for primers: >40% high build, 35–40% medium-high, <35% medium-low.

Tells you how many passes it takes to close the grain and your real coverage per m² of dry film.

The film's ability to take mechanical abuse. Hard lacquers go on high-wear surfaces: tabletops, bar counters. For industrial coatings, how fast hardness builds matters too — it decides when the piece is ready for use. The flip side of hardness is brittleness, so be careful building hard lacquers thick.

Pick topcoat by duty: hard for tops and counters; balance with elasticity on solid wood that moves seasonally.

The film's ability to recover after deformation and follow the substrate's movement without cracking or peeling. Wood moves with temperature and humidity swings (cold warehouse → heated flat, damp rooms). Too little elasticity = cracks and flaking.

Matters for solid wood, windows, doors and anything stored or shipped unheated.

Resistance to prolonged mechanical wear — one of the main drivers of coating life. Best results come from the right balance of hardness and elasticity. Floor (parquet) lacquers in particular need high abrasion resistance.

Critical for floors, stairs, tabletops and bar counters.

The coating's ability to withstand acids, alkalis, salts and solvents. For furniture the first things checked are water, alcohol (vodka, red wine) and coffee — especially for kitchens and bathrooms.

Drives the system choice for kitchens, bathrooms, tabletops and hospitality furniture.

Ability to keep its colour under sunlight, whose UV pushes lacquers and enamels towards yellow. Matters for exterior finishes and for white/light colours where yellowing shows most. Depends on pigment quality and, for PU, on the isocyanate in the hardener: aliphatic is stable, cheap aromatic yellows. Remember the wood itself also changes colour in light.

White enamels and pale clears need a lightfast (aliphatic) system.

A pigmented coating's ability to fully hide the original colour when applied evenly, expressed in g/m². Inorganic pigments hide better; organic ones (especially yellows, reds, oranges) give brighter, cleaner shades. Best results: blend both or use a tinted primer.

How many enamel coats a bright colour needs and whether to tint the primer.

Ability to carry electrical current with minimal resistance. Important for electrostatic spraying: the higher it is, the better the droplets are pulled onto the part.

If you spray electrostatically (chairs, legs, spindles) the material must have suitable conductivity.

The coating's ability to withstand the destructive action of wind, rain, sun and temperature swings.

Key for windows, exterior doors, cladding and garden furniture.

The coating's ability to resist swelling, blistering and other damage from moisture.

Bathrooms, kitchens, MDF fronts in damp rooms.

Ability to withstand many freeze–thaw cycles without visible damage or real loss of strength; applies both to the film and to the material in the can.

Furniture shipped/stored unheated in winter; waterborne coatings must not freeze in the can unless rated.

A key property of waterborne dispersions: dried below the MFFT, the polymer won't coalesce into a continuous film and the coating cracks or chalks. Coalescents lower the MFFT.

Don't spray waterborne in a cold shop.