T11 Finishing: outdoor finish steps; oil vs water-based; finishing and the environment (3–5 marks) · Industrial Technology Timber

T11 · Finishing: outdoor finish steps; oil vs water-based; finishing and the environment (3–5 marks)

Fits: 2020 Q15 (5), 2016 Q13 (3), 2017 Q13 (3). Also 2025 MC10, 2023 MC10, 2021 MC9, 2022 MC9 · 226 words · 7 chunks

T11.1 · NameFor an outdoor hardwood bench, use a penetrating exterior oil or decking oil with UV and water-repellent additives.T11.2 · PreparePreparation: fill any holes with exterior filler, then sand through the grits, for example 120 to 180, with the grain. Raise the grain with a damp cloth, let it dry and sand lightly again, then remove all dust.T11.3 · ApplyApply the oil with a brush or cloth along the grain, let it soak in for the recommended time, and wipe off the excess. Apply two or three coats, allowing drying time between coats, and re-oil regularly as it weathers.T11.4 · OrderCorrect general finishing order: sand, raise the grain, sand, apply finish, then buff/polish (2025 MC10).T11.5 · Oil-basedOil-based finishes give a warm amber depth, flow out well and are very hard-wearing. However, they dry slowly, smell strongly, are flammable, need mineral turpentine to clean up and yellow over time.T11.6 · Water-basedWater-based finishes dry quickly, have low odour, stay clear and clean up with water. However, they need more coats, can raise the grain and lack the rich glow of oil.T11.7 · EnvironmentTo reduce environmental harm: choose low-VOC water-based products, apply only the amount needed, use spray booths with filters, and never pour solvents down the drain. Take waste finish, solvents and soaked rags to an approved chemical-waste facility. Store oily rags flat to dry or in a sealed metal container, because they can self-ignite.

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