Preparing an older surface for painting

Preparation of an old painted surface:

1. Inspect the old paint: if it is sound and firmly stuck, only cleaning and light rubbing are needed; if flaking, cracked or blistered, remove it fully.
2. Remove old paint: Scrape with a scraper or wire brush, or use a paint remover or blow lamp for thick coats.
3. Clean dust, dirt, oil, grease, mould and efflorescence with a brush, soap or detergent water, then rinse and let dry.
4. Rub down with sand paper (glass paper) to roughen glossy areas and give grip for the new coat.
5. Repair: Fill cracks and holes with putty or filler, and sand smooth.
6. Rust and knots: Remove rust from metal with a wire brush; treat bare patches and knots with primer or knotting.
7. Prime bare spots and then apply the new undercoat and finishing coats.