Gardening Calendar Zone
Preparing previously finished metal
If paintwork on metal window frames is in good condition it can be repainted with relatively little in the way of preparation. Just wash it with sugar soap or a solution of soda crystals, rinse and dry. Then sand the paint lightly, with fine sandpaper wrapped round a cork block, in order to create a key for the new coat of paint. Before starting to paint, thoroughly clean off any dust.
If the paintwork is in poor condition, however, it will require considerably more work before it can be repainted. Be sure to protect your eyes with goggles before brushing off all the loose material – rust as well as paint – using a sturdy wire brush. Next, scrub the metal with a solution of sugar soap or soda crystals, and rinse. Wipe down the entire surface with white spirit on a clean rag to remove any remaining grease. When it is thoroughly dry, paint rust killer onto bare or rusty patches, paying special attention to ensure it thoroughly permeates fixing boltheads, hinge areas and joints. When this has dried, fill holes and depressions.
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The preparation of doors and windows for a new finish requires little in the way of specialist tools and equipment. In addition to the items described below you will need a screwdriver for removing ironmongery and door furniture before starting work.
• Knotting solution an oily sealant made from shellac and methylated spirit which is painted onto the knots in new timber, especially pine, to prevent them weeping resin ( 204-205), which can stain a paint finish.
• Sugar soap or soda crystals washing existing paintwork with sugar soap or old-fashioned soda crystals dissolved in hot water is a marvellous way of removing dirt and grease, and even decades of caked-on grime.
• Liquid sander a solution for cleaning surfaces prior to applying a new finish. It is particularly useful for cleaning and smoothing intricate mouldings and corners.
• Sandpaper or abrasive paper essential at every stage of preparation to feather the edges of cracked or flaked paint or varnish; to create a key on existing finishes ready for the next one; to smooth and level dried filler after application; and between new coats of paint for a really glossy result.
• Wire brush extremely useful for removing flaky paint and rust from metalwork.
• Hot-air gun the cleanest, neatest and, some say, the safest way to strip paint is using a hot-air gun. Shaped rather like a hairdryer, this machine melts paint, even layers deep, which can then be scraped off with a scraper or shavehook. Some have integral scrapers and in the framework with metal filler. Allow this to dry, then sand all over to create a smooth, even surface for painting. If priming the surface first, use a primer formulated specifically for metal which contains rust inhibitor.