Remove areas of flaking paint using a scraper or filling knife (putty knife),and then either touch in the bare area with more paint or fill it flush with the surrounding paint film by using fine filler (spackle). Sand this smooth when it has hardened then use a clean cloth moistened with white spirit (paint thinner) to remove dust from recessed moldings and other awkward comets.
If knots are showing through on painted woodwork, sand back to bare wood and apply knotting (shellac) to the knot, then prime and undercoat to bring the new paint film level with the surrounding paintwork and sand between coats. Resinous knots may produce stains which can only be prevented by drying out the knots with a blowtorch.
Every time a surface is re-painted, a little more thickness is added to the paint layer. This does not matter much on wall or ceiling surfaces, but on woodwork (and, to a lesser extent, on metalwork) this build-up of successive layers of paint can eventually lead to the clogging of derail on moldings.
More importantly, moving parts such as doors and windows start to bind and catch against their frames. If this happens, it is time to strip back to bare wood and build up a new paint system. There are two methods of removing paint from wood and metal surfaces. The first is using heat, traditionally from a blowtorch but nowadays more often from an electric heat gun. The second is to use a chemical paint remover, which contains either dimethylene chloride or caustic soda. Heat works well on wood (although it can scorch the surface), but is less successful on metal because the material conducts heat away as it is applied. Chemicals work well on all surfaces, but need handling with care; always follow the manufacturer’s instructions to the letter.
USING A HEAT GUN
- Spray the air stream from the heat gun over the surface to soften the paint film. Scrape it off with a flat scraper as it bubbles up, and sit the hot scrapings in an old metal container
- Use a shave hook (triangular scraper) instead of a flat scraper to remove the paint from moldings. Take care not to scorch the wood if you intend to varnish it afterwards.
- Remove any remnant of paint using wire wool soaked in white spirit and paint working along the grain. Use a hand vacuum cleaner to remove any remaining loose particles paint.
- Sand the wood to remove any raised fibers, and then wipe it over with a cloth moistened with white spirit. Seal the resin in any exposed knots by brushing on liquid knotting (similar) and leave to dry.
- Apply a coat of wood primer or other recommended primer/undercoat to the stripped wood surface. This will provide optimum adhesion for the subsequent top coats, ensuring a really great finish.
FILLING DEFECTS IN WOOD
- Fill splits and dents in wood using filler (spackle) on surfaces that are already painted, and tinted wood stopper (patched) on new or stripped wood that you intend to finish with a coat of varnish.
- Use the corner of a filling knife (putty knife), or a finger, to work the filler into recesses and other awkward to reach places. Smooth the excess filler before it dries and hardens.
- When the filler or wood stopper has hardened completely, use a piece of fine grade sandpaper wrapped around a sanding block to sand down the repair until it is flush with the rest of the wood.
USING LIQUID REMOVER
- Wear rubber gloves and old clothing. Decant the liquid into a polythene (polyethylene) container or an old can, then brush it on to the surface to be stripped. Leave it until the paint bubbles.
- Use a flat scraper or shave hook (triangular scraper) as appropriate to remove die softened paint. Deposit the scrapings safely in an old container.
- Neutralize the stripper by washing down the surface with water or white spirit (paint thinner), as recommended by the manufacturer and leave it to dry.
USING PASTE REMOVER
- Paste remover is especially good for removing paint from intricate moldings because it dries very slowly. Apply the paste liberally to the surface
- Give the paste plenty of time to work, removing paint from intricate moldings especially on thick paint layers, then scrape because it dries very slowly. Apply the paste it off. Wash down the surface with plenty of liberally to the surface.
HOME-MADE PASTE REMOVER
Add caustic soda to water until no more will dissolve. Thicken to a paste with oatmeal and use as for proprietary paste remover. Be particularly careful when using this corrosive solution. If it splashes on the skin, rinse at once with plenty of cold water.