A new coat of paint can transform a room. But you’ll be wasting your time if you don’t make sure the surface is properly prepared. A sound paint film, even if it is several layers thick is a perfectly suitable base for repainting. Just give it a quick rub down with medium coarse glasspaper wrapped round a wood or cork block, dust well and the surface is keyed ready for its first coat.
A heavy build-up of paint on the closing edges of doors and windows can result in sticking and adding another coat of paint on top of the old layers will only accentuate this problem. There is no need to remove the old paint from the whole surface though; trimming away from the edges themselves is sufficient. If the paint is peeling, pitted, badly chipped or crazed, however, then the only way you will achieve a satisfactory and long-lasting surface is to strip back to bare wood ready for filling and making smooth before starting to repaint. There are three ways of stripping: by hand (or mechanical) sanding or applying chemicals or heat.
Hand sanding
This method is suitable only when a very thin film of paint has to be removed. Use a piece of medium coarse wet and dry glasspaper wrapped round a wood or cork block and be prepared to exert plenty of elbow grease when rubbing. Wetting this type of glasspaper reduces the spread of dust.
Mechanical sanding
There are various sanding attachments for electric drills, but circular ones are not easy to work with and there is a real danger of scoring the wood if the correct technique is not used. If the wood is scored, you will have to do a great deal of repair work before you can repaint it. A drum sander is the best attachment to use. This comprises a foam drum onto which an abrasive belt is fixed. The belt action is along the grain so avoiding any circular scuffs to the surface of the wood. The action is efficient and quick, the only drawback being excessive dust. Various grades of abrasive belts, from coarse to fine should be used. When dealing with a really thick film start with a coarse grade and switch to a fine grade for the final sweep.
After a quick dusting down and a wipe with a cloth dampened with white spirit, you can begin repainting. You can take off a heavy coat of paint more rapidly with a special power drill accessory known as a paint and varnish remover. This is a chuck-held metal disc with perforations punched through the surface to allow the loosened material to pass through the disc without clogging. When sanding, take the work outside whenever possible to avoid too much mess indoors and, for personal safety, use a dust mask (to cover up your nose and mouth) and protective spectacles or goggles.
Chemical stripping
Decorating shops stock chemical strippers under various brand names. Use a jelly type as it will adhere to the paint longer and will not run on vertical surfaces. Chemical stripper can be expensive so it is not really suitable for large areas, nor where a thick film otpaint has to be removed as two or even three applications may be needed before bare wood is reached. Pour a little of the stripper into a metal container and, using an old paint brush, apply liberally. After a few seconds the paint will start to shrivel and you can remove it with a flat paint scraper. Keep this as upright as possible to prevent digging into the wood and damaging the surface. To strip paint from mouldings or other awkward crevices use a shave-hook. The best type is a heartshaped scraper which has a series ofintricate shapes around the workhead lor dealing with all types of angles and curves. When all the old paint has been removed, apply a thin layer of stripper and finish off by rubbing over the surface with medium steel wool. To make the wool last longer, tear off small amounts from the main ball and, as you work, turn the piece inside out until all the edges have been used. This final rub over will remove all small nibs of paint not obvious to the eye. Chemical stripper will remain in small traces on the surface and must be neutralized before applying fresh paint. So, using a constant supply of clean rags, wipe down the surface thoroughly with white spirit or the solvent recommended by the brand manufacturer. You must wear an old pair of leather or thick rubber gloves, protective spectacles or goggles and preferably a dust mask as well. And remember to protect the floor covering with newspapers.
Heat stripping
Blowtorches have come a long way since the days when they were filled with paraffin or methylated spirit and needed energetic pumping before igniting. Today they are much easier to use since the simple burner head unit fits onto a throw-away gas cartridge or you could use an electric one which is safer. When ignited you can adjust the power of the flame by turning a ridged screw. Before tackling your surface, it is worth getting the feel of the blowtorch by practising on a scrap piece of painted wood. Hold the blowtorch at a constant distance, about 150-200mm from the paintwork. Play it back and forth across a small area and when the paint starts to wrinkle and melt it is ready for scraping off. If the paint sticks, play the flame over the area again and resume scraping. Take care not to scorch the wood by concentrating the flame for too long on one spot.
Switch to a chemical stripper if the paint is thick in mouldings and around window frames, where a build-up of heat can easily crack the glass. If you do scorch the wood, glasspaper or scrape back to bare wood before repainting. As with chemical stripping, some paint particles will be left and these should be glasspapered down. Be careful when using the flame under the house eaves as birds often build their nests here and these can be easily set alight. When you are working near open windows, tie back the curtains and place a metal sheet on the floor to catch the hot paint peelings. Wear an old pair of leather or rubber gloves and protective spectacles or goggles.