How to Strip Paint
There are three ways of stripping paint. It is a tedious job but the effort involved is worthwhile to achieve a good surface. Paint can be removed using heat, chemical or mechanical means.
Heat is most effectively applied to oil-based paints. You can use a blow-lamp or-blow torch. A paraffin blow torch is quite difficult to use as it needs priming with methylated spirits. No form of heat should be used near glass, as this may cause it to crack. Heat should not be used near plaster walls.
The modern blow torch may either be one that incorporates a replaceable cannister of gas or an attachment joined by a flexible cord to a gas cylinder. The latter is useful for reaching awkward corners, but is not quite so portable.
Various fittings are available with gas blow torches, from pin-head to wide flames. A paint-stripping head, which spreads the flame, should be fitted to the blow torch. As the flame produced is non-luminous it is necessary to watch the work carefully. Used in conjunction with a stripping knife, the flame must be kept well ahead of the knife.
The flame should be played from side to side. At no time should the flame set the paint alight as this will char the wood. Hold the stripping knife at an angle so that the shreds of hot paint do not fall on the hand. Place something to catch the pieces. When stopping work turn the torch away from the surface to avoid accidental burning.
Start stripping at the bottom of the areas to be treated, covering only a small area at a time. Once the wood is completely bare, use glasspaper to smooth the surface, fill any indentations or cracks and then dust down carefully before priming. Electric strippers are slower and should not be used on damp surfaces.
Chemical strippers can be home-made or commercially produced. Simple strippers can be used on paints that dry by evaporation but not on bituminous cement or chlorinated rubber paints.
Methylated spirits will remove water-based paints, distemper or emulsion; ammonia dissolved in warm water will help remove thein non-washable distemper; cellulose coating can be removed by cellulose thinner.
Modern chemical strippers are spirit-based and should be brushed on to the surface with an old paint brush and left until the paint starts to bubble, when it can then be removed with a paint scraper. It is wise to wear protective clothes and old gloves when using chemical strippers, as these may irritate or burn the skin. If there are several layers of paint to be removed, more than one application of stripper may be needed.
A jelly-type stripper is easier to use than a liquid as it will stay in one place and not run down the surface. Never use a chemical stripper near a naked light as it gives off highly flammable vapour.
Always ensure adequate ventilation when working. Chemical strippers are very useful when stripping window frames – especially metal frames. Burn all the stripped waste. After the paint is stripped wipe down with white-spirit and treat as new wood or metal.
There are various types of paint scraper. One has a double-sided blade, one side of which is serated to cut through the paint film. A shave-hook should be used for scraping mouldings. Using a paint scraper is a skilled job and takes time. It is also possible to sand off old paint using a hand block sander with fine, medium or coarse-grained glasspaper.
A sanding attachment to a power tool will make quick work of the old paint but has the disadvantage of producing clouds of fine dust. Always use with the window open and protect the eyes with goggles. There is also the danger that the wood may be scored too deeply and additional making good will be necessary. If using a sander on large areas it is advisable to use a sand belt or orbital sander.
Try to work in a dust-free room and use lead-free priming paint. In decorating any wooden surface, preparation may include the replacement of sections of wood. This may be due to wet or. Remove the sections of infected wood and treat the surrounding areas. If new sections of wood are used this wood must be knotted and primed before paint is applied.