DIY Method of Painting and Preparation

It may generally be assumed the method of application of all types of decorating materials, inside and outside the house, is to start from the top and work down. In this way completed work is not spoiled by splashes of paint and falling dust brushed from overhead surfaces.

The first part of the room to tackle is the picture rail if there is one of course. This should be followed by the window or windows and the next part of the job in logical sequence is the door and door-frame, finishing with the skirting-board. So start with the picture rail first and attack the old surface vigorously. The preparation may vary according to the state of the old surface. If the old surface is smooth and unblemished it is best cleaned down with sugar-soap. Use of sugar-soap is the one process in home decorating that is done in reverse to the usual top-to-bottom order. When cleaning down with sugar-soap it is advisable to start from the bottom and work up or runs of dirty water may stain the bottom of the work, and it will be found impossible to remove these stains After washing down with sugar-soap the work should be rinsed and dried and may, before rinsing, be rubbed down with grade middle-two waterproof glass-paper. The glass-paper should always be used with plenty of force behind it and the paper should be changed as it becomes worn. Glass-paper is always used with the grain of the wood, and the grain of the wood runs in the longest direction of the piece — picture rails, window frames, doors, door-frames or skirting-boards.

If parts of the woodwork — and this particularly happens round window-frames that are exposed to strong sunlight — are blistered, but not badly blistered, the surface may be smoothed by scraping the woodwork with a shave-hook followed by vigorous rubbings with a water-lubricated pumice-stone. Any remaining signs of blister scars may then be filled in by using a patent powder-filler mixed with water and applied to the surface with a broad stripping knife. After allowing the powder to harden — this is best left overnight — the surface should be scrubbed with glass-paper and cleaned off with a duster before painting. If the blisters are very bad or if the old surface has been neglected and is thickly encrusted with gritty and treacly paint or varnish, it may be necessary to remove all the old paint, either by using a blowlamp, or a solvent.

This is rarely necessary for interior painting except in the case of a very old house, the paintwork of which has been coated so many times that the mouldings and edges are thickly encrusted with multiple layers of paint. For most surfaces all that is necessary is a vigorous rub down with glass-paper. Any bared surfaces or repairs to woodwork with new timber should be given special initial treatment consisting of coating knots, and a small area surrounding the knots, with patent knotting, which is applied with a small brush. Follow the knotting with the application of one priming coat which may be a pink primer or aluminium priming paint. Priming is only necessary on new or bared timber. However, when it is necessary to make a drastic colour change, say from black paintwork to very pale cream or white, a coat of aluminium paint may be applied before the usual undercoatings to kill the dark colour.

Simple mouldings may be sanded down by wrapping the glass-paper over a decorator’s cellulose sponge instead of cutting a shaped block. After finishing the picture rail and dusting it, deal with the windows and frames next. When sanding windowframes take care to avoid scratching the glass with the abrasive, or it will almost certainly mark the glass. When painting windows and doors it is sometimes confusing to the inexperienced person which parts of the windows or doors, and their frames, should be painted with the interior colour, and which surfaces should be coated with the outside paint. As a general rule it may be assumed that all surfaces visible from the inside are coated with the interior paint.

Window-frames should be cleaned down in the same way as the picture rail, using plenty of elbow grease with the glass-paper and dusting all surfaces before carrying on with the next part of the job, which is the door. Where it is possible with windows and doors, it is advisable to remove the furniture before commencing work. The furniture is, of course, door-knobs, rim-locks, finger-plates and any other metal fittings, including sash fasteners and casement stays and handles. These may be left in position if removal is inconvenient, but this will entail a lot of extra work in cutting cleanly round their edges. Finish the preparation of paintwork with the skirting boards.

After cleaning down, the next job to be done is coating of any knots that have been bared when cleaning down, or coating of knots which have not been previously treated and from which resin has exuded through the old paintwork. Bare or new wood should be primed and any cracks or nail-holes should be touched in with priming paint, or this can be done with knotting. If there is no new or bare wood to prime, the use of knotting, which is fast-drying, for sealing inner surfaces of holes will speed up the work at this stage. If the work has been primed it should be left for about 24 hours to allow the paint to harden, when this first coat should be rubbed down with glass-paper before filling and stopping holes and cracks with glazier’s putty, or patent powder-filler, or a combination of both. Powder-fillers are difficult to finish in gaps at the corner of mouldings. Whatever type of stopping is used it should be pressed well into the hole or crevice to completely fill it — it is bad practice merely to fill the top of the repair, leaving a void behind. Puttied fillings may be finished by smoothing them with a dusting-brush. Powder-filler should of course be left to harden before finishing by cutting it down level with the surrounding surface with glass-paper.

With all the holes and crevices stopped or filled, the work should be gone over with a duster to clean it before applying the first undercoating. The undercoat is applied in the same sequence as the preparatory work, starting at the top of the room and working down to finish with the skirting-board. The colour of the undercoating should be in sympathy with the colour of the finishing coat of paint. In most cases it will be advisable to apply two undercoats; the first coat should be allowed to dry before the second coat is applied, and the work is rubbed down and dusted before every coat is applied. In some cases the second undercoat may be eliminated for inside work, but this should only be done when the condition of the surface is exceptionally good. The second undercoat may be mixed with some finishing paint to prepare a good basis for the final coat. A sensible proportion is 50 per cent of each. The final undercoat after drying should be sanded down before applying the finishing coat and each coat of paint should be allowed to dry thoroughly before the next one is applied. Sanding of the final undercoat is best done with the pieces of worn glass-paper used in the initial stages of preparing the surfaces. The finishing coat is applied in the same way as the undercoating, using a clean brush, and the last part of the job consists of replacing metal fittings to doors and windows.

If it is necessary to thin any coats of paint this should be done according to container instructions, using only the thinners specified. Most types of primers and undercoatings can be thinned with turpentine or substitute turps. Aluminium priming coat should not require thinning if it is kept stirred when it is applied, but should there be any thick deposit at the bottom of the tin this may be revived by thinning with a little methylated spirit. There is one very important feature of preparation which even professionals sometimes overlook, and this is the thorough stirring of the paint. It is essential to thoroughly activate the pigments in the medium and it takes at least 10 minutes to really stir a tin of paint. The best thing to use is a piece of wood, the end of which should be sharpened to a wedge shape. This should be worked in a circular movement until the bottom of the tin feels clean and continued stirring should be carried on for some minutes after the bottom of the tin has been cleaned by the stick used for stirring. If the job is a long one involving a great deal of time-in cutting in, particularly with windows with small squared panes, the paint should again be stirred as the job progresses. If this is not done the full benefit of the paint will not be obtained and the worker will merely brush on a partly loaded medium, the main body of the pigments remaining at the bottom of the tin out of reach of the brush.

24. July 2011 by admin
Categories: Painting | Tags: , | Comments Off on DIY Method of Painting and Preparation


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