If the old paint work is in a perished or cracked condition, no satisfactory job can be made other than by complete removal of the old film.
Old work can also be cleaned with lime-wash and rubbed with pumice, filling all holes with putty. Washing with soap and water is also effective.
Sodium Carbonate or Washing Soda : Diluted with water is the cleansing agent used in the preparation of old painted surfaces for repainting. Cleanses greases and fats.
Paint Removers
Ready made paint removers are available.
2 parts quick-lime, 1 part washing soda made to the consistency of cream is painted over the wood.
Thick layers of old paints are generally burnt with a blow lamp and scrapped. Flame of blow lamp cracks window glasses for which precautions must be taken.
French Polish
French Polish is a spirit varnish and is made by dissolving ¼ kg of shellac in ½ litre of methylated spirit or naphtha and straining the solution through a double thickness of coarse muslin. A number of other recipes are also in use. It should be applied to the prepared wood surface with a polishing pad of soft cloth containing absorbent cotton filling, and not with a brush, with quick and light strokes along the grain. Several coats will be necessary before the desired shine and finish is achieved. The pad may be dabbed with a drop of olive or mustard oil after each coat to allow a smooth working and finish. The wood to be polished should be first painted with filler composed of 3 kg of whiting mixed in 3 liters of methylated spirit and then sandpapered when dried.
Fillers can also be made as follows :
a) Whiting mixed with water
b) Linseed oil and bees wax (3:1) boiled
c) Plaster of Paris either in water or raw linseed oil
French polish is worked upon the surface of hardwoods to heighten the effect of the grain.
Frequent application of raw linseed oil rubbed in well with rags will give a very fine polish to the woodwork.
A good furniture polish can be made of equal parts of vinegar and linseed oil, or better still of vinegar and olive oil in the same proportions, as this mixture is less sticky than the former.
Wax Polishing
Wax polish is made by mixing 2 parts of bees wax with 2 parts of boiled linseed oil over a slow fire, when dissolved but still warm, add one part of turpentine. Smear the woodwork with the mixture and after 24 hours rub with a soft flannel to a fine polish. Wax polishing is mostly used for polishing cement concrete floors.
Whitening
Whitening mixed with size and water is used for whitening ceiling and walls. Whiting is made by reducing pure white chalk to a fine powder.
Varnishing
The woodwork when prepared should be sized with a coat of thin clear glue to which a little brown earth and ochre should be added if the wood is of oily nature and the varnish does not readily dry from this cause. This should be applied hot and rubbed down smooth. A second coat of thin clean glue with necessary quantity of staining colour consisting of equal parts of burnt umber and burnt sienia should then be applied, allowed to dry and rubbed down smooth with fine sand-paper. Two coats of boiled linseed oil can be given instead of glue size. Varnish should be laid on in thin coats over this when dried. English Copal varnish is considered best. For new woodwork a second coat of varnish should be applied after the first coats has thoroughly dried and rubbed down with fine sand-paper before the first coat and after each coat of varnish except the last. One kg of glue makes about 10 liters of size.
The varnish should become surface dry in not more than 6 to 8 hours and hard dry in not more than 18 hours. ½ liter of varnish will cover about 15 sq. m of surface, single coat. Good varnish should be dry and free from stickiness within 2 days. Varnish and painting should be avoided on stormy and rainy days. Varnishing is generally prescribed for interior works and painting for exposed prescribed for interior works and painting for exposed positions.
Oiling Woodwork
One kg of beas wax mixed with 3 kg of double boiled linseed oil are heated over a slow fire till the wax is melted. After the mixture has cooled, ¾ liter of turpentine is added. This will cover about 150 sq.m. of surface. The woodwork can also be oiled with country sweet oil to which equal parts of vinegar and turpentine have been added. This gives a darker effect. A mixture of oil and water should never be used.
Only well-seasoned wood should be painted or oiled. Painting damp or unseasoned wood will do more harm than good and will only induce dry rot and also result in the paint blistering.
