Paints and varnishes are used to protect metals, timber or plastered surfaces from the corrosive effects of weather, heat, moisuture or gases etc. and also to improve their appearance.
Paints and Varnishes
Paints and varnishes
CLASSIFICATION
Paints in common use are classified as oil paints, water paints, cement paints and bituminous paints. There are some “special paints” used for special purposes e.g. heat resisting or fireproof paints, chlorinated rubber paints (for protection against acid fumes etc.) luminous paints (for visibility of painted surfaces in the dark) etc., etc.
VARNISH
Varnish is solution of resin in either oil of turpentine or alcohol. It dries after applying leaving a hard, transparent and a glossy film of resin over the varnished surface.
Varnish is applied : (i) to the painted surface to increase its brilliance and to protect it from the atmospheric action, (ii) to the unpainted wooden surface with a view to brighten the ornamental appearance of the grains of wood.
Learn : Repainting wood work,Repainting Wood Furniture,Repainting Doors,Repainting Cabinetry,wood floors Repainting wood work (i) If the old paint be unsightly, unsound, blistering or flaking off then it should be removed by the application of some paint remover, by scrapping or by burning the paint with a blow lamp. (ii) On surface disfigured by smoke a coat of one kilogram glue and 60 gms of unslaked lime in four kilograms of water should first be given. (iii) The surface should be thoroughly cleaned by washing it with soap and water. All greasy spots should be painted with turpentine oil and washed with soap and water. A solution of washing soda in water is used for cleaning the surface of all greasy spots. (iv) All holes and cracks etc. should be filled up with putty i.e. stopping should be done. (v) Before the application of each coat the surface should be rubbed smooth…
Learn : Painting plastered surfaces,New plastered surfaces Painting plastered surfaces (i) A plastered surface should be painted only after it has thoroughly dried, otherwise the paint would get spoil. (ii) To avoid sucking of paint by plaster soak the surface with a pore filling solution which will dry off leaving an impervious surface. A wash of 1 kg of size, 500 gm of soft soap and 9 liters of creamy lime wash is recommended. (iii) Cracks or holes, if any, should be filled in with glaziers putty and the surface sand papered on its drying. (iv) First two coats should consists of white lead and boiled linseed oil. (v) Third coat should consist of white lead, linseed oil, desired pigment and a little turpentine oil. This coat is applied after the surface has been rubbed smooth. Finishing coat having the same composition as the third coat but having more of…
Learn : Painting new wood work : Knotting or killing the knot, Application of priming coat, Stopping, Application of finishing coats. Painting new wood work Following points should be attended to before painting new wood work: (i) Only well seasoned timber should be painted otherwise not only shall the paint be spoilt but also due to dry rot the timber is likely to decay early. Also the paint surface will otherwise crack due to uneven shrinkage (ii) It is advisable not to paint excessively dry wood. (iii) Paint should be applied to only dry surface. (iv) The surface to be painted should be rendered smooth, clean and free from rust or dirt. (v) All nails should be punched in 1/2 cm below the surface. (vi) Large and loose knots should be cut out and filled tightly with correctly fitting wooden pieces. (vii) The surface should be…
Learn : Removal of old paint and painting : Remove the paint, old paint and painting Removal of old paint and painting REMOVAL OF OLD PAINT One of the following two methods could be employed to remove old paint from a surface : (i) Burning the paint by directing the flame of a blow lamp on the painted surface and scrapping it. The method is quite suitable, quick and economical in case of iron or steel work but only expert workmen could be depended upon for its use in case of wood work. A little carelessness could leave the wood charred. (ii) Applying any one of the following paint removers : (a) Hot solution of equal parts of soap, potash and quick lime is applied on the surface and kept on it for 24 hours, after which washing with hot water will remove the paint. (b) Two parts of quicklime and…
Learn :Preparation of oil paints Learn : Composition of oil paint PREPARATION OF OIL PAINTS. To get started making oil paint, you’ll need: 1) Cold-pressed, raw, or unrefined linseed oil – Linseed oil tends to do much of the heavy lifting in many oil based paint formulations. The reason is that unlike most plant based oils, linseed oil is known as a drying oil. For example, if you were to spill some olive oil on your counter top, chances are it would still be wet to the touch many weeks later. Linseed oil is different in that if you were to spill some on your counter, it would dry to form a tough film within a few days. While you’ll be able to find linseed oil at most artist supply shops, you can also find it at the grocery store as flax seed oil. Despite what the fancy artist paint brands…
Learn : Characteristics of a good paint,Paints, Paints Classification Characteristics of a good paint Paints Paints are used to protect metals, timber or plastered surfaces from the corrosive effects of weather, heat, moisture or gases etc. and also to improve their appearance. Paints Classification Paints in common use are classified as oil paints, water paints, cement paints and bituminous paints. There are some "special paints" used for special purposes e.g. heat resisting or fireproof paints, chlorinated rubber paints (for protection against acid fumes etc.) luminous paints (for visibility of painted surfaces in the dark) etc., etc. Characteristics Following are the Characteristics of a good paint: (i) It should have a good body or spreading power. (ii) It should work smoothly and freely and be capable of being laid in a thin coat with the brush. (iii) It should form durable, tough and resistant to wear film on drying. (iv) …
Learn :Composition of oil paints: Base: White lead, Red lead, Zinc oxide (or zinc white), Iron Oxide, and metallic powders such as Aluminum, Copper and Bronze etc. are the commonly used bases,Vehicle: Oils most commonly used as vehicles are : Linseed oil, Poppy oil. Nut oil and Tung oil. Colouring pigments,Solvent or thinner,Drier,Inert filler Composition of oil paints Oil paints consist essentially of – (i) a base, (ii) a vehicle (always an oil, generally raw or boiled linseed oil), and (iii) one or more colouring pigments. It may also contain one or more of (iv) a solvent or thinner, (v) a drier, and (vi) an inert filler. By suitable variation of the type and proportion of the various constituents the paints can be made dry, glossy or flat as desired. Other properties such as permeability to water could also be varied accordingly. All the possible constituents of paints are described in…
