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| Raw material recommended for painting of metal surface:
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| PRIMER :
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There are two types of primers used for metal surfaces:
Red oxide zinc chromate
zinc chromate
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Red oxide zinc chromate primer shall be used for iron and steel work including galvanized steel.
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Zinc chromate primer shall be used for painting aluminum and light alloys and may be used for steel works.
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Covering capacity is about 18 to 20 sq m/liter/coat
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Where primer for steel work is specified to be mixed at the spot, it shall be prepared from a mixture of red lead, raw linseed oil and turpentine in ratio of 2.8 kg: 1 liter: 1 liter
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| RED LEAD COATING :
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This should be in powder form, pure, free from adulteration like brick dust etc.
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| RAW LINSEED OIL COATING :
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It shall be lightly viscous but clear of yellowish color with light brown tinge. The oil shall be smooth and sweet to the taste with very little smell. The oil shall be of sufficiently matured quality. Oil turbid or thick, with acid and bitter taste and rancid odor and which remains sticky for a considerable time shall be rejected.
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| DOUBLE-BOILED LINSEED OIL COATING :
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This shall be more viscous than the raw oil, Have deeper color and specific gravity between 0.931 and 0.945 at a temperature of 30 degree Celsius. It shall be dry with a glossy surface. The oil shall be approved brand and manufacture.
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| TURPENTINE :
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Mineral turpentine, i.e., petroleum distillate that has the same rate of evaporation as vegetable turpentine shall be used. It shall have no grease or other residue when allowed to evaporate.
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| EETERIOR GRADE ENAMEL PAINT :
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These are available in two types:
Synthetic enamel
Enamel
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Synthetic enamel becomes surface dry much faster than enamel paints.
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Covering capacity of synthetic enamel paints for painting metal surfaces is about 15-22 sqm/liter for single coat and 10-12 sq m/liter for two coats.
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For undercoat, paint of the same quality shall be used. The best coating for metals (fencing, window grills, fans, gates, poles, etc.) is provided by synthetic enamel paint, which acts both as a decorative and protective coating.
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Enamels are tough, durable and protect metals from corrosion. On drying, they form a smooth glossy, relatively hard and permanent solid layer. The enamel paint coat presents a glossy surface but, if desired, an eggshell or flat finish may also be obtained by adding turpentine in small quantity.
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| NOTE: Ready mixed paints have the correct consistency and shall not require further dilution by addition of thinners. If a slight adjustment of viscosity is necessary, use the thinner recommended by the manufacturer.
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| ENAMEL PAINT, INTERIOR :
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These paints are used for the interior protection and decoration.
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| RED OXIDE PAINT :
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It shall be prepared by mixing red oxide, raw linseed oil and boiled linseed oil in the ratio of 4.79 kg: 2 liter: 1 liter. This paint is recommended where red colour is acceptable.
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