Ingredients of a distemper
A distemper is composed of base, carrier, colouring pigments and size. For base, the whiting or chalk is used and for carrier, the water is used. Thus it is more or less a paint in which whisking or chalk is used as base instead of white lead and the water is used as carrier instead of linseed oil.
The distempers are available in powder form or paste form. They are to be mixed with hot water before use. The oil-bound distempers are a variety of an oil paint in which the drying oil is so treated that it mines with water. The emulsifying agent which is commonly used is glue or casein. As the water dries, the oil makes a hard surface which is washable.
It should be remembered that most of the manufacturers of ready-made distempers supply complete directions for use of their products. These directions are to be strictly followed to achieve good results.
Process of distempering
The application of distemper is carried out in the following way:
(1) Preparation of surface: The surface to receive the distemper is thoroughly rubbed and cleaned. The important facts to be kept in mind are:
(i) The new plastered surfaces should be kept exposed for a period of two months or so to dry out before distemper is applied on them. The presence of dampness on the surface results in failure of distemper coating
(ii) The surface to receive distemper should be free from any effloresce patches. These are to be wiped out by clean cloth.
(iii) The irregularities such as cracks, holes, etc. of the surface are to be filled by lime putty or gypsum and allowed to become hard before distemper is applied on the surface.
(iv) If distemper is to be applied on the existing distempered surfaces, the old distemper should be removed by profuse watering.
(2) Priming cost: After preparing the surface to receive the coats of distemper, a priming coat is applied and it is allowed to become dry. For ready-made distempers, the priming cost should be composed of materials as recommended by the makers of distempers. Local made distempers, the milk is used for priming coat. One litre of milk will cover about 10 m2 of the surface.
(3) Coats of distemper: The first coat of distemper is then applied on the surface. It should be of a light tint and applied with great care. The second coat of distemper is applied after the first coat has dried and become hard.
Following facts are to be remembered:
(i) The distempering should be done in dry weather to achieve better results.
(ii) The oil-bound distemper or washable distemper adheres well to ail- painted walls, wood, and corrugated iron. Etc. But a priming coat of pure milk should be applied before distempering is done on such surfaces.
(iii) The application of distemper by a spraying pistol is superior to that by brushes. The spraying affords smooth and durable film of distemper.
PD Consulting Engineers Pvt. Ltd. Transforming construction for a new generation "Cost, Quality & Project management"
QS & Cost management, Bill Checking / Audit, Technical Auditors, Valuation, Contract and Tendering, Project Management, Project Planning, Quality Control, Consulting Engineers, Structural Consultancy
Civil N Construction Blog