paint-
Paints are surface coatings, generally suitable for site use and marketed in
liquid form. The may be used for one or more of the following purposes.-To
protect the underlying surface by exclusion of atmosphere, moisture, fungi and
insects.1 To provide a decorative easily maintained surface.2 To
provide light and heat reflecting properties.3 To give special effects; e.g.
inhibitive paint for protection of metals, electically conductive paints as a
source of heat, condensation resisting paints, etc. Painting systesm – There are three stages in a painting
system – primer, undercoat and finishing coat. Primingcoat and undercoat do not
provide an impermeable dirt-resistant coating Primer – The fubction of the primer is to grip the
substrate, to provide protection against corrossion / dampness and to provide a
good key for remaining coats.
Undercoat – The function of the undercoat is to provide good opacity
(hiding power) together with a smooth surface which provides a good key for
fininshing coat. Undercoats usualyy contain large quantities of pigments to
provide opacity. Finishing coat
– This provides a durable layer of the required colour and texture.
Traditionally, most finishing coats were gloss and it tend to have the
resistance to dirt since they provide very smooth surface. However, some paint
types such as emulsion will not normally give the high gloss of traditional oil
paint
Special paints.Oils
paint- Oilssuch as teak oil are used mainly
for internal applications exterior use are high in solids producing an
ultraviolet resistant, micro-porous finish which may be transparent or opaque.
The finish, which should not flake or crack, may be renovated by the
application of a further coat3 water
profinpaint-Waterproof paints and coatings can be applied by either a
actor or homeowner. When applied correctly, it coats the walls with will
quickly blister and flake off the basement walls, creating a mess. ...
Waterproof paint is an easy-to-use, inexpensive product that a barrierthat's
meant to hold back waterand moisture4Emulsion
paint-is themostcommonly used paint for interior walls and ceilings and
there are three main types of finishes you need to know about. Vinyl matt adhesion
These paints have the advantage of being water-miscible. On drying out,
coalescence of polymer particles occurs, resulting in a coherent film with
moderate resistance to water.Bituminous
Paints - are made of asphalt bitumen dissolved in mineral spirit or
naphtha. They are black in colour,
Enamel Paints - Enamel paintsbased on polyurethane or alkyd resins give
highly durable impact-resistant easily cleaned hard gloss surfaces. Colours
tend to be strong and bright, suitable for machinery and plant in interior and exterior
locations wall or ceiling.Heat
Resisting Paint - Aluminium paint,
which has a glossy metallic finish, is resistant microns is typical.
Acrylated to temperatures up to 230contr- 260°C. A dry-film thickness of 15
rubber paints can usually be used satisfactorily to100°C.5Propertis of good paint-1•Wearability:2
Paint must be resistant to the wear and tear of the atmosphere and should
maintain its color, smoothness and fi nish for a long •Covering ability: ...
time. ... •Environmentally Friendly: ..5 Aesthetic: •Practical and cost
effective. Painting SpecificMaterials
-1Ferrous metals like iron and steel can oxidize to form rust. This
weakens the metal and can cause failure of the part. To avoid rust and
corrosion, a variety of different coatings can be applied to the metal.
Coatings are designed to prevent oxidation by keeping the paint. Non-Ferrous Metals – Zinc and
aluminium are the non-ferrous metals most likely to require surface coatings
and each provides a poor key for paint, unless surface trearment is first
carried out. Zinc reacts with most oilbased paints, COMMON DEFECTS AND REMEDIES IN PAINTING. An Architect
Explains. Blistering: Blistering or Swelling of paint is caused due to the
trapping of air, moisture or solvent between the surface and the paint film.
The Solution– Remove any unstable paint films and allow the wall to dry
thoroughly ing soluble salts which reduce
CONSTITUENTS OF PAINTS: 1. Pigments Pigments are various inorganic or
organic insoluble substances which are widely used in surface coatings. The
most important properties of pigments are opacity, good covering power, mixing
ability with oil, chemical inertness, non toxicity or low toxicity, high hiding
power, high tinting strength and reasonable cost
Lime-
is a calcium-containing inorganic mineral composed primarily of oxides, and
hydroxide, usually calcium oxide and/ or calcium hydroxide. It is also the name
for calcium oxide which occurs as a product of coal seam fires and in altered
limestone xenoliths in volcanic ejecta. The word lime originates with its
earliest use as building mortar and has the sense of sticking or adhering.
These materials are still used in large quantities as building and engineering
materials
Manufacture of Lime-
The manufacturing of the lime is done by following the process of collection of
the lime stones, calcination of the limestone, and then slaking of the
limestone. Lime is of the three types. It is fat lime, hydraulic lime and the
poor lime. If we have to prepare the fat lime then the quality of the limestone
should be such that it contains about 90 to 95% of the limestone and should
contain less than 5% of the impurities.Calcium carbonate (limestone) is turned
into calcium oxide (quick lime) by heating. This dissolves to form calcium
hydroxide (slaked lime) which can be used to test for carbon dioxide if it is
dissolved in water to make limewater. When testing for carbon dioxide, you
produce calcium carbonate which causes the milky colour and completing the
cycle.

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