CE_Painting civil engineering course of 2nd

1. 1
INTERIOR FINISHING
It consists of painting, distempering and white washing
Paints are liquid compositions of pigments and binders
which when applied to the surface in thin coats dry to
form a solid film to impart the surface a decorative finish
and giving protection from weathering, corrosion and
other chemical and biological attacks.

2. 2
PAINT
Characteristics of an ideal paint:
 It should form hard and durable surface.
 It should give attractive appearance.
 It should be cheap and readily available.
 It should be such that it can be applied easily to the
surfaces.
 It should have good spreading property.
 It should dry in reasonable period.
 It should not show hair cracks on drying.
 It should form film of uniform color on drying.
 It should be stable for longer period.
 It should not be affected by atmospheric agencies

3. 3
Constituents of paint
1.Base: A base is a solid substance in a form of fine powder,
forming the bulk of paint. It provides of opaque coating to hide
the surface to be painted.
2.Vehicle: The liquid substances which hold the different
ingredients of paint in liquid suspension. The vehicle makes it
possible to spread the paint evenly on the surface.
3.Drier: Accelerate the process of drying and hardening by
extracting oxygen from the atmospheric and transferring it to
the vehicle.
4.Colouring pigments: added to the base to desired colours.
5.Solvent or thickness: added to the paint to make it thin so
that it can be easily applied on surfaces. It also helps the paint
in penetrating through the porous surface of the background.
PAINT

4. 4
Based on Binders:
a) Oil paints
b) Paints based on non oil resins
c) Cellulose paints
d) Water based paints
e) Miscellaneous paints
Based on ultimate use:
a)General purpose paints including prime coat and
finishing coat paints.
b)Acid and alkali resistant paints.
c)Fire resistant paints.
d)Fungicidal paints.
e)Miscellaneous paints such as fire resistant paint,
anti condensation paint etc.
CLASSIFICATION OF PAINT

5. 5
Mixed classification
a) Aluminum paints
b) Anti corrosive paints
c) Asbestos paints
d) Bituminous paint
e) Bronze paints
f) Casein paints
n) Plastic paints
o) Silicate paints
p) Synthetic rubber paint
g) Cellulose paints
h) Colloidal paints
i) Cement based paints
j) Emulsion paints
k) Enamel paints
l) Graphite paints
m) Oil paints
CLASSIFICATION OF PAINT

6. 6
Painting on new wood work:
 Preparation of surface: For good results
wood work should be well seasoned and
should not contain more than 15% moisture.
Dust is totally removed from the surface.
 Knotting: Knotting is the process of
covering or killing all knots in the wood
work with a substance through which the
resin cannot come out.
 Priming: After knotting, the surface is
lightly rubbed smooth with a abrasive paper.
Priming consists of applying first coat of
paint to fill all the pores.
PAINTING OF SURFACE

7. 7
Painting on new wood work:
 Stopping: It is the process of rubbing down the wood
surface by means of glass paper after prime coat is
applied and then filling up all cracks, all nail holes,
open joints with putty. After putty dries up, the surface
is rubbed again with glass paper.
 Under coating: After stopping second and successive
coatings are applied. This is known as under coating.
This coat serves as foundation to the finish coat.
 Finishing coat: Finishing coat is applied after the
under coat is perfectly dry. This coat is applied very
carefully so that finished surface is smooth, uniform
and free from patches.
PAINTING OF SURFACE

8. 8
Repainting old wood work:
Before repairing old wood work, the old paint having
cracks and blisters should be removed by applying 1kg
of caustic soda in 5litres of water. Then the old paints
get dissolved.
After removing the old paint, the surface is properly
cleaned and rubbed with glass paper. The cleaned
surface is then given two or three coats of paint.
PAINTING OF SURFACE

9. 9
Painting new iron and steel work:
Iron and steel surface are painted so that rusting is
prevented. The process is:
 Scale and rust on the surface removed by scrapping
or brushing with wire steel brush. Oil grease etc are
removed by washing with petrol, benzene or lime.
 The cleaned surface is treated with a film of
phosphoric acid. It protects the surface from rusting.
 The prime or first coat is then applied.
 After the prime coat has dried, two or more under
coats are applied with a brush or spray gun
 After that the final coat of the desired type of paint
is applied.
PAINTING OF SURFACE

10. 10
Repainting old iron and steel work:
 Before repainting, the old surface is thoroughly
cleaned by soap water.
 The grease may be cleaned by washing the surface
with lime and water.
 However if the old paint has cracked, it has to be
removed by flame cleaning.
 The surface is then scrapped with wire brush and
washed with solution of caustic soda and fresh
slaked lime.
 After the surface is prepared, painting is carried out
as for new surface.
PAINTING OF SURFACE

11. 11
Painting plastered surface:
 Newly plastered surface may contain considerable
moisture. Hence painting should be restore to after 3to 6
months of plastering.
 Calcareous surface like lime or cement plastered
surfaces are highly alkaline because lime is liberated
during hydration of cement.
 Due to this, oil based paints and distempers are liable to
alkali resistant primer. Absorption of liquid from paint
is known as suction. High suction may make the paint
difficult to apply and leave the coating in an under
bound condition.
 If the surfaces show high suction, it should be treated
with suitable primer.
PAINTING OF SURFACE

12. 12
Distempering:
Distempers are considered as water paints. Distemper is
composed of a base such as whiting or chalk, a carrier as
water, a binder as glue and coloring agent i.e. coloring
pigments.
Process of distempering:
Preparation of surface: The surface to be distempered
should be thoroughly rubbed and cleaned. The
efflorescence patches should be carefully wiped out by
clean cloth. The irregularities in surface should be filled
with putty.
DISTEMPERING

13. 13
Process of distempering:
 For new surface it should be kept exposed for 3to
6months so that all the moisture evaporates. For old
surface, old loose distemper should be removed by
scrapping. New cement plaster surface should be
washed with solution of zinc sulphate in water and
allowed to dry.
 Prime coat: After cleaning the prepared surface,
priming coat should be applied. For readymade
distempers, prime coat as suggested by the
manufacturer.
 Coats of distempers: Distempers are applied in 2to3
coats and subsequent coat apply after dried up previous
one
DISTEMPERING