30‐Sep‐20
Unit: 8 PAINTS AND VARNISHES
ER. KRISHNA NIR CHHUKAN
INSTRUCTOR
TECS PROGRAMME
BAGISWORI HIGHER SEC. SCHOOL
03 AUG 2016
OVERVIEW
8.1 INTRODUCTION – PAINTS AND VARNISHES
8.2 USES OF PAINTS AND VARNISHES
8.3 TYPES OF PAINTS
8.4 COMPOSITION OF VARIOUS TYPES OF PAINTS: OIL
PAINT, WATER PAINT, CEMENT PAINTS AND
ACRYLIC PAINTS
8.5 PREPARATION TECHNIQUES OF VARIOUS PAINTS
8.6 METHODS OF APPLICATION ON VARIOUS
CONSTRUCTION LOCATIONS
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30‐Sep‐20
8.1 INTRODUCTION – PAINTS AND VARNISHES
Paint is a liquid surface coating. On drying it forms a thin film (60–150 )
on the painted surface.
Paints are classified as oil paints, water paints, cement paints, bituminous
ppaints and special
p paints
p such as fire proof
p paints,
p , luminous ppaints,,
chlorinated rubber paints (for protecting objects against acid fumes), etc.
8.1 INTRODUCTION – PAINTS AND VARNISHES
Varnish is a nearly homogeneous solution of resin in oil,
alcohol or turpentine. The type of solvent depends upon the
type of resin used
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8.2 USES OF PAINTS AND VARNISHES
To paint on wooden surface.
To paint on metallic surface.
T paint
To i t on Machine
M hi parts. t
To varnish on finishing surface of wood.
8.3 TYPES OF PAINTS
1. Oil Paint
2. Water color paint
p
3. Acrylic paint
4. Cement paint
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Oil Paint
Easily mixed, more permanent, used
after 1400, slow-drying, can be used in
thi layers
thin l called
ll d glazes
l or iin thi
thickk
lumps to make an impasto surface.
Watercolor (Aquarelle)
Most common water-based paint,
transparent. White paint is seldom used to
lighten paint (water is used ) Light colors
are applied first, then dark, working from
background to foreground.
http://www.artlex.c
om/ArtLex/wxyz/w
atercolor.html
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Acrylic Paint
Synthetic paint with plastic binder
Recent (20th century), versatile, similar to
oil but dries faster, not as shiny
http://www.artlex.com/ArtLex/a/acrylicpaints.html
Cement Paint
Cement paints: (IS 5410) White or coloured Portland
cement with (OPC minimum 65
pper cent)) forms the base. Theyy are thinned with water
during application. Proper curing is
necessary for strength and durability.
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8.4 COMPOSITION OF VARIOUS TYPES OF PAINTS:
OIL PAINT, WATER PAINT, CEMENT PAINTS AND
ACRYLIC PAINTS
a) Base
b) Inert extender or filler
c) Vehicle
d) Drier
e) Solvent or thinner
f) Coloring pigment
8.4 COMPOSITION OF VARIOUS TYPES OF PAINTS:
OIL PAINT, WATER PAINT, CEMENT PAINTS AND
ACRYLIC PAINTS
a) Base
The base, usually a metallic oxide,
is the principal constituent of the paint. It makes the
paint film opaque and possesses binding properties
which reduce the shrinkage cracks in the film on drying.
Some of the examples
of base are white lead, red lead, zinc white,
aluminium
l i i powder,
d iron
i oxide,
id etc.
t
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8.4 COMPOSITION OF VARIOUS TYPES OF PAINTS:
OIL PAINT, WATER PAINT, CEMENT PAINTS AND
ACRYLIC PAINTS
b) Inert extender or filler
Adultrants or inert extender or filler brings down
the overall cost,
reduce the weight and increase the durability.
Adultrants also help to reduce cracking of dry paint
and sometimes help to keep the pigment in suspension
suspension.
Barium sulphate, calcium carbonate, magnesium silicate and
silica are but a few examples.
8.4 COMPOSITION OF VARIOUS TYPES OF PAINTS:
OIL PAINT, WATER PAINT, CEMENT PAINTS AND
ACRYLIC PAINTS
c) Vehicle
Vehicle is the liquid substance which holds solid
ingredients of paints. It acts as binder between
base and pigment. The main purpose of the vehicle
is to adjust the viscosity of the paint. It is volatile and
does not become part of the paint film. It can also control
flow and application properties, and affect the stability of
th paint
the i t while
hil iin liliquid
id state.
t t
For example: Linseed oil, nut oil, puppy oil, tung oil etc.
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30‐Sep‐20
8.4 COMPOSITION OF VARIOUS TYPES OF PAINTS:
OIL PAINT, WATER PAINT, CEMENT PAINTS AND
ACRYLIC PAINTS
d)) Drier
It is also known as plasticizers, are chemicals
added to paint for specific purposes, e.g., as
catalyst (accelerate the drying of the vehicle) for the
oxidation, Polymerisation and condensation of the
vehicle in paint.
8.4 COMPOSITION OF VARIOUS TYPES OF PAINTS:
OIL PAINT, WATER PAINT, CEMENT PAINTS AND
ACRYLIC PAINTS
e) Solvent or thinner
Solvents are the oils used to thin the paints,
increase the spread, and are also known as thinners.
They make the paint of workable consistency and
evaporate during drying of the film.
The common thinning agents used are
petroleum, spirit, naptha and turpentine oil
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30‐Sep‐20
8.4 COMPOSITION OF VARIOUS TYPES OF PAINTS:
OIL PAINT, WATER PAINT, CEMENT PAINTS AND
ACRYLIC PAINTS
f) Coloring pigment
Pigments
g are g
granular solids incorporated
p into
the paint to contribute colour, toughness or simply
to reduce the cost of the paint.
Some of the examples of pigments used to produce
the desired colours are:
•Blue: Prussian blue, indigo, cobalt blue, ultramarine blue.
•Black: lamp black,
black ivory black,
black graphite,
graphite vegetable black.
black
•Brown: burnt umber, burnt siena, raw umber.
•Yellow: chrome yellow, yellow orchre, raw siena, zinc
•chromate, barium chromate.
• Red: vermilion red, red lead, carmine, Indian red and vexetian red.
•Green: Copper sulphate, chrome green, green earth, cmerals green.
8.5 PREPARATION
TECHNIQUES OF
VARIOUS PAINTS
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30‐Sep‐20
8.6 METHODS OF APPLICATION ON VARIOUS
CONSTRUCTION LOCATIONS
Surface Preparation:
Before applying the paint it is ensured that the surface is free from dust, dirt, loose
matter, grease etc. and is rubbed with an emery paper, to provide a mechanical key
between surface and paint for satisfactory adhesion.
adhesion
Sequence of painting :
The primer (first coat) is applied with brush or spray on the prepared surface. It
should be thinned with water or thinner in the recommended manner and
proportion before application. After drying it is rubbed with
emery paper.
Dents and cracks, if any, are filled with putty
usingg a knife applicator.
pp Puttyy should not be
applied thick. If the required thickness is large,
it should be applied in two coats. After the
putty has dried, the whole surface is rubbed
down well in order to smoothen the putty and
provide a mechanical key to the finished coats.
Two or three finish coats are applied. Each coat
is allowed to dry before the application of next
coat.
THANK YOU
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