2. PAINT
It is any pigmented liquid, liquefiable, or mastic composition
that, after application to a substrate to a thin layer, converts
to a solid film.
It is used to protect metals, timber, plastered surfaces, brick
work, concrete work from the corrosive effects of weather,
heat, moisture or gases etc and to improve their appearance.
3. COMPOSITION OF PAINTS
It contains:
A base which provides body
A carrier in which base is dissolved
A pigment to add desired colour
Commonly used bases are zinc white, white lead, red lead.
Commonly used carrier are water, linseed oil, poppy oil.
4. PROPERTIES OF GOOD PAINT
It should give uniform and thin coating.
It should be hard and durable on drying.
It should be water-repellent.
It should have good spread.
It should have good adhesive power.
The colour should be fast and permanent.
It should be cheap and economical.
It should be resistant to weathering and corrosive action.
5. CLASSIFICATION OF PAINTS
OIL PAINTS
For painting wooden and metallic surfaces.
Carriers used are linseed oil, poppy oil, castor oil.
To obtain good results, two to three coatings are
needed.
6. PLASTIC PAINT
It contains the requisite amount of plastic.
They are used wherever high class work is required, such
as sophisticated buildings, show rooms, theatres and
auditoriums.
WATER PAINT
It contains water as a carrier.
Casein is most common binder
These are cheap, easily workable.
7. BITUMINOUS PAINT
Prepared by dissolving bitumen in petroleum or other
solvent oil.
These black coloured paints leave hard, tough and elastic
surfaces.
Highly resistant to water.
Used for submerged iron and steel structures.
8. Varnishes
Varnish is a clear transparent hard protective finish or
film. Varnish has little or no color and has no added
pigment as opposed to paint or wood stain which
contains pigment.
9. Components of varnish
Drying oil
There are many types of drying oils, including linseed
oil, tung oil, and walnut oil. These contain high levels of
polyunsaturated fatty acids.
Resin
Resins that are used in varnishes include amber,
dammar, copal, rosin (pine resin), sandarac, balsam, and
others.
10. Turpentine or solvent
Traditionally, natural (organic) turpentine was used as the
thinner or solvent, but has been replaced by several mineral
based turpentine substitutes such as white spirit or "paint
thinner."
11. Types
Violin
For violin varnish, walnut oil and linseed oil are most
often used in combination with amber, copal, rosin or
other resins. The oil is prepared by cooking or exposing
to air and sunlight. The refined resin is typically available
as a translucent solid and is then "run" by cooking or
literally melting it in a pot over heat without solvents.
12. Resin
Most resin or "gum" varnishes consist of a natural, plant- or
insect-derived substance dissolved in a solvent. The two
main types of natural varnishes are spirit varnish (which
uses alcohol as a solvent) and turpentine or petroleum-
based varnish.
Shellac
Shellac is a very widely used single component resin varnish
that is alcohol soluble. It is not used outdoors or where it
will come into repeated contact with water such as around a
sink or bathtub
13. Alkyd
Typically, modern commercially produced
varnishes employ some form of alkyd for
producing a protective film. Alkyds are chemically
modified vegetable oils which operate well in a
wide range of conditions and can be engineered to
speed up the cure rate and thus harden faster.
Spar Varnish
Spar varnish (also called marine varnish) is high quality,
waterproof, and sunlight-resistant varnish named for its use
on ship or boatspars and other woodwork where a glossy
finish is desired.
14. Drying Oils
By definition, drying oils, such as linseed and tung
oil, are not true varnishes though often in modern
terms they accomplish the same thing. Drying oils
cure through an exothermic reaction between the
polyunsaturated portion of the oil
and oxygen from the air.
15. Process of varnishing
1
Sand your wood. This will remove any imperfections and
blemishes before applying the varnish. Use 100 grit
sandpaper for unfinished pieces, and work with the
grain of the wood. Sand gently until the piece is
smooth.[1]If your piece is stained, use 240 or 280 grit
sandpaper.
16. 2 Clean your workspace.
Varnish is beautiful, durable finish, but it is prone to
attracting dust, hair, and other impurities before it dries.
Plan to varnish your piece in a place that is clean and will
not be disturbed.Try to apply the varnish in a different
location than the one you sanded your piece in.
If you have to use the same location, vacuum (don’t
sweep) thoroughly after sanding.
Wet mopping the floor before you begin can also help
keep dust down.
17. 3
Gather your varnishing supplies. You’ll only need a few
basic supplies to varnish wood. All of them are readily
available at your local hardware store. Make sure to
get:Varnish (read the label carefully to make sure it is
true oil-based varnish, not polyurethane)
4
Stir the varnish carefully. Avoid shaking the container of
varnish. Open it carefully, and use your stick to stir the
varnish thoroughly. Work slowly and gently -- you don’t
want to introduce air bubbles into the varnish.
18. Distemper
Distemper paint is an ancient type of paint made of water, chalk, and pigment.
It is bound with either an animal glue or the adhesive qualities of casein, a resin that
comes from solidified milk.
The primary problem with distemper paint is that it is not durable.
For this reason, it is used more often for temporary or inexpensive projects rather than
fine art
. Historically, distemper has been a popular interior paint for homes.
The Uses of Distemper
Distemper is an early form of whitewash. As a decorative paint, it is easily marked and cannot get wet.
It has been used since antiquity for painting walls and other types of house decoration. Because it's not
waterproof, it has most often been used on interior surfaces. In regions that seldom, if ever, see rain, it
can be used outside.
Distemper is much less expensive than oil-based paints. Due to this, it was also used for posters and
scenic backdrops on the stage. It has almost never been used for fine art paintings.
19. Distempering
The main object of applying distemper to the plastered surfaces is to create a smooth surface. The
distempers are available in the market under different trade names. They are cheaper than paints and
varnishes and they a present a neat appearance. They are available in a variety of colours.
Properties of distempers: Following are the properties of distempers:
(1) On drying, the film of distemper shrinks. Hence it leads to cracking and flaking, if the surface to
receive distemper is weak.
(2) The coatings of distemper are usually thick and they are more brittle than other types of water
paints.
(3) The film developed by distemper is porous in character and it allows water vapour to pass through
it. Hence it permits new walls to dry out without damaging the distemper film.
(4) They are generally light I colour and they provide a good reflective coating.
(5) They are less durable than oil paints.
(6) They are treated as water paints and they are easy to apply.
(7) They can be applied on brickwork, cement plastered surface, lime plastered surface, insulating
boards, etc.
(8) They exhibit poor workability.
(9) They prove to be unsatisfactory n damp locations such as kitchen, bathroom, etc.
20. 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 whiting or chalk is used as base instead
of whit lead and the water is used as carrier instead of
linseed oil.
