Paints are used to protect surfaces from weathering and corrosion and improve appearance. They are composed of a base, vehicle, pigment, thinner, and dryers. The base forms the main paint film and provides hardness and abrasion resistance. The vehicle is an oily liquid that dissolves the base and pigment and allows the paint to spread easily. Pigments provide color. Thinners increase fluidity and penetration while dryers accelerate drying. Good paints apply smoothly, dry quickly to a durable film without cracks or brush marks, and maintain their color without fading over time. Old paint can be removed by burning, chemical strippers, or alkaline solutions left on the surface.

1. Paints are used to protect metals, timber, or plastered
surfaces from the corrosive effects of weather, heat,
moisture or gases etc and to improve their appearance.
COMPOSITION OF PAINTS
Fundamental components of an oil-based paint are

2. A) BODY/bases
• Forming the main body of a paint
• Make the paint film harder and
more resistant to abrasion
• Reduce shrinkage cracks on drying
In white paint ; body is also the pigment
Commonly used bases are White lead,
Zinc oxide, Iron oxide, Metallic
powder such as Al, Cu, Br
Paints more often named after the base
as Lead paint, Zinc paint, and
Aluminum paint

3. B) VEHICLE
• Oily liquid in which the body and
pigment are soluble
• Facilitates the paint to be conveniently
spread over the surface
• Oil most commonly used as vehicle are
Linseed oil, Soya bean oil, Fish oil,
dehydrated castor oil
C) PIGMENT
Pigments are materials which gives the paint
its color
In white paint the body is the pigment
Natural pigments (natural iron oxides,
chrome oxides)
Synthetic pigments (phthalocynines ► coal
tar derivatives)

4. D) THINNER
Liquid thinner is added in the paint to
• Increase fluidity
• Making paint more smooth
• Help penetration of porous surfaces
Common thinner ► turpentine (made by
distilling gum from a number of pine
trees)
E) DRYERS
• Added to quicken the drying of vehicle
• Organic salts of Iron, zinc, lead,
manganese, Ca
to accelerate the oxidation and hardening of
vehicle

5. PREPARATION OF PAINT
• Base/ body is thoroughly grounded in
the vehicle
• Mixed with the thinner to impart
necessary workability
• Pigments and dryers are separately
mixed to a thin consistency
• The above two are then thoroughly
mixed to form the desired paint
CHARACTERISTICS OF A GOOD PAINT
• Work smoothly/ capable of being laid in
a thin coat with the brush
• On drying it should be durable and
tough
• Color of paint should not change or fade
(darken or weaken) with the passage of
time
• Surface ► dry in 9 hours
• No cracks on drying
• No brush marks on drying ► pleasing
appearance
• Should not damage the painted surface

6. REMOVAL OF OLD PAINTS
A) Burning the paint
• Economical/ quick
B) Applying paint remover
1) Hot solution of equal parts of soap/
potash/ quick lime applied
• Keep it for 24 hours
• Wash with hot water to remove the paint
2) Two parts of quick lime/ one part of
washing soda mixed with water
Cream spread on painted surface ► leave for
one hour
Wash / remove the paint
3) Solution of Caustic soda in water applied
to the surface