S1-S2 BT

1. PAINTING

2. PAINTING
•Protect the surface of wood,
metal and all structures from
atmospheric influences.
•Prevent decay in wood
•Prevent corrosion in metal
•Provides clean ,smooth and
colored surface

3. Ingredients of paint
Base- solid matter
• Bases-White lead, red lead, oxides of zinc,
antimony white
Liquid vehicle
• carries the solid matter
• Acts as binding material
• Vehicles- linseed oil, Tung oil, stand oil, nut oil

4. Additives
 Pigments- coloring agent
Thinning agents- reducing consistency of
paint- turpentine oil
Driers- property of quick drying- cobalt, lead,
manganese
Function- to absorb oxygen from the
atmosphere and transfer it to
linseed oil for hardening.
Inert filler/Adulterant-
improving the durability
- Barium sulphate

5. Characteristics of good paint
• Good spreading power
• Dry quickly
• Durable, tough, resistant to wear on drying
• Color should not fade or change
• Should work smoothly and freely
• Become dry within 9 hours
• Not crack on drying
• Smooth and pleasing appearance.

6. Type of paints
• Enamel paint
• Emulsion paint
• Distempering
(water paint)

7. Enamel paint
• It Consists of white lead or zinc white,oil,petroleum,
spirit and resinous matter.
• Dries slowly and forms a hard durable surface
• Not affected by gases,acids,alkalies,hot water and cold
water, steam and temperature.
• Used for external and internal walls.
• Before applying paint, One coat titanium white in pale
linseed oil is applied

8. Emulsion paint
• It contains binding material like polyvinyl acetate and
synthetic resins
• For long life-two coats of emulsion is applied
• Apply a coat of cement paint before applying emulsion
Advantages
• Easy to apply and dry within two hours
• Long lasting paint with no change in color
• Possible to clean the surface with water
• Possess good weather resistance and alkali resistance

9. Distempering
• Water paint
• Prepared by mixing powdered chalk(white) and glue, boiled in
water
• Earthly pigments- umber, Indian red and lamb black –give color
shade
• Powder or paste form- mixed with hot water to form viscous fluid
• Distemper is porous
• Allow water vapor to escape
• less durable.
• Use- to give smooth outer surface in low cost

10. Preparation of
different surfaces for painting
• Painting on new wood work
• Painting on old wood work
• Painting new iron and steel work
• Painting old iron and steel work
• Painting plastered surfaces

11. Painting on new wood work
• Moisture content of timber must be less
than 15% of their dryweight
• Four coats of paints are required
• Before Prime coat
 Wood work to be cleaned thoroughly
 Nail holes and cracks to be filled with
putty
 Rub the surface with water proof
abrasive paper.

12. • Prime coat
• Pores get filled and opaque covering formed
over the whole surface.
• First coat
• Surface is rubbed with pumic stone- stopping
Each coat applied only after previous coat has
dried completely

13. Repainting on old wood work
• Old paint should be completely removed
• Removing old paint
– Equal parts of washing soda and quick lime- mixture is
brought to a paste form by adding water
– It is applied on the surface and kept for one hour, then
washed off with water
• After, wood surface is painted as that for new wood
work.

14. Painting new iron and steel work
• Clean the surface by
scrapping/brushing with steel wire
brushes
• Phosphoric acid is used to remove the
scale deposit on surface.
• Prime coat is applied using brush
• Two or more coats with a brush /spray
gun
• Each coat applied only after previous

15. Repainting old iron and steel work
• Before repainting, it should be thoroughly washed with
soap water
• If grease is present it may be removed by lime water.
• Remove old paint by flat oxy-acetylene flame over the
metal and then scrapped the surface with wire brush.
• Washed with solution of caustic soda and slaked lime.

16. Painting plastered surface
• For newly plastered wall, there is considerable amount of
moisture.
• For applying paint wait for at least 3to 6 months.
• Defects in plastered surfaces are to be removed.
• Coats of alkali resistant primer paint should then be applied
on the surface.
• Usual paints:- cement paint, silicate paint, emulsion paint

17. Thank yo u