Transcript The Time Value of Money

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Paints and Varnishes
By
Engr. Dr. Attaullah Shah
Paints
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Uses:
 Preserve
material
 Gives required color to surface applied.
 Aesthetics
 Oil Paints are most commonly used.
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Oil Paints:
 Following
constituents:
Base: Iron oxides, white lead, zinc oxide, red lead.
 Vehicle: Linseed oils (Pale yellow).
 Driers: Added to dry quickly and harder. Red lead.
 Thinner: To reduce viscosity of paints.
 Pigments, color or strains. Spirit of Turpentine
 Coloring pigments: To give the desired color
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Preparation of Paint:
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The base ingredients are thoroughly ground in oil and
thinned by the addition of oil and turpentine.
The pigments are separately mixed with oil and
Turpentine added to make it fluid.
The two mixtures of base and pigments are added and
turpentine added to make it workable.
The grinding of base is done with the grinding roller mill
Before application of the paint, the surface is scrapped
cleaned.
Ready Mixed Paints:
 Which have been mixed by the
Manufacturers.
 Burgers, Robbialic, ICI Dulux etc.
Proportioning of Ingredients of Paints
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It depends on the following factors:
 Nature of Material to be painted. Wood, Iron
 Types of Surface
 Nature and Appearance of the work
 Climatic conditions
 Skill of the painter
 Quality of ingredients.
 Nature of Coats applied.
 Anything else in your mind?
Aluminum Paints
Finely ground Aluminum suspended in a
medium of slowly drying
 Costly and used for decorative purposes.
 Protects Irons and steels from corrosion.
 Used for painting marine works.
 Resists heat and good for radiators and
hot water pipes.
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Water Paints
The medium is water.
 Certain amount of glue added to form
emulsion.
 Used only for inferior works.
 For decoration of exterior works and
stucco surfaces.
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Distempers
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Water paints having oil and water as thinning agent.
Glue starch or Casein resin used as base together with
a pigment to suit the required color.
For base whiting chalk is used as base.
Distempers are used for application of interior works
except wood and iron.
Oil bound distempers are used in the form of solid
pastes and thinned with water before use.
Distempers are washable.
Varnishes
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Gives brilliance to the surface.
Generally transparent
Resins are dissolved in rapidly solvent such as
Turpentine, oil etc.
Varnishes dry quickly and give hard surface to
protect them from harsh weather.
Generally applied to wood, furniture and
building works.
Sometimes used over paint work for shining.
Resins
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Obtained from natural gums of various trees.
The following resins are used for preparation of
varnishes.
 Shellac: Obtained from the trees of pipal,
generally known as “Lakh”
 Amber: Yellow hard transparent durable
substance found between the beds of woods
and coals.
 Copal or Gum Anime
 Kauri
 Dammar