The Time Value of Money

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Paints and Varnishes
By Engr. Dr. Attaullah Shah
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Paints

• Uses
• Preserve material
• Gives required color to surface applied.
• Aesthetics
• Oil Paints are most commonly used.
• 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

• 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.

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Proportioning of Ingredients of Paints

• 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?

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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

• 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.

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Varnishes

• 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.

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Resins

• 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