Painting Seminar Word

8/3/2019 Painting Seminar Word

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INDEX

1. INTRODUCTION.2. OBJECTS OF PAINTS.3. INGREDIENT OF PAINT.4. TOOLS REQUIRED FOR PAINTING WORK.5. TYPES OF PAINT.6. DRY DISTEMPER

7. DEFECTS IN PAINTING.8. COMPARISON9. References

FIGURE INDEX

fig no.1. Tools required for painting

fig no. 4.1 .

fig. No. 4.2


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1.INTRODUCTIONPainting is a finishing item in construction & hence this should be carried out with great

skill of workmanship. Painting affects the total appearance of the building from inside &

outside. Paint is indispensable for the proper maintenance and preservation of wooden structures

against working, checking or decay. Most of the metals corrode if not painted at suitable

intervals. Painting enables the masonry and concrete work to resist checking and disintegration

thereby extending the life of structure. Decoration, sanitation or improved illuminations are the

additional factors which often make painting necessary. Paint is composed of two main

components, Pigment and organic binder. Pigment is the solid ingredient of the paint and is used

in the form of a fine powder. Organic binder is the liquid part of the paint and it is called the

vehicle. The vehicle varies with the type of paint.

OBJECTS:-

Paints are used in building and other engineering works for covering the surfaces of

wood, metal, masonry, plastered walls, slabs etc.

Following are main objects of painting:

To protect the surfaces from atmospheric influences and other organic and to preservethem from the decay or oxidation and corrosion respectively.

To improve appearance of surfaces. To facilitate easy cleaning of the surface. To provide protection & decoration.

TYPES OF PAINTING WORK:

Painting is a final finishing item involving various types. Normally in building

construction painting work can be further divided as

a) Interior surfaces of flats / bungalows.b) Interior common areas of building.c) Exterior surfaces of building.

CHARACTERISTICS OF A GOOD PAINT:


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1. It should stick well to the surface and should be able to seal the porous sub strata.2. Its consistency should provide easy workability.3. The thickness of the paint film should be adequate for good protection and

decoration of the surface.

4. The paint film should dry rapidly.5. The dried paint film should be able to with stand the adverse weather effect for a

long time without losing gloss.

6. It should offer resistance to failure checking cracking and flaking.7. It should possess good moisture resistance.8. Its colour should not fade with the passage of time.

TOOLS REQUIRED FOR PAINTING:

Scrapping Patti, ladder, Zola, Distemper brush, Wash brush, Oil paint brush, Fine brush,

Scrapping papers 60 no., 80 no, 120 no., Measuring jar, Fine chisel and Hammer.

2. INGREDIENTS OF PAINT:


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1. Base2. Vehicle or Carrier3. Driers4. Coloring pigment5. Solvent.

BASE:

A base is a solid substance in fine state of division & it forms bulk of the paint. It

determines character of paint & impacts durability to the surface which is painted. It reduces

shrinkage cracks formed in drying & it also forms an opaque layer to obscure the surface of

material to be painted. E.g. White lead, red lead, Zinc white, Titanium white, Aluminum

powder.etc.

VEHICLE:

The vehicles are liquid substances which hold the ingredients of paint in liquid suspension.

They are required mainly for two reasons.

To make it possible to spread the paint evenly & uniformly on the surface in the formof thin layer.

To provide a binder for the ingredients of a paint so that they may stick or adhere tothe surface..

Eg: Linseed oil, Tung oil, Poppy oil, Nut oil.etc.

DRIER:

These substances accelerate the process of drying. Drier absorbs oxygen from the air &

transfers it to linseed oil, which in turn gets hardened. They are in form of soluble or paste

driers.

Eg: Litharge, red lead, sulphate of manganese is used as driers.


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COLOURING PIGMENT:

When it is desired to have different color than the color of the base of paint, coloring pigment

is to be used. The pigments are available in form of fine powders in various colors & qualities.

Four types of coloring pigments are:

1. Natural earth colors such as ochres, umbers, iron oxides etc2. Calcined colors such as lamp black, Indian red, carbon black, red lead etc..3. Precipitates such as Prussian blue, chrome green, chrome yellow etc.4. Metal powders such as aluminum powders, bronze powder, copper powder, zinc

powder etc.

SOLVENT:

The function of a solvent is to make the paint thin so that it can be easily applied on the

surface. It also helps the paint in penetrating through the porous surfaces. The most commonly

used solvent is the spirit of turpentine. The turpentine is inflammable evaporate rapidly and dries

the oil consequently. It is a transparent volatile liquid & it is obtained by distilling the resinous

exudation of some varieties of pine trees.

TYPES OF PAINTS:

1. ALUMINIUM PAINT

The very finely ground aluminum is suspended in either quick drying spirit varnish or slow

drying oil varnish as per requirement. The spirit or oil evaporates and a thin metallic film of

aluminum in formed on surface.

Advantages:

1. Visible in darkness.2. Gives good appearance to the surface.3. It is impervious to moisture.4. Surfaces of iron and steel are better protected from corrosion by this paint than any

other paint,

They are used for painting gas tanks, hot water pipes, marine pipes, oil storage tanks,

radiators etc.


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2. ANTICORROSIVE PAINT:

This paint essentially consists of oil and a strong drier. A pigment such as chromium

oxide, lead, red lead or zinc chrome in taken and after mixing if with some quantity of very

fine sand, it is added to the paint.

Advantages:

1. It in cheap.2. It lasts for a long duration.3. Appearance of paint in black.

3. CEMENT PAINT:

This paint consists of white cement Pigment, accelerator and other additives. It proves to

be useful for surfaces which are damp at the time of painting, for external finish on cement

plastered walls etc. It is mixed with water immediately before application. It is desirable to

provide cement paint on rough surface rather than on smooth surface because its adhesion

power is poor on smoothly finished surface.

Process:-

All exterior painting shall be carried out on scaffolding to achieve quality & use of a

zulla is to be avoided. The cement paint is applied in 2 coats.

Water the surface for at least 12 hours before applying first coat to assist thehardening process of the cement paint.

It should be seen that there is no presence of liquid water on the surface when thepaint is applied.

The application of paint over a surface exposed directly to the hot sunlight shouldbe avoided. Otherwise coating will dry before it is cured and will become chalky.

Apply the first coat by good quality brush immediately in vertical direction toavoid the brush marks occupying on the surface. Cure the first coat for 7 days, 6

times a day by using spray pumps. Fill up the hairs cracks with filler material.

See that first coat is little bit thicker. Apply second coat. Cure it for 7 days by spray pump or by water pipe. For tropical countries rewetting the surface before the application of second coat

is absolutely necessary.


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It is also essential to keep the surface wet after the final coat for about 2 days byfrequent splashing of water to get the best performance.

Application of cement paints during freezing should be avoided.

Advantages:-

1.It requires less skill and time.2.Preparation of surface is easy as it is not necessary to remove the previous coats of

cement paints.

3.Suitable for painting fresh plaster having high alkalinity.4.They become an integral part of substrata and add to its strength.5.They can be applied over new and damp walls.6.They prove economical as compared to oil paints.

4. EMULSION PAINT:

A variety of emulsion paint is available. It contains binding materials such as

polyvinyl acetate, synthetic resins etc. This paint is easy to apply and dries in 11/2

to 2 hours.

The surface is tough and can be washed with water. It possesses excellent alkali resistance.

The application can be carried out with either brush or spray gun. For long life, it is necessary

to have 2 coats.

5. ENAMEL PAINTS:

It contains lead or zinc oil, petroleum spirit etc.It dries slowly and forms a hard and

durable surface. The surface is not affected by acids, alkalis fumes of gas, hot and cold water,

steam etc. It can be used for internal and external wall surfaces. In order to improve the

appearance, apply coat of titanium white in pale linseed oil before coat of enamel paint.

6. OIL PAINT:

It is applied in 3 coats of varying composition such as:

Primer Undercoats Finishing coat.

It is cheap & easy to apply. It should not be applied during damp weather as it affects

the life of oil paint.


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7. PLASTIC PAINT:

This paint contains variety of plastic and application is done by brush or spray gun. It

is widely used for show rooms; auditoriums. It is used for internal jobs because they cannot

resist atmospheric action. The success of paint will depend on quality of plaster and

characteristic of base surface. The application of these paints should be done with clean

brushes or sponge rollers. These paints are water based and hence not suitable for metallic

surfaces. These paints allow moisture to evaporate through minute pores. But even then it is

desirable to allow 4 months, preferable one year for moisture to escape from fresh masonry

& plaster. The thickness of coat should neither be too thin or thick. It must possess elasticity

to match stress in plaster. It is desirable to wash surfaces with wet cloth lightly at least once

in month. If this precaution is not taken dust particles would adhere to surface and paint may

loose its good appearance.

8. PAINTING PLASTERED SURFACE:

The greatest danger in painting plastered surfaces, particularly if they are relatively fresh,

is the free alkalis present in the lime or cement. The free alkalis discolor the paint, destroy its

oil and adversely effect the drying properties of the paint applied. Therefore preparation of the

surface before painting is extremely important. The plastered surface should not ordinarily be

painted until it has dried completely. If possible leave the walls unpainted for at least first 12

months so that they may dry out completely.

The walls may however be white washed or color washed for this duration. In new

work, however the surface should be washed with a dilute solution of zinc sulphate to neutralize

the free time on the walls. Before primer is applied the holes and undulation should be filled up

with the Plaster of Paris and surface rubbed smooth. Primer for plaster work may be prepared by

mixing equal parts of white & red lead in boiled linseed oil.

After the primed surface has dried, two or more coats of the desired paint may be

applied in the usual way.


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DRY DISTEMPER

Dry distemper is normally applied on smooth finished surface of wall in flats/bungalows.

There are various shades available in the market. Selection of shades should be approved bychief engineer. Shades can be made as required.

SURFACE PREPARATION FOR DRY DISTEMPER

Clean the wall surface thoroughly. Remove donga completely by scraper & polish paper. Rub the wall surface by fine grade paper 120 no. as required ensuring proper

adhesion of color Clean all greasy spots and smoky surfaces with special attention.

WORK PROCEDURE FOR DRY DISTEMPER

Dry distemper can be applied by two methods.

1. Dry distemper with primer and putty over wall.2. Simple three coats of dry distemper.

The first method is costliercost of first method is about double the second method i.e.

without primer & putty. Primer and putty gives smooth finish and it overcomes all defects

such as cracks, undulations in the wall. For bungalows or A class schemes dry distemper

with primer putty is preferred.

DRY DISTEMPER WITH PRIMER AND PUTTY:

Primer preparation and application

1. Prepare a primer by adding 0.40 lit of turpentine to 0.80 lit. of ready made cement primerto cover 10 sqm. (108 sft) of wall surface.

2. After surface preparation apply primer by brush on total surface of wall.3. Allow primer to dry for at least 24 hours.


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Putty preparation and application.

1. Engineer should check and ensure that contractor is following the correct procedure ofpainting.

2. Prepare putty by mixing 3kg.whiting powder with 0.25 lit., cement primer, 0.25litsynthetic enamel, 0.15 lit. linseed oil & 1 lit. water to cover 10 sqm wall surfaces.

3. Fill up all undulations of minor nature, dents, cracks in proper way so that the surfacebecomes completely smooth to receive paint (Refer fig.)

4. Where the dents are deeper the filling must be done with filler paste of thickerconsistency and Plaster of Paris.

5. After 24 hours surface should be rubbed with fine paper to get a smooth finish and evensurface over the wall.

6. Clean the wall surface by dry cloth to remove all dust and particles in powder form.Prepare the wall to give first coat of distemper.


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First coat of distemper

1. Use 1kg of any distemper to coat 10 sqm area.2. Add water 0.8 lit. for one kg of distemper.3. Add 25 gm glue in one kg of distemper to get more adhesion of paint to wall surfaces.4. Stir this mixture constantly with a bamboo stick while it is being used.5. Use 10 cm (4) bristle hairbrush for application of distemper.6. Apply the brush first horizontally immediately in vertical direction taking care that there

are no brush marks lefts on the surface after coat has dried.

7. Dried surface of wall should not appear powdery & it should not easily stain the handwhen rubbed.

8. Clean the flower immediately.9. Allow first coat to dry for at least 24 hours & then start 2nd coat.

Second and third coat of distemper

1. Use 0.5 kg of dry distemper to cover 10 sqm. (108sft) Area.2. Add adhesive/give, 25 gm for one kg of paint.3. Stir thin mixture constantly with bamboo stick4. Apply dry distemper in the same manner as explained for first coat.5. Apply successive coats of painting only after prior coat has dried completely and in any

one not either than 12 hours.


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FOR DRY DISTEMPER WITHOUT PRIMER AND PUTTY.1. Prepare the surface as explained in surface preparation.2. Apply first coat of dry distemper directly on prepared surface as per procedure

given earlier.

3. Do not use primer and putty before first coat.4. After first coat fill all undulation of minor nature dents coats in proper way by

applying putty so that the surface becomes completely smooth.

5. Where the dents are deeper the filling must be done with filler paste of thickerconsistency & Plaster of Paris.

6. After drying putty (for 24 hours) surface should be rubbed by fine polish paper toget smooth finishing.

7. Apply second coat similarly & as explained above.8. After second coat, see if any cracks, dents are present. If observed they should be

filled & proper rubbing should be done by fine polish paper.

9. Apply 3rd coat as final coat of paints.10.After drying check & make sure that there are no brush marks, or color

variations.

11.Clean the floor area.12.See that junction of ceiling white wash & wall distemper is painted in proper line

& level.


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DEFECTS IN PAINTING

Following are the usual defects which are found in the painting work:-

I) BLISTERING:

This defect is caused by the water vapour which is trapped behind the painted surface. Theformation of bubbles under the film or paint occurs in this defect. It may occur from various

causes such as imperfect seasoning of timber; excess oil used in final coat etc.

II) BLOOM:

In this defect the formation of dull patches occur on the finished polished surface. It

is due to the defect in paint or bad ventilation.

III) FADING:

The gradual loss of color is known as the fading & it is mainly due to the effect of

sunlight on pigments of paints.

IV) FLAKING:

A small portion of the painted surface is sometimes seen loose. It is known as the

Flaking & is due to poor adhesion.

V) FLASHING:

Sometimes, the glossy patches are seen on the painted surface. This is known as the

Flashing & it is mainly due to poor workmanship, cheap paint or weather actions.VI) GRINNING:

When the final coat of paint has not sufficient opacity, the back ground is clearly

seen. This is known as the grinning.

VII) RUNNING:

The paint runs back & leaves small areas of surface uncovered. This defect

occurs when the surface to be painted is too smooth.

VIII) SAGGING:

When aviation or inclined surface is painted too thickly, the defect of sagging occurs.

IX) SAPONIFICATION:

The formation of soap patches on the painted surface is termed as the Saponification

and it is due to chemical action of alkalis.

X) WRINKLING:

When a horizontal surface is too thickly painted, the defect of wrinkling becomes prominent.


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COMPARISION

Cement paint Distemper

i)

ii)

iii)

iv)

v)

vi)

vii)

viii)

ix)

x)

It consists of white cement, pigment,accelerator & other additives.

Comparatively costlier.

Coating is thinner.

Film developed is not porous.

Workability is better.

They are mixed with water at normal

temperature.

Available in dry powder form.

Adhesion power on smooth surface is low.

Requires less skill, time for application.

Suitable for application over fresh plaster.

.

i)

ii)

iii)

iv)

v)

vi)

vii)

viii)

ix)

x)

It consists of whiting chalk as base &water as carrier.

Comparatively cheaper.

Coating is thicker.

Film developed is porous.

They exhibit poor workability.

They are mixed with hot water before

use.

These are available in powder as well

as paste form.

Comparatively adhesion power on

smooth surface is good.

It requires skill for application.

Not suitable for application over fresh

plaster.

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Painting Seminar Word