Paint ,varnishes and distempers

PRESENTATION ON PAINTS,VARNISHES AND DISTEMPERS

PRESENTED TO MD. MOTIUR RAHMAN ASSISTANT PROFESSOR DEPT. OF CIVIL ENGINEERING

PRESENTED BY 1. DIPU KUMAR PK(141128) 2. S.M. MAHFUZUL HAQUE(141129) 3. MD. AL MAHMUD(141130) 4. SUMON CHANDRA ROY(141131) 5. KRISHNO SAHA(141132)

PAINT

A Paint is a Solution or suspension (emulsion) of pigment, binder, and mineral solvent (or water) that on drying forms an adhering film on the surface it is applied for protection and/or decoration.

CONSTITUENTS OF AN OIL

An oil paint is generally made up of six main constituents given below: a. A base b. An inert filler or extenderc. Colouring pigmentd. A vehiclee. A solvent or thinnerf. A drier

CHARACTERISTICS OF A GOOD PAINT

A good paint should have the following characteristics:1. It should stick well to the surface and should be able to seal the porous substrata.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 withstand the adverse weather effect for a long time without losig gloss. 6. It should offer resistance to failure by checking ,cracking and flaking.7. It should posses good moisture resistance.8. Its colour should not fade with the passage of time.

BASESThe pigments commonly used as the principal constituents for forming the body of various types of paints are given below: 1. White lead 2. Red lead 3. Lead 4. Zinc white or zinc oxide5. Iron oxide6. Titanium white or titanium dioxide7. Iithopone

VEHICLE The vehicles commonly used in an oil paint are briefly described below:1. Linseed oil2. Raw linseed oil3. Boiled linseed oil 4. Double boiled linseed oil5. Poppy oil6. Tury oil 7. Nut oil

COLOURING PIGMENTS

Colouring pigments are used to give the desired colour to the paint. The colouring pigments generally used are given below:a. Black pigments : lamp black, vegetable black,

graphite.b. Brown pigments :Raw umber, burnt umber.c. Blue pigments: Prussian blue, ultramarine

blue.d. Yellow pigments: chrome yellow, yellow ochre.e. Red pigments: Indian red, red lead.f. Green pigments: Green earth, chrome green.

TYPES OF PAINTS1. Aluminium paints2. Anti-corrosive paints3. Asbestos paints4. Bituminous paints5. Bronze paints6. Cellulose paints7. Casein paints8. Cement based paints9. Enamel paints10. Oil paints11. Rubber base paints

ALUMINIUM PAINTS

ANTI-CORROSIVE PAINTS

ASBESTOS PAINTS

CEMENT BASED PAINT

OIL PAINTS

PROCESS OF PAINTING DIFFERENT SURFACES:

The process of painting on new wood work can be divided into the following stages: 01. Preparation of surface 02. Knotting 03. Priming 04. Stopping 05. Surface coats or under coatings 06. Finishing coat

PAINTING WITH BRUSHES Prior to painting ,the loose bristles should be removed by taping the brush gently against the palm of hand ,twirling it rapidly between the palms of hand and finally putting the loose bristles out .The brush should not be dipped too deeply in the paint, and the excess paint should be removed by gently rubbing the brush against the inside surface of the paint pot.

SPRAY PAINTINGPainting with the spray gun is considered to be a highly developed and efficient method of applying all types of protective coatings. There is also economy in labour and the consumption of material as only two coats of spray are considered sufficient to obtain the desired finish .The process of painting with spray machine may be summarized as below.

VARNISHVarnish is a clear, pale solution of a resinous substance (like amber, common resin, copal, lac or shellac) dissolved in either oil, turpentine or alcohol. Varnish plays an important role in finishing wooden surfaces of doors, window, floors etc.

TYPES OF VARNISH

1. Oil varnish2. Spar varnish3. Flat varnish4. Asphalt varnish5. Spirit varnish

OIL VARNISH

SPAR VARNISH

FLAT VARNISH

ASPHALT VARNISH

SPIRIT VARNISH

FURNITURE POLISH

The following mixture will be made an excellent furniture polish:

MATERIAL QTY REQUIRED

01.Linseed oil 16 litre

02.Methylated spirit 2 litre

03.Vinegar 1litre

04.Turpentine 1litre

05.Copal varnish 1litre

06.Muriatic (hydrochloric acid) 0.75litre

DISTEMPERSDistempers may be defined as water paints consisting of whiting (powdered chalk), some colouring pigment (if desired) and glue size mixed in water.

Distemper may give either a washable or non-washable surface according to the medium used.

They are cheaper than paints and varnishes and are easier to work.

DISTEMPERING WITH DRY DISTEMPER

The new plaster is allowed to dry for at least two months before applying distemper. However, incase of old surfaces ,all dust ,dirt, scales and greasy marks should be removed and all the holes and cracks should be filled with plaster of Paris mixed with dry distemper of the colour to be used. A coat of whiting is then applied over the prepared dry-clean surface which acts as the priming coat for the distemper. The dry distemper is then converted into a liquid by mixing it with water and stirring it well .As a rule 0.6 litre of water should be used per kg. of distemper.

OIL BOUND DISTEMPER

A distemper or water based paint that contains some drying oils to enhance its spreading and drying characteristics .It is form of distemper in which the drying oil is rendered mixable with water. The distemper in pasty form is available in different shades in sealed tins.

CASEIN PAINTSCasein is a protein substance derived from milk curds. Casein paint is made by working a mixture of finely ground casein (which acts as a binder) with a base of white pigment which is usually slaked lime, and is sold in powdered or paste form in sealed tins. Casein paints , on account of their high opacity , give pleasing results in one coat. They are applied on new plaster without any danger of blistering, scaling or any adverse effect of free alkali.

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