letters and memos

PRESENTATION NO 1

PRESENTED TO :SIR TAHIR SULTAN

PRESENTED BY : EVEN GROUPSESSION : 2008-13DATE : 26-01-2009SUBJECT : BUILDING MATERIALS

DEPARTMENT Of ARCHITECTURAL

ENGINEERING

TOPICS OF PRESENTATION

PAINTING PAINTING NEW WOOD WORK RE-PAINTING WOOD WORK PAINTING OF PLASTER SURFACE ENAMEL PAINTS DISTEMPER TYPES OF PAINTS

PAINTING.

Painting is defined as the application of paint to a surface either with a brush or by spraying.

INSTRUCTIONS FOR PAINTING

Characteristics of the surface for painting. Weather conditions. Quality of material used in paints. Quality of brush.

PAINTING NEW WOOD WORK:

Following points should be attended to before painting new wood work.

Well seasoned timber. Not to paint excessively dry wood. Dry surface. Quality of the surface to be paint. In cause of nails. In cause of knots.

Knotting

The repairing of knots in timber to make it smooth and easy for painting and other engineering works is called knotting.

KNOTKNOTKnot is a particular type of imperfection in a Knot is a particular type of imperfection in a piece of timber, a knot will appear as a roughly piece of timber, a knot will appear as a roughly circular "solid" piece of wood.circular "solid" piece of wood.

TYPES OF KNOTTING

Three types of knotting is generally done. These are:

1. Ordinary or size knotting2. Lime knotting3. Patent Knotting

ORDINARY KNOTTING

i. First a hot coat of ‘red lead +glue+ water’ paste is applied.

ii. Time to dry it.iii. 2nd coat of red lead + linseed oil & thinned

with turpentine oil is applied.

LIME KNOTTING

i. First the knot is filled with hot lime and left cover with it for 24 hours

ii. After drying it will scrapped.iii. Then knot is coated with ordinary knottingiv. In the last the knot is rubbed smooth with

sand paper.

PATENT KNOTTING

2 coats of varnish

1litre methylated spirit +250gm of shellac +15gm of red lead

APPLICATION OF PRIMING COAT.

After knotting priming coat is applied It provides a smooth base for paint 1kg red lead +white lead mixed in 1 litre of oil

STOPPING

oAfter the priming coat is dried, all cracks and holes are filled up with putty .

oWhen putty becomes hard the surface is rubbed with sand paper.

APPLICATION OF FINISHING COAT

After knotting, priming and stopping the surface is ready for 1 or more coats of paints

Each coat is applied after the first one is dried and has been slightly rubbed with fine glass paper

A little copal varnish is added into final coat to withstand weathering

REPAINTING WOOD WORK

“It is a process in which the old painted surface is painted again”

NECESSITY

DEFECTS AND ITS REMOVAL:Defects

•Unsound,unsightly,blisterig or flaking off

•Disfigured by smoke

•Holes and cracks etc.

Removal of defects•It will remove by application of some paint remover or by burning the paint•1kg glue + 60gm of unslaked lime in 4kg of water is applied on the surface•It will fill up with putty

NOTE:

Before the application of each coat the surface will be rubbed smooth with sand paper.

Two or three coats of paints is applied till the desired shade is attained