PAINTS(defects) AND DISTEMPERS

PAINTS

• Cheap, durable, can be easily applied

• Used as interior works of buildings

• Decorative in appearance than whitewash and colourwash

• Colouring pigments are added that are available in different shades

Distempers=water paints consisting of:

>powdered chalk as base with glue

>resin or acrylic as binder>water as carrier or thinner

• They are available in two forms:

>ordinary distemper as dry distemper

>oil bound distemper

Paint Defects

(1) Cratering

(2) Dust (nibs)

(3) Orange peel

(4) Sagging

(5) Poor opacity

Cratering / Fish-eyes

Cratering and Fish-eyes occurs partly on the paint surface, and the film becomes uneven.

Cratering (phenomenon from base material)

Fish-eyes (phenomenon in paint film layer)

Cratering / Fish-eyes (cause-result analysis chart)

Cratering

Application work

Paint / Putty

Drying

Others

Poor drying of puttyThick application of lacquer type putty

Insertion of polyester putty between lacquer

paint films

Too thick application of excessively diluted

paints

Strong dissolvability of topcoat paint.

Absorptive putties

Excessive adding of non-blushing

thinner

Poor sanding of putty

Cratering / Fish-eyes

Measures

Precautions

Remedy

Most of the troubles can be

resolved by avoiding the factors

Slight fish-eyes shall be repaired with dry mist spraying.

Large sized (cratering) shall be abraded off

completely after drying, and repaint.

Circumstances

Facility & Equipment

Application work

Materials

Dust (Nibs)

Popping appears on the film surface.

Popping

Dust (cause-result analysis chart)

Dust

Facility & EquipmentMaterials

Circumstances Application works

Insufficient cleaning of

the painting work floor

Dusty working clothes

Insufficient filtration of paint

Shortage of booth air pressure

Defects of booth filters

Insufficient cleaning of spray guns

Defects of air cleaner

Insufficient cleaning of car body

Trash of masking papers (newspapers, etc)

Insufficient cleaning of spray gun

Dust (Nibs)

Measures

Precautions

Remedy

Keep painting area clean, and free from trashes and dusts.

Wear anti-dust working clothes, and use proper masking

paper and tapes.

Abrade off small nibs with a knife or grinding stone, and

polish it up with compounds

Prevent working area from floating dusts by watering the

floor before painting.

Orange peel

Paint surface become uneven like orange peel.

Orange peel (cause-result analysis chart)

Orange peel

CircumstancesApplication works

Materials Facility & Equipment

Low liquidity of paint

High temperature

Too fast blowing speed

High temperature of car body

Thin paint film

Low spray pressure

Insufficient spraying emission volume

Too fast gun speed

Too long spray gun distance

Too high viscosity of thinner

Too quick evaporation of thinnerToo big size of spray gun nozzle

(insufficient atomization of the paint)

Defects of spray pattern

(insufficient cleaning of spray gun)

Orange peel

Measures

Precautions

Remedy

Slow evaporation speed of solvent

Maintain liquidity of paint

Apply water sanding (#800～#1000), and polish up

gradually with compounds (Medium→Fine→Extra fine).

Decrease viscosity of paint.

Sagging

SubstratePaint film

Paint film partly becomes too thick and the paint sags.

Sagging (cause-result analysis chart)

Sagging

Application workCircumstances

Materials

Facility & Equipment

Too slow evaporation of thinner

Thick paint film

Too big size of spray gun nozzle

(insufficient atomization pf paint)

Low temperature of car body

Low temperature

Defective spray pattern

Low spray pressure

Too much spraying emission volume

Too short spray gun distance

Defective spray pattern

Too low viscosity of paint

Sagging

Measures

Precautions

Remedies

Make set-to-touch time faster

Use proper thinner to avoid excessive coating.

Overall sagging : abrade off whole area, and refinish.

Adjust spray pattern, gun distance, and gun speed to proper

level.

Slight sagging : abrade off the sagging area, then apply

compound (fine→extra fine )

Poor opacity (Poor hiding power, or Lack of hiding)

The color of undercoat is not hidden caused by poor pigmentation, or insufficient film thickness

Poor pigmentation

Insufficient film thickness

Poor opacity (cause-result analysis chart)

Poor opacity

Application works

Materials

Too thin film coating

Insufficient agitation

Specific nature of tinter

Too much diluted

Lack of hiding power

Poor opacity

Measures

Precautions

Remedy

Spray paint in proper film thickness after sufficient agitation

Repaint until the undercoat is completely hidden.

Avoid excessive dilution.

Apply back-up undercoat of similar color shade in

case of poor hiding colors.

ENAMEL PAINT

• A type of paint that has a hard, glossy and opaque finish.

• The term “enamel paint” is generally used to refer hard surfaced paint with a high gloss finish.

INGREDIENTS OF ENAMEL PAINT

• Enamel paints are made by adding varnish in ordinary oil-based paint.

• The solvents are usually aromatic hydrocarbons toluene and methyl ethyl ketone, the binders are vegetable oils, alkyds and acrylics and vinyl acrylics.

• The pigments constitute clay, calcium carbonate, mica, silica's and talc's, while the additives are diatomaceous earth, talc, lime and barite.

Applications of ENAMEL PAINT

1. WOOD WORK• The surface should be clean AND

DUST FREE• The wood work to be painted

should be dry • All unevenness should be SMOOTH• before painting wood work Priming

coat should be applied

2. PLASTERED SURFACE• The painting work IS DONE

AFTER THE WALL IS DRY • The surface should be clean AND

DUST-FREE• SURFACES SHOULD BE VOID-

FREE (NO HOLES ON SURFACES)• good quality of primer SHOULD

BE USE FOR THE SURFACES

3. IRON AND STEEL SURFACE

• All rust SHOULD BE REMOVED

• The surface should be clean AND DUST FREE

• Good quality of primerSHOULD BE APPLIED ON TO THE SURFACES

A) ADVANTAGES OF ENAMEL PAINT

1.Comes in container and ready to use. 2.Tough durable and stain resistant 3. Washing capability is better compared to plastic paint. 4.Last for a long period of time as it provides a durable finish. 5.Can be applied on both interior and exterior surfaces. 6.Provides a glossy and smooth finish surface.

a) Disadvantages of enamel paint

1. Takes a long time to dry

FIRE RETARDANT PAINTS

>formulated with silicon and polyvinyl chloride to reduce flame spread of combustible material

BITUMINOUS PAINTS:

• prepared by dissolving asphalt and mineral pitches and used for iron work in water

LUMINOUS PAINTS:

• contains calcium sulphide with varnish

• Surface on which luminous paint is applied shines like radium dials of watches after the source of light being cut off

• Should be applied on surfaces that is free from corrosion and lead paints