|THE KEY TO GET BEST RESULT OF PAINTS
The best performance of Paints mainly depends on following factors:-
(A) Nature of Surface: - Surface preparation.
(B) Method of application of Paints: - Selection of correct method.
(C) Quality of Paints: - Selection of the right quality paint for the job in hand.
| Nature of Surface: - Surface preparation
Adhesion of the paint film to the substrate depends on the degree of cleanliness of the surface. Proper surface preparation contributes more to the success of the paint protective system than any other single factor.
Rust is a mixture of hydrated ferrous & ferric oxide. Moisture & oxygen (from air) are promoters of rust. Rust is a porous, Spongy material occupying much greater volume than the iron from which it is derived. It has bad influence not only on the adhesion of the paint to the surface, but also on the paint system itself, resulting in blistering, peeling film rupture by growths of rust volume etc.
GreaseGrease or oil, even a thin layer, affects not only adhesion but it may be also absorbed in the coating & thereby prevent development of maximum hardness, resistance to abrasion or attack by chemicals. Contamination trapped between paint coats can adhesion failure & accelerate water or chemical or atmospheric agent penetration.
The good surface preparation means to remove all contamination, corrosion or any other defect of the surface. Many methods are available for surface preparation & the choice amongst them is by & large influenced by the mature of the substrate, the condition of the surface & the corrosiveness of the environment. Depending on the extent of corrosion that has already occurred sometime it would be necessary to choose more than one method or a combination of method of surface preparation. The various methods available are: -
- Chemical Treatment.
- lame Cleaning.
- anual Cleaning.
- Mechanical Cleaning.
- Blast Cleaning.
1. Chemical Treatment:-
This is done by immersion of the object in acids; the most commonly used being hydrochloric acid. The whole process involves a multi tank operation & includes a degreasing as well as a phosphating operation. At different stage of the operation through & proper rinsing with water has to be carried out to remove residuals of untreated acids. This method is most suitable in production line where surface areas are not large & can be easily handled.
2. Flame Cleaning:-
In flame cleaning old paint, loose scale etc. from the surface of a metal is removed by direction an oxyacetylene flame to the surface where such cleaning is required. It is an expensive & time consuming process & not much used in practice.
3. Manual Cleaning:-
Manual cleaning consists of chipping & scraping followed by vigorous wire brushing & emery paper cleaning. It is most suitable for remove loose rust, scale & old coatings. In this process residual rust & scale is always left behind. This method is employed for spot cleaning during maintenance painting.
4. Mechanical Cleaning:-
Under this process traces of oil & grease are first removed by solvent wiping such as with mineral turpentine, petrol, petroleum solvent, trichloroethylene, tri sodium phosphate or by detergent degreasing. Secondly layers of scales & rust removed by hand tools & then remaining rust & scale removed by the use of sanding machines, scales, needle guns or rotary discolors.
5. Blast Cleaning:-
Blast cleaning is process by which the surface is prepared by bombardment with small hard particles, directed at the surface at high velocity resulting in the dislodging of all scale & rust. To some extent, even the steel surface itself is ruptured.
Generally abrasives used are chilled iron grit or shot, sand or silica, slag from steel plants etc. Selection of abrasives depends on the required extent of cleaning & the surface profile required after cleaning.
| Method of application of Paint: - Selection of correct method
Before proceeding with application of paint, the following instructions should be followed: -
i) Remove dirt, dust etc. from the drums & tins.
ii) If there is skin on the paint, remove it.
iii) Stir the paint carefully (stirring, not shaking) & thoroughly. Mostly complaints on paints are
not due to quality of paints but due to poor & inadequate stirring. Always use a flat
(not round) object for stirring with upward movements to mix the pigment & vehicle
iv) Filter the paint through a wire-mesh muslin cloth or nylon bolting cloth.
v) In case of two - component paints always check the pot life mentioned in the Technical Data
sheet. Mix only required quantity to apply within the specified time. Any left over is a waste
& cannot be reused.
vi) During mixing, follow mixing instructions carefully. Keep stirring continuously while mixing.
vii) To adjust the consistency (viscosity) while applying, use specified thinners only, & should
not normally exceed 10%.
viii) Paints should be stored in a cool dry place with sufficient ventilation. Avoid fire hazards.
ix) Painting should be carried out in a well ventilated place, whether conditions at site have to be
carefully observed. Do not paints when relative humidity rises above 90% or during fog,
x) Seal the containers tightly after use. All coating shall be applied either by brush or by spray or by dipping or any other method
laid down. The painting application methods are Brushing, Spray Painting, Airless spray,
Electrostatic spray, Roller application & Dipping. The method of application will vary
according to the system or the surface size of object to be painted. Surface preparation, the
number of coats, the interval between coats, the film thickness & the workmanship will be
in accordance with the relevant specification.
| Quality of Paints: - Selection of quality paints
Before going for any painting job it is advisable to consider following aspects in
Selection type (quality) of paint.
i) The type of surface, environmental conditions & anticipated budget.
ii) For exterior or interior application the type of paints or paint system from primer to undercoat & finishing has to be carefully followed so that the system is compatible.
iii) Our company has a full range of paint products for every type of application. Chemical resisting coatings such as Chlorinated Rubber Paints, Epoxy Paints, and Polyurethane Paints & Primers are made under strict quality control & inspection.
iv) Surface preparation followed by primer is of paramount importance in optimum performance of a system. We offer vide rage of primers.
v) We also manufacture as per customer's tailor made order, shade & specifications.