Spray Painting
Basics of Spray Painting:
Spray painting
is a process of using a spray painting device in order to paint
a coating such as paint,varnish,ink onto a surface. The painting surface
could be either an indoor or an outdoor surface ranging from furnitures,houses
to cars,trucks.Now-a-days spray painting is widely used in graffiti. Some
objects like wrought-iron lawn furniture, screens, metal fencing etc that
would be difficult to paint with a brush or roller are ideal candidates
for spray painting.Infact just about anything could be painted using spray
painting!
Spray Painting Equipment:
The main equipment
used in spray painting is the air spray gun.
There are two different types of air gun spraying: the manual operation
method and the automatic process. In the manual method the air
gun sprayer is hand held and moved forward and backward over the
surface, each stroke overlapping the last which ensures a continuous coat.
In the automatic process, the gun head is fixed to a mounting block,which delivers
a stream of paint from this position.
The Equipments and the Techniques used in spray painting are described
here:
1. HVLP(High Volume Low Pressure): This is similar to the
common spray gun in that it uses a compressor to supply the air.The spray
gun itself needs low pressure (LP) and a higher volume (HV) of air in order
to aerosolize and propel the paint at a lower air pressure.HVLP Spray Gun
Systems are
most commonly used in the automotive, furniture finishing as well as in
the cosmetic industry.
2. LVHP(Low Volume and High Pressure): Utilizes a lower volume of air to atomize the paint .These spray guns, like HVLP systems, function at low pressure but also possess a low volume of paint coating and is utilized with a smaller compressor. These spray gun systems are utilized generally in small shops.
3. Electrostatic: Electrostatic painting occurs when an electrically charged powder is sprayed on a surface which is charged with the opposite electrical charge.The whole is then baked to properly attach paint. It's more durable than liquid paint and it's an environmentally friendly process as there are no solvents that evaporates into the air or goes down the drain.Electrostatic painting is used in order to paint vehicles and office equipments.
4. Airless Spray Guns: Airless Spray Guns are attached
to a high pressure pump to atomize the coating using different tip sizes
to reach desired atomization.Airless spray gun coatings penetrate better
into pits and also possess a thick wet coating which reduces the number
of applications.Their applications are used in industrial as well as chemical
fields.
Other painting equipments include Electric fan, Automated Linear Spray Systems, Automated Flatline Spray Systems
Spray Painting Tips for beginners:
- Start with a few spray cans of paint. Though some may disagree with this, it is an
inexpensive way to check how spray painting is different than applying paint using a brush or roller. -
Ensure that the surface on which you would be applying spray paint is clean, dust-free and dry.
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Best result are obtained if you spray the paint with the temperature between 50 - 90F.Avoid painting in excessive humidity above 85 percent.It is not a good idea to spray paint if it is windy or there is dust in the air.The dust will settle on the wet paint,which will greatly affect the painting.
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The trick to spray painting is thin coats of paint and keeping the spray paint nozzle moving. Do not stop your hand and allow paint to build up in one spot.
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Hold the spray-paint can 10 - 14 inches away from the surface being painted. Make even side-to-side movements never stopping.
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Once you are finished using a can of spray paint, hold it upside down and push on the nozzle. Hold the nozzle down until no paint comes out of the tip.This action clears paint from the nozzle so the spray paint can be used in the future.
LVLP system
Types of nozzles and sprays
