The Basic of Airless Spraying

1. The Basic of Airless Spraying

2. Coating Material
4 Basic Components
 Binder, Resin, or Polymer
 Pigment
 Solvent
 Additives

3. Viscosity
Solid by Volume/Solid Content
 Low Solids = 20-30% solids
 Medium Solids = 30-50% solids
 High Solids = Up to 100% solids

4. Methods of Coating Application
Brushes Rollers Sprayers
The choice of an application method depends on the type of coating to be applied, the
type and size of surface to be coated, and governing environmental regulations. However,
the consistency of some coatings may dictate a particular method. For example, coatings
that are excessively viscous may not permit effective application by spray; or a low viscous
coating may only be effectively applied by spray. Either the specifications or the
manufacturer's instructions usually will indicate the preferred application method. All
application methods have inherent advantages and limitations.
*) other methods: electrodeposition/electrocoating (E-coat), autodeposition, dip/flow/curtain coating,

5. Brush
Methods Advantages Limitation
Brush • the ability to stripe coat
• best for oil-based and waterborne
coatings, or slow-drying coating
• most common, particularly around
irregular surfaces such as rivets, bolt
heads, piping, railing, and similar areas
• low investment, low technology
• independent of power
• it aids in thorough wetting of the
substrate, particularly on surfaces that
are porous
• can be used in restricted spaces, be
useful for small areas, with less wastage
and contamination of surroundings.
• no loss through overspray
• short set-up time
• slow, low productivity,
• labor intensive
• may not produce a uniform coating
thickness
• not practical for large surfaces
• may leave unsightly brush marks
• not recommended for fast-drying &
high solid coating (i.e. vinyl zinc-rich
and epoxy zinc-rich coatings that need
agitator to be kept in suspension
during application)

6. Roller
Methods Advantages Limitation
Roller • excellent for large, flat areas (e.g., tank
sidewalls and tops, decks, ship hulls,
walls, and ceilings) or whenever
application does not require the skill
needed for brush or spray application
• recommended for use in windy
conditions to eliminate excessive
material loss and overspray
• may be used for indoor application
when overspray cannot be tolerated.
• Twice faster than brush application
• Roller application characteristics for
high solids coatings and inorganic zinc
rich coatings are considered poor.
High performance coatings/linings for
immersion are seldom applied by
roller because of non-uniform
thickness and wicking caused by roller
nap residue.
• demands suitable rheological
properties of the paint.

7. Sprayer
Methods Advantages Limitation
Spray • speed of application
• control of film thickness
• allows the use of fast drying coatings
• uniform finish
• can be installed as an automatic process
• more cost effective in the long run
• overspray & solvent emission = health
hazard
• does not properly fill cracks or seal
most rough surfaces
• requires more skilled operator
• requires more maintenance
• medium/high investment cost
• considerably more waste, need
serious handling

8. Types of Spray Painting

9. Type Pressure Advantages Disadvantages
Air spray /
Conventional
Max 7 bar • Very good finish achieved
• Good control ability
• You can use small amounts of material
• Poor transfer efficiency: 60% waste
(overspray)
• Slow application rate
• Can only spray low viscosity paints
HVLP
(High Volume Low
Pressure)
Max 0.7 bar • Approximately 80% efficient vs. air spray
• Good paint saving
• Environmentally friendly
• Far cleaner application, & less
maintenance
• Slow application rate
• Low viscosity materials only can be
sprayed
Airless Max 500 bar • Fast application - 200 to 250 M²/hour
• Good transfer efficiency
• Application of high build coatings
• High film build
• Poor control
• Reduced quality of finish
 Incapable of partial triggering
 Susceptible to “tails”
 Fluid injection hazard
 Spray gun tip wear
Air Assisted
Airless /Airmix /
Aircoat
Max 400 bar •More control, high production rates
•Better transfer efficiency
•Better quality finish
• reduced wear on fluid nozzle and pumps
 No partial triggering
 Requires extra air hose
 Fluid injection hazard
 Susceptible to lower transfer efficiency
than airless due to improper setup of air
and fluid pressure
Electrostatic • Greatly reduced overspray
• Paint saving
• Low booth maintenance
• Labor saving
• Less spraying ability required
 Spray equipment more expensive
 Can produce minor shocks
 Electrostatics can be easily deactivated
and thereby become more inefficient
 Ungrounded areas will repel coatings
 Requires good ground, <1 meg ohm

11. X70 Light Cart
X50 X40
X70 Heavy-duty Chart

12. Why Plural Component Airless Sprayer?
• Almost 90% of today’s coating materials are plural components, but
applied with single component sprayer.
• Today’s “solventless” coatings are high in viscosity. When 100% solids
components are mixed, then cross-link to form a solid. There is no
solvent to act as a “heat sink” and slow down the reaction. Reaction
is subject to heat generation (exothermic reaction) that shortens an
already short pot life. Larger quantities generate greater heat,
leading to shorter pot life. Plural Component system are usually
equipped with heaters to reduce viscosity.
• 100% SBV or solvent-free coating material:
– Epoxy: A two-component material that mixes a base (resin or epoxy) with
an activator (catalyst, hardener, or converter).
– Polyurethane: A two-component, fastset coating formed by reacting (or
mixing) an isocyanate with a polyol resin.
– Polyurea: A two-component fast-set coating that is formed by reacting an
isocyanate with an amine resin.

13. Plural Component Airless Sprayer
The base and activator are pumped to a mixer
manifold or plural component spray gun separately.
They are then mixed and applied immediately to
the work piece via the spray nozzle.
Advantages
– Labour saving
– Material saving
– Guarantee of correct mixing
– Allows short pot life materials to be applied
Disadvantages
– Can be difficult to use

14. Plural Component Airless Sprayer
XP35 XP50
XP70
XM70
XMPFP
XM50

15. Fast Set Curing Plural Components Sprayers
Reactor E-30i
Reactor H-XP2
Reactor E-XP1

16. Plural Components Sprayers Accessories
Standard heater
(Viscosity Control)
Gun Splitter
Electric heated hose
Externally controlled Viscon
Water-jacketed Heat Hose
Complete Viscon HF Heater
with Manual Thermostat Control
Remote manifold
Mix manifold
Hopper
Heated Hose Controller
XTR 5
XTR 7
Fusion gun
Probler gun

17. Spraying is simple but you must have the right equipment
What types of materials will you spray? Now and in the future?
The types of materials you spray will determine the size of the tips you use. If you plan
to spray a variety of materials you have to consider buying a sprayer with more
versatility.
How many gallons per week will you spray?
Purchasing a part-time sprayer to do a full-time job has disappointed many
contractors. In the long run, saving money on a sprayer that is inadequate for the job,
or not durable enough, will cost a lot in lost labor.
What power sources are available? Will most jobs be indoors or outdoors?
Your answers will help choose a unit family (gas, electric, or compressed air)
based on power sources alone.
What types of surfaces will you be spraying?
Will you be spraying on drywall, exterior siding, or concrete? You have to
consider the tip sizes needed as well as the quality of finish required in order to
choose the best sprayer for the job.
.

18. Spraying is simple but you must have the right equipment
How many spray guns will you use at one time, now and in the future?
If you plan to use more than one gun at a time, then you have to purchase a unit that
has the ability to handle multiple guns.
What types of jobs will you bid?
Each job has its own requirements. New construction, maintenance work, and
commercial jobs all vary in terms of: coatings used, crew size needed, and power
sources available.
What hose lengths will you use?
Hose length depends on the job site, material being sprayed, tip size, and hose
diameter. Your sprayer must be able to support the length of hose.
How much do you want to spend on a sprayer?
Buying a sprayer is an investment. You do not want to over-buy or under-buy. Keep in
mind the cliché, “You can pay now or pay later”. Downtime resulting from an
undersized, overworked sprayer or poor quality equipment can quickly wipe out any
savings from the initial low purchase cost of the sprayer.

19. Airless Spraying Techniques
Adjusting the Pressure
It is best to spray at the lowest pressure that completely atomizes the coating. The pressure
control should be set at a low-pressure setting and slowly increased until the paint is completely
atomized. If the spray pattern has fingers or tails, then the pressure should be increased.
If the maximum pressure of the sprayer is not enough to achieve a good spray pattern, a spray tip
with a smaller orifice should be used.

20. Airless Spraying Techniques
Aiming of the spray pattern
The spray gun should be held approximately 12
inches (30.5 cm) from the surface, and aimed
straight (both horizontally and vertically) at the
surface. Extremely large tips will require you to
move further away to achieve a good
spray pattern.
The spray gun should move across the surface
with the wrist flexed to keep the gun pointed
straight at the surface. “Fanning” the gun to
direct the spray at an angle will cause an
uneven finish.

21. Airless Spraying Techniques
Triggering Technique
The spray gun should be triggered after
beginning the stroke (lead stroke) and
released before ending the stroke (lag
stroke). The gun should move during
both the trigger squeeze and trigger
release. This technique prevents
blotches of thick coating at the
beginning and end of each stroke.
Overlapping Technique
This technique ensures that an even amount of coating
has been sprayed onto the surface. The spray gun
should be aimed so that the tip points at the edge of
the previous stroke, overlapping each stroke by 50%.

22. Common Spray Technique Errors
Pressure Set to High
It is easy to just crank up the pressure control to the maximum and slap on the
material. For professional results, turn down the pressure as low as you can
without getting tails. You will:
– Reduce wear on your pump
– Reduce wear on your spray tip
– Spray a more consistent even finish
– Reduce the amount of overspray (wasted paint)
Holding Down the Trigger too Long
It is easy to just pull the trigger and keep moving up and down or side to side,
overlapping and moving down the wall spraying constantly. If you are not triggering
the gun every time you change directions you will have at least double the mil
thickness in every spot you change directions. In the right light or over time, your
customer may be able to see these heavy areas. As explained earlier, you should
trigger the gun on each stroke and be moving into and out of each trigger pull.