|
Here's what you told us:
What Kinds of Spray Painting Equipment Are in Your Plant Now?
| Type |
% of
Plants* |
| Manual, non-electrostatic air-atomize guns |
64 |
| Manual, non-electrostatic airless guns |
22 |
| Manual, non-electrostatic air-assisted airless guns |
17 |
| Manual, non-electrostatic HVLP Guns |
37 |
| Electrostatic Equipment |
42 |
| Plural-Component Equipment |
11 |
| Liquefied CO2 Application |
2.5 |
| *Total of percentages is not 100
because many plants have more than one type of spray
equipment |
The fact that such substantial percentages of the plants have
airless, air-assisted airless, HVLP and electrostatic guns shows that
finishers are intent upon improving transfer efficiency and lessening
VOCs. But conventional manual non-electrostatic air-atomize guns are
still the most versatile, used to some degree in 64 pct of the plants,
including many that have more advanced equipment.
How important is control of VOC discharge in your plant?
| Important? |
% of
Plants* |
| Extremely |
58 |
| Moderately |
27 |
| Not |
10 |
| *Percentages do not total 100 because
some respondents did not answer the
question. |
The overwhelming majority of these paint-line managers are
very concerned about discharge of volatile organic compounds. "No
kidding," you say. "Who ISN'T concerned about VOCs?" As the survey
indicates, most finishers certainly recognize the VOC problem. But it's
a matter of degree; if you are in a rural area fifty miles from nowhere,
you may be getting less heat from EPA and local authorities; or if you
paint only a few castings daily, maybe no one cares. In any case, the
survey confirms what we would have predicted: control of VOCs is a key
factor in selecting spray-painting equipment.
How important is high transfer efficiency in selecting spray painting
equipment for your plant?
| Important? |
% of
Plants* |
| Extremely |
50 |
| Moderately |
35 |
| Not |
8 |
| *Percentages do not total 100 because
some respondents did not answer this
question. |
Transfer efficiency rates the ability of spray-painting equipment to
put paint on the parts being painted rather than allowing it to escape
as overspray or in other forms of paint waste. If you spray 10 pounds of
paint on uncoated parts and those parts gain two pounds as the result of
being coated, you've achieved 20 pct TE, i.e., 20 pct of the paint ended
up on the part and the rest landed on spray booth filters, booth walls,
hangers, etc.
In selecting new spray-painting equipment, 85 pct of those who
responded rated transfer efficiency as extremely or moderately
important. Most survey respondents said cost is the reason they consider
TE so important, but in some areas of the country air-pollution-control
is an equal driving force. In these areas transfer efficiency
percentages are mandated by air-pollution-control authorities intent
upon using improved transfer efficiency to lessen VOCs. In 1989,
authorities in southern California required finishers to begin using
application equipment that met transfer-efficiency standards deemed
possible with the more advanced spray equipment.
If conventional air-atomize spray is used, it is possible that only
20 pct of the paint becomes a coating on the surfaces being sprayed, and
80 pct is wasted. And the paint isn't the only cost associated with poor
transfer efficiency. Spray-booth-cleanup costs often equal the cost of
the paint. Plus the fact that you may end up with waste that is either
difficult or very expensive to dispose of.
What have you done in the past five years to improve transfer
efficiency and/or lessen VOC discharge?
| Installed |
% of
Plants* |
| HVLP |
38 |
| Electrostatic |
29 |
| Paint Heaters |
15 |
| Voltage-Block |
3 |
| CO2 |
2 |
| *Percentages do not total 100 because
some plants have installed more than one type of equipment while
others have installed no new
equipment. |
If you're like most paint-line managers you've already made
significant changes that improve transfer efficiency and/or lessen VOC
discharge as shown above. You've bought new equipment, changed to
coatings that contain less VOC, or both.
Have you replaced some or all of your spray-painting equipment with
powder coating equipment? Do you plan to do so in the next two years?
| Answer |
% of
Plants |
| Yes |
26 |
| Plan to in next 2 yrs |
15 |
As the survey shows, replacement of some or all of the surveyed
plants' spray-painting equipment with powder-coating equipment has been
taking an ever-increasing share of the market for equipment that
improves TE and lessens VOCs. Taking into account the fact that we
purposely excluded from this survey all plants that apply powder
coatings and not liquid coatings, this is an impressive change. The
number of plants that have already installed powder coating equipment
would be even higher if those that now apply powder only had been
included.
Is most of your coating done with
| Type of Coating |
% of
Plants* |
| Solvent-Thinned Coatings |
54 |
| Powder Coatings |
23 |
| Waterborne Coatings |
20 |
| UV Cured Coatings |
1 |
*Does not total 100.
Some recipients
did not reply to this
question. |
Despite all the pressure to eliminate VOCs, more than half the spray
painters who responded to this survey still use coatings thinned with
organic solvents. Undoubtedly some of these are higher-solids coatings,
though we did not attempt to quantify this. But it is quite evident that
many plants have requirements that make it difficult or too expensive to
change from their "tried and true" conventional-solvent-thinned
coatings. For some it is a matter of meeting customer specifications or
their own specs. Others are hesitant to make changes that might
compromise product quality or appearance, while still others paint
configurations that may be difficult to coat with certain types of
equipment that lessen VOCs and improve transfer efficiency.
Nevertheless, as environmental regulations tighten and finishers
continue to search for ways to cut costs, the trend is clearly toward
alternative coatings. Indeed, 43 pct of the finishers surveyed said most
of their spray coating is done with powder coatings or waterborne
coatings.
Many applicators of liquid coatings who do not now use waterborne
coating materials may be forced to do so in the future, as authorities
require lower VOCs.
Low-VOC waterbornes offer code compliance but are more sensitive to
shearing, air entrapment and settling than are solvent-thinned coatings.
These characteristics can lead to degradation and inconsistency of
viscosity and variations in flow rates. Finish quality suffers as a
result.
With these facts in mind, you should buy equipment that helps to
avoid the aforementioned problems, even if you are presently continuing
to use solvent-thinned coatings. By purchasing waterborne-compatible
equipment, with wetted surfaces made of stainless steel or other
corrosion-resistant materials, you build in flexibility for the future.
What kinds of spray painting equipment do you plan to buy over the
next five years?
| Type of Equipment |
% of
Plants* |
| Manual, Non-Electrostatic** Guns |
34 |
| HVLP Guns |
25 |
| Electrostatic Equipment |
22 |
| *Does not total 100 because some plants do not plan
to buy while others have plans to buy more than one
type. |
| **Includes air-atomize, airless and air-assisted
airless guns. |
How many spray booths are in use in your plant?
| Number of Booths |
% of
Plants* |
| 1 |
27 |
| 2-5 |
49 |
| 6-10 |
15 |
| 11 or more |
7 |
| *Does not total 100 because some respondents did not
answer this question. |
We asked this question to give you an idea of the sizes of the plants
surveyed. A total of 117 respondents work in installations with between
two and five spray booths. That's 49 pct of those who responded. Many of
these finishers 64 pct to be exact are in plants that have between two
and ten spray booths. Seven pct are very-high-production installations,
with 11 or more spray booths.
Is some or all of your painting done on conveyors?
57% of the plants have conveyors. This is another
question related to the sizes of installations.
Spraying, TE and VOCs
Most of the alternatives to conventional air spray guns would never
have been invented had it not been for the relatively poor transfer
efficiency of air-atomize spray. Two of the most common replacements
electrostatic application and airless spray were commercialized long
before the advent of the Environmental Protection Authority (EPA). The
driving force was to reduce overspray (and cost of paint). There was
certainly room for improvement, since conventional air-spray guns can
waste 60-80 pct of the paint purchased.
The major types of spray equipment in use today are as follows:
- Conventional Air-Atomize Guns
- Airless and Air-Assisted Airless Guns
- High-Volume, Low-Pressure Spray Equipment
- Electrostatic Spray Equipment
- Plural-Component Spray Equipment
Conventional Air-Atomize Spray Guns
These are "conventional" because they have been around since the early
part of this century. They were widely used before any of the others.
Basically they emit a stream of paint from a small opening in a fluid
nozzle. The paint is broken up into tiny droplets by compressed air
emerging from jets adjacent to the fluid nozzle. Relatively high air
pressures at low volumes will quickly atomize large amounts of paint.
Despite their tendency to spray more paint on booth filters than onto
parts, they remain an important tool in most painting facilities. Why?
Because they are so versatile. They can spray a class A finish at high
speeds on almost any surface that needs to be painted. So even if you have
one of the more efficient types of spray apparatus, you probably still
need a few conventional air-atomize spray guns to do what the more
advanced equipment will not.
Advantages
- In the hands of a skilled operator, produces smooth, reflective
finishes.
- Can be used to coat almost any shape. Using a variety of fluid and
air nozzles, an operator can spray narrow bands or wide fan patterns.
- Can apply paint at high production rates on parts hanging from
fast-moving conveyors.
- Are "user friendly." Most spray painters are experienced in using
them.
Disadvantages
- Very poor transfer efficiency. Wastes paint, increases cleanup
costs, emits more VOCs.
Airless Spray Guns
When you think of airless spray, think of a garden hose. It sprays
water under high pressure through a nozzle. When the water emerges from
the nozzle its velocity causes the stream to disintegrate into droplets as
it encounters resistance from the atmosphere. The airless paint gun is
similar in that it pressurizes paint to 900-1200 psi (or higher) and
forces it through a nozzle. Unlike conventional air spray, there are no
jets of atomizing air to break up the paint and propel it to the surface.
Atomization is dependent upon high fluid pressure.
Advantages
- In the absence of atomizing air, less overspray and better transfer
efficiency.
- Can apply paint at high flow rates, resulting in ability to meet
high-production speeds.
Disadvantages
- Inability to break up paint into very fine droplets, thus producing
a coarser spray and a rougher finish.
- Nozzle wear. High velocities cause abrasive pigments in paints to
wear nozzle openings more rapidly as they travel through the nozzle.
- Danger of airless-injection injury. The paint emerges with such
force that it can penetrate skin exposed to the spray at close range.
Air-Assisted Airless Spray
A hybrid of airless spray and conventional air-atomize spray, this kind
of gun uses fluid pressures higher than those used in conventional
air-atomize guns but lower than those employed in normal airless spray.
Unlike normal airless guns, these guns do have compressed air jets that
supply atomizing air, but the air pressure is far lower than that used in
conventional air-atomize guns. The result is that the coarse spray
provided by the airless atomization is further broken up into a finer
spray by the compressed air.
In operation, air-assisted airless guns provide atomization much better
than is normal with airless spray. Some suppliers of this type of
equipment claim that finish quality and productivity equal that produced
by air-atomize spray. Danger of airless injection is lessened, as is wear
of fluid nozzles.
The main reason for considering use of air-assisted airless spray,
however, is its much better transfer efficiency. The softer spray also
makes it easier to spray into recesses.
Both air-assisted and pure airless spray operate at high fluid
pressures and thus can use smaller-diameter fluid lines. This translates
into paint and solvent savings. The reason is that it takes less solvent
to flush smaller-diameter lines. One manufacturer reports a study showing
that by replacing a 25-ft, 1/4-inch-diameter hose with a 20-ft
3/16-inch-diameter hose, the reduction in paint and solvent waste was 100
gallons per year.
High-Volume Low-Pressure (HVLP) Spray
HVLP is a variation of conventional air-atomize spray. The difference
is that these guns are designed to atomize paint using a high volume of
air delivered at low pressure. The lower pressure results in far less
overspray and "bounce-back."
Advantages
- Better transfer efficiency results in less paint waste and lower
cleanup costs. The exact TE depends upon the circumstances in your
installation the booth design, spray techniques, the mix of parts, etc.
But most experts agree that HVLP offers significant improvement.
- Operators used to conventional guns generally find it easy to learn
how to use HVLP.
Disadvantages
- Atomization may be insufficient to meet the strictest requirements
for smooth, fine finishes.
- May be difficult to atomize paint at sufficiently high rates to meet
very high-production requirements. HVLP atomization capability has
improved markedly in recent years, however, with better ability to break
up low-VOC coatings being sprayed at high fluid-flow rates.
Some problems in achieving proper atomization with HVLP may be caused
by "starving" the spray gun for air. Causes of this problem include use of
air hoses that are too long or too small in diameter; use of too many
"quick-disconnect" fittings; and use of low-performance air compressors
and air regulators. Any one of these factors may result in too little air
being delivered to the air cap, causing poor atomization from the gun.
Some of these guns use air compressors to deliver the atomizing air,
while others use a turbine. The turbine is a series of fans mounted inside
a housing, designed to produce pressurized air for one or more guns. In
the process of forcing the air through the turbine the fans create
friction and warm the air. This helps to heat the paint and in turn lowers
its viscosity, thus making it easier to atomize.
Electrostatic Painting
Electrostatic painting begins with a spray gun or other device (discs
or bells) to atomize paint. The atomizing principle could be any of those
previously discussed conventional air-atomize, HVLP, or airless.
The difference is that an electrostatic application device is equipped
with a means of electrically charging the particles of paint. A common
method is to build in an electrode near the point where paint is atomized.
This electrode electrostatically charges the particles negatively. Parts
are grounded, usually by hanging them on a conveyor securely connected to
a ground. The grounded parts attract the negatively charged paint
particles (opposites attract).
The result is that fewer of the paint particles are propelled into
space as overspray and more are electrostatically guided to the surfaces
of the parts being painted. Sprayed particles will even turn the corner
and be attracted to the back side of a part if the velocity of the
particles causes them to initially travel past the parts being painted.
This is called "wraparound."
Transfer efficiency is greatly improved. The amount of improvement
depends upon the parts being painted, the booth design, etc. Electrostatic
spray is particularly beneficial in improving TE when parts with lots of
open areas lacy patterns, for example are being sprayed.
Advantages
- Higher transfer efficiency.
- Coverage of edges (electrostatically guided paint is attracted to
high points and edges first).
- Uniformity of film thickness. As paint builds up on surfaces with
the highest electrostatic attraction, it insulates them. Then electrical
attraction increases in the uninsulated, uncoated areas, and these
receive more of the paint.
- Productivity. Electrostatic guns mounted on reciprocators are widely
used to paint long runs of parts in high-production installations. Labor
costs are lower.
Disadvantages
- Faraday-Cage Effect. As we said, electrostatically charged particles
seek out the nearest grounded surface. If that happens to be the ridge
area of a sculptured part, the valley may be difficult to reach. For
this reason, manual touchup with non-electrostatic guns may be
necessary.
- Changes appearance of metallics. Many paints, especially those used
in automotive finishing, contain metallic flakes that give the finish a
metallic sparkle. The visual effect is different if the particles are
applied electrostatically, since they are conductive and tend to stand
on edge rather than lie flat in the coating. This can be a problem,
since auto-repair shops generally use non-electrostatic spray, which
produces a different visual effect.
- Fire hazard. In an electrostatic installation not properly set-up,
there is danger that a spark can occur, igniting paints containing
flammable solvents.
- Safety. If operators are not careful to follow set-up directions,
they can be electrically shocked.
- Ergonomics. Electrostatic guns traditionally have been longer and
heavier than conventional guns. Some have a bulky cable connected to
them to carry the electrical current. Operators may find some guns more
difficult and more tiring to handle. But suppliers have been working to
improve ergonomics of electrostatic guns. In considering this equipment
(and indeed any spray equipment) you should look not only at size and
weight of the gun, but evaluate ease of trigger pull and maneuverability
of the tool (with hoses) as well.
- Cleanliness. It's always a good idea to keep spray booths,
conveyors, and spray equipment clean. But in electrostatic painting it
is not just a good idea; it's mandatory in order to achieve the benefits
of electrostatic application. Parts must be securely grounded as they
travel through the booth. This means that if they are hanging from
paint-laden racks or the conveyor has picked up paint and is becoming
insulated, electrostatic attraction is lessened.
- Some coatings may require reformulation. Since the process depends
upon electrical conductivity or lack thereof, solvent selection becomes
more important. Some solvents are more conductive than others. In a like
manner, application of waterborne coatings requires special equipment to
deal with the conductivity of water (more about this later). High
humidity in the paint booth also can cause conductivity problems.
Electrostatic Rotational Atomizers
Rotary atomizers utilize centrifugal force rather than compressed air
or fluid pressure to atomize paint.
Discs. Imagine a spinning flat round disc with a hole in the
center. Feed paint through a hose so that it overflows through the hole
and onto the spinning disc. Centrifugal force propels paint over the
surface of the spinning disc until it flies off the edge. The paint
atomizes as it is propelled through the atmosphere. Add electrostatics and
one has an electrostatic spray-painting device.
Parts on hangers travel around the periphery of the disc in an "omega
loop," housed by a circular spray booth. The disc spins and simultaneously
moves up and down, on a floor- or ceiling-mounted reciprocator. As the
parts travel around this loop, paint particles are being propelled toward
the parts and electrostatically attracted to them. Since the disc moves up
and down, the entire length of a long part or racks of parts is painted.
Bells. Electrostatic bells are similar in principle, except that
in this case the paint is fed through a hole at the closed end of the
spinning bell-shaped atomizer. Centrifugal force propels paint from the
edges of the bell. Bells may be mounted on reciprocators or on hand-held
guns.
Higher-Speed Rotational Devices. The latest bells and discs
utilize higher rotational speeds, producing finer atomization, the ability
to apply higher-solids and waterborne coatings, and high transfer
efficiency. These devices are often mounted on reciprocators in
very-high-production installations. Less operator time is required in the
disc application itself, so labor is conserved.
But high-speed discs and bells also may have problems in reaching into
deep recesses (Faraday-Cage areas). Thus some of the labor conserved by
their use may be required to hand-spray reinforce the areas of parts not
properly covered by the automatic spray.
Voltage-Block Systems
Waterborne coatings are widely used to
lessen the VOC content of coating materials. To oversimplify, if water
replaces some or all of the organic solvents used in paints, the resultant
coating material contains less VOC.
Electrostatically applying waterborne coatings can be a problem, in
that their water content increases their electrical conductivity. Unless
special precautions are taken, the waterborne coating provides a
conductive path from the electrostatic applicator to the grounded paint
supply.
To circumvent this, manufacturers have developed increasingly
sophisticated "voltage-block" systems. These electrically isolate the
spray applicator and prevent high voltage from following the conductive
path through the paint-supply line to the waterborne coating supply.
Switching to waterbornes is now easier because of the new technologies
available in voltage-isolating systems. Waterbornes can be
electrostatically applied safely, economically and in minimum floor space
(newer voltage-block systems eliminate the need for isolation cages to
deal with the conductivity of waterbornes).
One supplier urges finishers to look carefully at the latest
technologies for electrostatic application of waterbornes. "There are
several emerging technologies that make this switch more plausible and
less costly," he says.
Another supplier claims that some HVLP guns have advantages in
waterborne application because they supply heated atomizing air, which
provides faster set-up times and improved drying of waterborne coatings.
Plural-Component Guns
Some coatings, principally urethanes,
are supplied as two components. After being mixed, the components
chemically react with one another to form a solid coating. They are often
referred to as "catalyzed" since the "catalyst" causes a reaction that
leads to curing of the coating. An advantage is that low temperatures are
sufficient to cure the coating and thus plastic parts that cannot tolerate
high temperatures can be coated. The coatings also exhibit unusual
durability in certain applications and require less solvent for thinning,
thus improving VOC control.
If the two components are mixed before entering a paint pump or
pressure pot, the mixed material must be sprayed promptly or the reaction
of the two components increases viscosity to the point where the coating
is no longer sprayable. It is said to have limited "pot life."
For this reason, spray guns have been developed that bring each of the
two components into the spray gun through separate feed lines. The
components mix just prior to application. This remedies the "pot-life"
problem, since mixing occurs only at the moment before application.
Two-component application equipment is used in some very
high-production applications, but as the survey shows, it is not used to
the extent of the more conventional technologies. The reason is obvious
the equipment is more costly, as are the coating materials.
CO2 Spray
The most recent development in
spray application equipment is built to spray coatings formulated with
heated, compressed carbon dioxide. In this form carbon dioxide is a liquid
and can be used as a paint thinner. When the coating is sprayed the
liquefied carbon dioxide is no longer compressed and reverts to a gas.
Since carbon dioxide is naturally present in the atmosphere and is not
considered hazardous, it is interesting to finishers searching for
alternatives that lessen VOCs. The system was developed and patented by
Union Carbide under the trade name "Unicarb."
Thus far CO2 spray has been used in a few
commercial applications, as the survey indicates. But this is a relatively
recent development, and its use may proliferate in coming years.
Hybrids
When you consider combinations of the technologies
for spray painting, there are additional possibilities. One can add
electrostatics to almost any of the basic spray-application technologies,
for example.
Such technologies as HVLP and air-assisted airless, already more
efficient in raising TE, can be equipped with electrostatics to further
improve TE and lessen VOCs. But you have to test any system that appears
to meet your requirements in YOUR plant, while painting YOUR mix of parts.
Paint Heaters
Heat reduces the viscosity of paint. Heating
paint before it is atomized makes it possible to spray more viscous paint.
In some cases it is possible to use paint containing less solvent, since
not as much is required to lower paint viscosity. Obviously less solvent
in the coating material equals lower VOC content. Thus paint heaters are a
well-established, viable means of lowering VOCs. They are probably
under-utilized. If the coating formulation permits use of a paint heater,
it will keep viscosity more constant, improve TE, lower wear of equipment
and improve finish quality and consistency.
Trends
Manufacturers of spray equipment are constantly
innovating to produce guns, bells and discs that are better able to apply
waterborne and higher solids coatings. The latter require higher air and
fluid pressures for proper atomization, but a careful balance must be
struck to keep from defeating the purposes better transfer efficiency and
lower VOCs. Hand-held guns that are lighter in weight and easier to
trigger are increasingly important in preventing work-related injury.
You face an almost bewildering array of equipment and materials offered
by suppliers to improve transfer efficiency and lessen VOCs. To measure
TE, count the number of parts or square feet painted at a given film
thickness, per gallon of paint from a pressure pot; or use a flow meter to
determine how many ounces flow from your pumping device. Do that for every
type of spray equipment being evaluated.
You also have to look at your specifications for film thickness,
coating composition, appearance and corrosion resistance. Consider needs
for color change, spraying odd shapes, speed of production, operating and
materials costs, and capital-equipment budgets. Rate ergonomics, so that
your spray painters are comfortable with the guns they operate and not at
risk of electrical shock, fire hazard or repetitive-motion injury. And
after you've done all that, you still may be forced by local or federal
regulations to make some changes just to comply with your permit.
The survey results reported here give you a good idea of what others
have been doing to improve TE and lessen VOCs. They've been busy switching
to:
- Electrostatic Spray
- HVLP
- Air-Assisted Airless Spray
- Powder Coating
- Waterborne Coatings
- High-Solids Coatings
Convertible Air-Spray Guns. As the survey indicates, many of you
continue to use conventional air-atomize spray guns, and you plan to
replace these guns as they age. If you're concerned about EPA regulations
tightening, however, you might consider conventional air-spray guns that
are made to be converted to HVLP. By inexpensively changing a few
components of these guns, one can move to HVLP without buying a whole new
gun.
Operator Training
Training operators of spray equipment has
always been important, but it becomes even more so when one considers how
operators' techniques can influence TE. Operator training and annual
re-training may be the best investment you can make. Knowledgeable
operators with good spray techniques can measurably improve TE without
changing equipment.
Pressures. Operators sometimes perceive that they can increase
air and fluid pressures to improve speed or reduce orange peel. Had they
used the right air caps and fluid tips they might have applied a smoother
finish at lower fluid and air pressures. As much as 20 pct of the paint
you apply can be wasted by too-high fluid and air pressures. Use the
lowest pressures consistent with finish quality and productivity. It's
worth some experimentation to find the optimum combination of fluid tips,
air caps and pressures. Begin lowering pressures and see how far down you
can go while maintaining finish quality.
Exhaust Rates. In trying to improve transfer efficiency plant
engineers must set air-exhaust rates in spray booths to the lowest
consistent with operator safety and comfort. Too-high rates can pull more
paint onto air-exhaust filters than is being applied on parts being
painted. OSHA regulations specify minimum flow rates and you should aim to
be close to these rates.
Gun Handling. A well-trained operator holds the gun
perpendicular to the surface being painted, at a distance of six to eight
inches. He avoids "arcing" (holding the gun at less than a 90-degree angle
to the surface). Holding the gun at a 45-degree angle to the surface, for
example, wastes 65 pct of the paint.
Good operators move the spray gun toward the surface to be painted
before triggering. Just as they reach they edge of the surface, they
trigger to begin applying paint. Then as they reach the end of the surface
being painted, they release the trigger to stop paint flow. Lots of paint
can be wasted by sloppy triggering.
Manufacturers of equipment have been paying much more attention to
ergonomic design, particularly low trigger-pull force and ease of holding
and moving guns. Companies using ergonomically designed guns report not
only greater worker satisfaction and higher-quality finishes, but actual
improvements in TE, resulting from proper triggering and gun motion.
A competent operator learns how to overlap his strokes to apply a
smooth finish without excessive thickness. The objective is to apply an
even coating of the specified thickness. Too-thick coatings waste paint
and increase VOCs.
Your equipment and coating suppliers can help you with operator
training and tell you where to find training courses for your operators.
PF
Acknowledgments
Products Finishing acknowledges
information provided by the following sources:
- "Industrial Painting: Principles and Practices," by Norman R.
Roobol, available from Hanser
Gardner Publications, 6915 Valley Ave., Cincinnati, OH 45244-3029,
for $49.95, postpaid.
- Carl Izzo, consultant and Products Finishing columnist, 2245
Manordale Dr., Export, PA 15632.
- Accuspray, 23350 Mercantile Rd., Cleveland, OH 44122-5939.
- Binks Manufacturing Co., 6915 Belmont Ave., Franklin Park, IL
60131-2887.
- Can-Am Engineered Products, Inc., 30850 Industrial Rd., Livonia, MI
48150.
- Graco, Inc., PO Box 1441, Minneapolis, MN 55440-1444.
- ITW DeVilbiss, 1724 Indian Woods Circle, Maumee, OH 43537.
- ITW Ransburg Electrostatic
Systems, 320 Phillips Ave., Toledo, OH 43612-1493.
- Kremlin, Inc., 201 S. Lombard Rd., Addison IL 60101.
- Lex-Aire Spray Systems, 34 Hutchinson Rd., Arlington MA 02174.
- Nordson Corp., Liquid Systems
Group, 555 Jackson St., Amherst, OH 44001.
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