vvEPA
United States
Environmental Protection Agency
Design for the Environment, Auto Refinishing Shop Project
EPA744-F-00-014
July 2000
HVLP SPRA Y GUNS IN THE A UTO REFINISHING SHOP:
A SUCCESS STORY
Every auto body shop wants to use paints efficiently,
save money, and work safely. No shop wants to take
a chance on the quality of a finish and have to redo a
paint job. And there lies the promise and challenge
of HVLP (high-volume low-pressure) spray guns.
Capable of greatly increasing paint transfer
efficiency, decreasing costs, and creating a healthier
workplace, the HVLP spray gun seems an obvious
choice. Yet many painters have been slow to switch
from conventional guns, objecting to the feel of the
HVLP spray gun and its spraying performance,
especially when applying clear coat.
Recently, as part of its Auto Refinishing Shop
Project, the U.S. Environmental Protection Agency
(EPA) Design for the Environment (DfE) Program
visited Wiley's Auto Body, Inc., a small shop near
Philadelphia, PA. Wiley's Auto Body took on the
challenge of the HVLP spray gun-and through the
initiative of the shop's head painter, Jeff Aigeldinger,
and active support of shop owner, Herb Wiley-came
up with a technique that produced great results for
them and should for you too!
Why HVLP Spray Guns? Research demonstrates
that HVLP spray guns can achieve far greater transfer
efficiency (over 60% with good technique) than
conventional spray guns. Higher transfer efficiency
means less of what you don't want: paint overspray,
mists that a painter might breathe, emissions to the
community—and more of what you do want: savings
on paint and an improved bottom line (see section on
Iowa's STAR program and cost savings).
Higher transfer efficiency eliminates pollution at its
source and is especially important from a health and
safety standpoint. Paints and coatings contain many
potentially harmful chemicals-including isocyanates,
solvents, and pigments (see sidebar on Isocyanates).
Concern for air quality from releases of volatile
organic chemicals (VOCs), like paint thinners, have
prompted several state and local governments,
Pennsylvania and the Cities of Philadelphia and
Design for the Environment Auto Refinishing Shop
Project
In its Auto Refinishing Shop Project, U.S. EPA's Design
for the Environment (DfE) program works with auto
refinishers to identify and adopt safer, cleaner, and more
efficient practices and technologies.
EPA's project team has uncovered many examples of
health and safety improvements that increase efficiency
and can help shops save money—some are even cost-free.
Other factors—like the quality of the refinish job and
environmental regulations—may also provide incentives
for change.
If you're interested in participating or would like to learn
more about this project, please call Mary Cushmac at
202-260-4443 or David Di Fiore at 202-260-3374, or
visit the DfE Web site atwww.epa.gov/dfe.
For a virtual auto body shop experience, filled with
helpful health, safety, and efficiency information, visit
www. ccar-greenlinks. org. The virtual auto body shop is
a joint product of DfE and the Coordinating Committee
on Auto Repair.
Chicago among them, to require auto refinishers to
use HVLP spray guns.
Because of the health and efficiency advantages of
HVLP spray guns and advances in technology that
have made them easier to use, awareness of the guns
has spread throughout the industry. Nonetheless,
many painters won't give up their trusty old guns:
some want proof that a HVLP spray gun can match a
conventional spray gun's top quality finish, especially
on clearcoats-without extra rubbing and buffing;
others are searching for a reliable way to make the
HVLP spray gun work well for them; and still others
simply prefer to stay with what they know and like.
The Successful Switch to HVLP Spray Guns at
Wiley's Auto Body, Inc. For years, Jeff Aigeldinger
swore by his SATA Jet 90. Its superior atomization
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of materials gave him a consistently top-notch finish
and helped him earn a reputation as a master auto
refmisher. So, when HVLP spray guns came along
Jeff was interested in the benefits, but skeptical that
the HVLP spray guns could equal the performance of
his conventional spray gun: "I just couldn't imagine
that any other gun stood a chance against the Jet 90."
Nevertheless, the promise of improved transfer
efficiency and a healthier workplace led him to
experiment with HVLP spray guns. Jeff also wanted
to get ahead of the regulatory curve, "I knew that regs
banning conventional guns were on the way-so why
wait?" The transition to HVLP spray guns for
priming and basecoat was relatively easy, but he just
couldn't achieve a satisfactory result for the clearcoat.
Consequently, Jeff found himself juggling two gun
types—typically shooting primer and base with HVLP
spray guns, always going with a conventional spray
gun for his clear finish.
A Second Look Things went on this way until two
events—the birth of his second child and a visit from
EPA's Design for the Environment—altered his
routine and prompted Jeff to take another look at the
HVLP spray gun, for the clearcoat and all his
spraying. DfE reminded him about the serious health
issues at stake and the opportunity to save paint and
reduce pollution. His second child reminded him
how much he wants to be in good health to enjoy his
children as they grow up—and his grandkids too!
As a first step, Jeff contacted his shop's paint
distributor, Sikkens, to see what they knew about
HVLP spray gun performance and if they had any
advice for applying clearcoat. "What the Sikkens rep
said to me," Jeff recalls, "is that success with the
HVLP spray gun boils down to getting the right air
pressure at the spray gun tip." For clear coats, the
spray gun manufacturer recommends 10 psi. The
Sikkens rep loaned Jeff an air cap pressure gauge,
with gauges to measure pressure on each side of the
nozzle.
When Jeff tried the pressure gauge with the shop's
regular air hose, he had to significantly increase the
air pressure going to the spray gun to get 10 psi at the
gun tip. Jeff s solution: a new air hose with a larger
inner diameter (-3/8 inch i.d.), which increased the
volume of air to the spray gun. "With the new hose,"
Jeff explains, "I was able to lower the pressure at the
Isocyanates, the hardener in clearcoats and many
primers, may be extremely hazardous to humans in very
small quantities. Isocyanates are the leading cause of
occupational asthma, a potentially life-threatening
disease. Scientists estimate that 5 to 20% of the
population may be allergic (or "sensitized") to
isocyanates. Allergic reactions include: itching and
watery eyes, skin rashes, asthma, and other breathing
difficulties.
Unfortunately, you won't know if you're allergic to
isocyanates until/unless you start experiencing the
symptoms-which can appear at first contact or at any
time. Even if you're not allergic to isocyanates, they may
still irritate your skin and lungs, and many years of
exposure can lead to permanent lung damage and
respiratory problems. If you are allergic, even tiny
amounts of isocyanate can trigger a severe lung reaction.
A sensitized painter or technician cannot work in an auto
refinishing shop without putting his life in jeopardy.
What does it all mean? Do everything you can to limit
your exposure to hazardous paint materials. An HVLP
spray gun is an important tool for reducing overspray and
painting safely.
regulator from 120 to 70 Ibs. and still keep the gun
tip pressure at 10 psi."
HVLP All the Time. In a test run with new hose
and pressure gauge, Jeff adjusted the gun settings
until he got the proper spray
pattern and atomization
with 10 psi at the spray gun
tip—then he locked in those
settings for that spray gun.
Jeff also used the pressure
gauge to calibrate his other
HVLP spray guns. To
avoid changing tips, he uses
a different HVLP spray gun
for each application-
primer, basecoat, and
clearcoat. (Note: Jeff only
used the pressure gauge to
calibrate his spray guns, he
does not paint with the
gauge on the spray gun.)
Photo provided
courtesy ofSATA
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With all his spray guns correctly calibrated, it did not
take Jeff long to get comfortable using the HVLP
spray gun for all his spraying. Within a few weeks,
his clearcoat finishes rivaled those from his
conventional spray gun—with no additional buffing.
"There is a learning curve," Jeff is quick to remind,
"the conversion doesn't happen over night. It may
take a typical painter two to four weeks to be at ease
with the HVLP spray gun and to achieve high-quality
results."
But the effort is well worth it. One big payoff: Jeff
estimates that paint usage at Wiley's is down 30% on
a per car basis. "The number is real," Jeff says, "but
painters must remember to mix less paint for the
HVLP spray gun. You're used to mixing a certain
amount of paint for a conventional spray gun and you
have to remind yourself to mix less or you'll just
wind up with leftover paint and no savings." And
beyond the savings, there's an even bigger payoff:
peace of mind. "I sleep better at night," Jeff
declares, "knowing that I've done something
important to protect my health, reduce pollution, and
improve my shop."
To ensure maximum transfer efficiency and high-
quality results with his HVLP spray guns, Jeff has
had to make some minor adjustments to his spray
technique. Specifically, he has decreased the
distance between the spray gun and the target (down
to 4-6") and slightly increased the speed of his
stroke-technique changes each painter will discover
as he works with the HVLP spray gun. As always,
Jeff ensures the best transfer efficiency by keeping
his spray gun square with, and at a consistent-
distance from, the target surface throughout his
stroke.
Thanks to Jeffs efforts, Wiley's Auto Body, Inc.
now uses HVLP spray guns 100% of the time.
Follow-up. About a year after he first calibrated the
spray guns, Jeff used the gauges again to check the
pressures at the spray gun tip. Jeff detected a slight
shift in the pressures, an important reminder of the
need for periodic checks and setting adjustments to
ensure the best performance from the HVLP spray
guns and a consistently high quality finish.
Information on Spraying with HVLP Spray Guns
from Iowa's STAR Program. The Spray Technique
Analysis and Research (STAR) program, at the Iowa
Waste Reduction Center, has thoroughly researched
spray painting with HVLP spray guns. Based on its
research, the STAR program has learned that many
variables can influence transfer efficiency-and
potential paint savings. Variables that the painter can
control include: paint mixture content, spray
equipment type, spray equipment maintenance, and
spray technique (including pressures settings, spray
distance, and spray angle).
The STAR program and HVLP spray gun
manufacturers typically suggest an operating pressure
of about 10 psi at the gun tip. The STAR program
has observed that spraying at the manufacturer's
recommended pressure setting will decrease paint
overspray and improve finish quality. Droplet size, in
particular, has an important effect on finish quality.
STAR recommends that painters look closely at the
size of droplets near the spray edge. If the droplets
are too large or coarse, the finish won't be smooth.
Possible solutions: more air pressure, less fluid, or a
smaller fluid tip.
Key Elements for Success with HVLP Spray Guns
Ensure 10 psi at the Spray Gun Tip
D Use air hose with inner diameter of 3/8 inch
D Measure air cap pressure with gauges for your
specific spray gun (available through your gun
distributor)
Adjust Technique
D Come in closer to car surface (remaining square
with the target)
D Slightly increase the speed of your stroke
Work with the Spray Gun for a Few Weeks - and
Enjoy the Benefits!
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The following example from the STAR program
provides an estimate of material and cost savings that
a typical shop could achieve using HVLP spray guns
and proper spray technique.
Success with HVLP spray guns Is Within Reach
Jeffs experience at Wiley's Auto Body shop offers a
real-world example of how to make HVLP spray guns
work effectively for all spray applications. With
some simple equipment, a hose and pressure gauge,
and a few weeks of on-the-job practice, the health,
environmental and economic benefits of the HVLP
spray gun can be yours. Equipment manufacturers,
jobbers, and paint manufacturers have resources and
training opportunities to help painters make the
switch. Don't delay. Doing the right thing for
human health and the environment, is the right thing
for your business too.
Example of Cost Savings Using an HVLP Spray Gun
Transfer efficiencies1
Conventional spray guns: 40%
HVLP spray guns without training: 49%
HVLP spray guns with training2: 61 %
Assume a facility uses 420 gallons/year of coatings (primer, basecoats, and clearcoats) to spray approximately
15 cars per week using conventional spray guns (40% transfer efficiency).
If the facility switches to HVLP spray guns without training workers on effective spray techniques (improves
transfer efficiency from 40% to 49%), then 343 gallons of coatings are required to spray the same number
of vehicles [420 gallons x 40%/49% = 343 gallons]—a savings of 77 gallons/year and $6,900.3
If the facility then decides to train workers on the proper use of HVLP spray guns (61 % efficiency), then 275
gallons of coatings are required [343 gallons x 49%/61% = 275 gallons]—an additional savings of 68
gallons/year and $6,100.3
The total annual savings realized by switching from conventional to HVLP spray guns (with training) would
be 145 gallons and $13,000.3
'Transfer efficiency estimates provided by the Spray Technique and Analysis Research (STAR) program at the Iowa Waste Reduction
Center.
2With training assumes the painter is using proper spray equipment, maintenance practices, and spray technique.
'Assuming an average coating cost of $90/gallon (1998 $s) (obtained through discussions with Philadelphia area auto refinishing
shops).
The mention or illustration of any product or company does not constitute an endorsement by the U.S. Environmental Protection
Agency.
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