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© 2010 All Rights Reserved. DeVilbiss Automotive Refinishing, a division of Inc.

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40 CFR Part 63 Subpart HHHHHH

National Emissions Standard for

Hazardous Air Pollutants: Paint Stripping

and Miscellaneous Surface Coatings

Operations

Presented by:

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Learning Objectives• List strategies to reduce MeCl usage • Identify spray area requirements• Identify ways to reduce coatings usage• Measure paint viscosity• Select spray equipment• Set up a spray gun• Balance a spray gun pattern• Show proper painting technique• Describe ways to increase transfer efficiencies• Clean and maintain a spray gun• Maintain a spray booth• List the steps for compliance

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Paint Stripping • 40 CFR Part 63 Subpart HHHHHH is intended to significantly

reduce the amount of hazardous air pollutants (HAP) introduced into the environment as a result of using strippers that contain MeCl (Methylene Chloride)

• It does this by requiring that facilities:– evaluate if the application requires stripping or if the part can be

dry sanded or recoated without the removal of paint– evaluate whether the paint stripping needs to be done using

stripper containing MeCl– optimize application conditions when using paint strippers

containing MeCl to reduce evaporation– practice proper storage and disposal of strippers containing

MeCl by storing in a closed, air tight container– maintain copies of annual usage of MeCl on site at all times with

proper MSDS sheets4

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Spray Area Requirements

• All sprayed coatings must be applied in a spray booth or prep station

• Spray areas large enough to hold a complete vehicle must have four complete sidewalls or curtains and a roof

• Parts and miscellaneous spraying must be done in a booth or prep station with a roof and at least 3 sidewalls or curtains

• The exhaust of the spray booth must be fitted with filters proven to be 98% efficient at capturing paint overspray

Example of negative pressure parts booth 5

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Eliminating Rework

• Measure coatings correctly• Maintain proper air line filtration• Maintain proper air line regulation• Use proper air hose and fittings• Perform scheduled booth filter

maintenance

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Measuring Viscosity• Viscosity is a continued resistance to flow• Paint companies supply specific mixing

information for their materials • Typically these measurements are shown as

a ratio of volume in their tech sheets. For example, they may be listed as 3 parts to 1 with 10% reduction or 3:1:10%

• To compensate for temperature changes and the differences in viscosity of specific toners, manufacturers will usually list a specific viscosity in their technical data sheets

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Measuring Viscosity• Commonly used viscosity measuring devices

– Zahn #2 - #3 cups are commonly used when measuring viscosity of US refinish materials

– DIN 4 cups are commonly used when measuring viscosity of European refinish materials

– They come in two different styles, “standard” or in a dip cup versions

– Standard cups are filled until the meniscus (concave upper surface of the liquid) disappears

– Dip cups are completely submerged– With a standard cup, measure the time from when the

fluid is released from the bottom of the orifice – With a dip cup, measure from then it is pulled out of

the liquid until the first break in the stream 8

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Measuring Viscosity –Step by Step

• Ensure that the cup is clean• Completely immerse viscosity

cup• Begin timing when the top of

the viscosity cup breaks the edge of the paint surface until the first major break in the fluid stream

• With some Din 4 dip cups the time must be doubled because they are half the size of a standard Din 4. Know what size cup you are using

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Compressed Air Filtration and Regulation

• Clean, dry, oil-free air is required when spraying either waterborne or solvent materials

• Even the slightest amount of contamination can cause coating imperfections

• Point of use filter / dryer / regulators provide the cleanest, driest air possible and therefore a superior finish

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Contaminants and Filters

• Water – centrifugal filter• Dirt, rust and pipe scale – centrifugal filter (5

micron filter)• Oil and oil vapor – coalescent filter (.01

micron filter)• Odor – charcoal filter (.003 PPM filter) • Humidity – desiccant filter (-40°F dew Point)• Air Control – regulator (>50cfm capacity)

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Centrifugal / Coalescent / Charcoal / Dual Regulation

• Used for painting in areas of low humidity, particularly with waterborne basecoats

• Utilizes an inlet shut off valve for maintenance

• Bowls are easily removed for maintenance

• Manual drains• Contains 2 self-relieving

high volume regulators for air to blower stand / spray gun Model # 130526

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Centrifugal / Coalescent / Desiccant Dryer

• For painting in areas of high humidity

• Filters remove water, dirt and oil down to .01 micron

• Desiccant removes humidity down to a dew point of -40 F

• Includes an inlet shut off valve for maintenance

• Bowls are easily removed for maintenance

• Desiccant in a bag makes changing simple

• Self relieving high volume regulator

Order# 13052213

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Laminar and Turbulent Air Flow

Laminar Air

Turbulent Air14

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Sources of Pressure Loss

Air Hose

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Air Hose Pressure Loss• Hose ID has the greatest effect on pressure loss • As length increases, pressure drop increases • A rough tube can cause up to a 50% increase in

pressure drop (i.e. poor quality or worn out)

15 CFM 25 CFM 15 CFM 25 CFM1/4" ID 35 psi 87 psi 50 psi *

5/16" ID 12.6 psi 31.5 psi 18 psi 45 psi3/8" ID 4.2 psi 10.5 psi 6 psi 15 psi

35' Hose 50' HosePressure Loss with 100 psi Inlet Pressure

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Proper Hose and Fitting Set Up

• Hose mounted directly to the regulator

• Hose ID of 3/8”• Hose length of 35’ or

as short as possible• Only one quick

disconnect at the gun• Digital gauge for

accuracy 18

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Select a Spray Gun

• Under EPA 40 CFR Part 63 subpart HHHHHH all coatings must be applied with an HVLP, electrostatic, airless, air assisted airless or a spray gun demonstrated to be equal in transfer efficiency to HVLP

• HVLP and air spray equipment demonstrated to deliver HVLP or better transfer efficiencies produce the highest quality automotive finishes

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Select a Spray Gun

• HVLP = (High Volume Low Pressure)– What does HVLP mean?

• Sprays at 10psi or less at the air cap at a given inlet pressure. The 10psi or less pressure is an internal pressure measurement taken at the center of the cap and at the air horn

– Identification • Gun must be marked with “HVLP” and the proper

inlet pressure that achieves 10psi at the air cap– Compliance paperwork for painter

• None

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Identification for HVLP

Marked on Gun Handle Marked on Air Cap

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Select a Spray Gun• Compliant Spray Gun

– What does compliant mean • Spray gun must deliver transfer efficiencies equal to or

better than HVLP at a given inlet pressure– Identification

• Spray gun must have the inlet pressure marked on it that achieves transfer efficiencies equal to or better than HVLP

– Compliance paperwork for painter• For spray guns that do not meet the designation of

HVLP, you must have documentation from the spray gun manufacturer that states that the gun has transfer efficiency equal to or better than HVLP

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Compliance Letter

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Correct Gun Setup(HA-5867) 35’ Air Hose / High Flow Fitting / ¼”(F)NPS

Digital Gauge

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Standardizing Gun Set Ups

• Improving work quality and productivity while controlling material usage involves developing procedures that produce high quality work consistently and efficiently

• A standardized set up is extremely important when setting up and balancing a spray gun in order to deliver optimal results in a quick repeatable manner

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Paint Company Information• DeVilbiss works with paint companies to update

spray gun charts with correct fluid tip and air cap selections

• These recommendations help maintain finish quality while minimizing material usage. Fluid tip recommendations control fluid flow through the gun. Air cap and inlet pressures ensure proper atomization of the specific materials being sprayed

• This information can be found in the technical data sheets for your paint manufacturers or can be found on the DeVilbiss website at www.autorefinishdevilbiss.com

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Gun Adjustments• Pattern Control Knob

– Controls the height of the pattern

– Balances the pattern• Fluid Adjustment Knob

– Controls the amount of fluid that comes out of the gun

• Air adjustment valve – Controls amount of air

entering the spray gun

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Initial Gun Set Up • The pattern adjustment knob should be adjusted

out as far as it will go or positioned where it will deliver the largest pattern possible

• Adjust the fluid control knob out until a full trigger pull can easily be achieved. Then adjust the fluid adjustment knob back in while holding a full trigger pull until the needle starts to put pressure on the trigger

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Digital Gauge• Determining the

correct inlet pressure is critical for atomization and color match

• Waterborne orientation coats are often sprayed at 12-14psi which can’t easily be measured with dial type gauges

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Split Pattern –Too Much Air Pressure

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How to adjust a split pattern• Perform a static and dynamic

spray pattern– A static pattern is a quick burst or

the peanut pattern shown on the left. This is to determine droplet size and evenness of pattern

– A dynamic pattern is a quick pass to see distribution on combined droplets

• Check to see if droplets at the edge of the pattern are suitable and even in size

• If so, adjust pattern control knob clockwise until pattern balances

• If droplets are too small, reduce air pressure until desired droplet size is achieved and then turn pattern in until it balances

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Narrow Pattern –Air Pressure Too Low

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How to adjust a narrow pattern

• Perform a static and dynamic spray pattern

• Adjust pattern knob all the way out

• Increase air pressure until pattern widens to an acceptable width and droplet size

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Balanced Pattern –Correct Air Pressure

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Correct Air Pressure, Balanced Pattern

• Perform a static and dynamic spray pattern

• Static pattern is evenly shaped with a consistent droplet sizing at the edge of the pattern

• Dynamic pattern delivers even material distribution throughout the sweep

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Keep Track of Gun Adjustments

• Once the gun has been correctly adjusted for air pressure, pattern size, and fluid flow, record the gun settings for that particular material

• Record air pressure• Count how many turns out the pattern control

knob is by adjusting it clockwise all the way in until it stops

• Count how many turns out the fluid control knob is by adjusting it clockwise all the way in until it stops

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Spray Gun SOPs

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Spray Distance

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Spray Distance

• Spray distance should be 5-8” away when spraying an automobile. Distances can be slightly greater when spraying fleet or some waterborne finishes

• Spraying closer than 5” tends to drive in-flight solvents into the finish causing hazing and solvent pop

• Spraying farther away than 8” tends to cause dry spray and orange peel

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Gun Targeting and Movement

• Wrist is flexible• Gun is held

perpendicular to the target

• Gun is moved parallel to the target

• Trigger is released at the end of each stroke

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Arcing• Wrist not flexible• Arcing motion• Uneven application of coatings• Varying gun distance leads to

uneven texture• Arcing at the end of each stroke

causes excessive overspray• Any time the spray direction deviates

from perpendicular to the target, transfer efficiencies and finish qualities diminish

• Arcing is a main cause of haloing along the blend line. As the spray gun arcs, the target distance increases which causes paint to reach the surface too dry. This causes mottling of metallics and creates texture that will show up differently under clearcoats 41

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• Tilting of the spray gun causes uneven film build

• This leads to striping and uneven texture

• In extreme cases, dry spray and sags can occur in the same panel

• Even slight tilting can increase the number of coats required to achieve hiding and deliver an acceptable finish

Tilting

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Proper Overlap

• 50% overlap is the minimum overlap possible to achieve uniform film thickness

• Because it is hard to be that robotic, typically overlap will need to be between 50 and 75% depending on how difficult the color is to spray

• 50% overlap would be spraying a pass across the target and then starting the top of the next pass in the middle of the pattern created by the first pass. 75% overlap would be to start the second pass ¼ down from the top of first pass

• Exceeding 75% leads to excessive film build 43

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Controlling Overspray

• Anytime the pressure is lowered or the pattern is turned in, material usage is typically reduced

• Primers that are going to be sanded can be sprayed at lower pressures with narrower patterns than topcoats to help reduce overspray

• Sealers can also be sprayed with less energy and narrower patterns to control paint usage

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Clean a Spray Gun• Guns should be thoroughly cleaned after

each use. Parts should be checked for wear and replaced as needed

• 40 CFR Part 63, Subpart HHHHHH states that all gun cleaning should be done in a closed gun washer or by cleaning the disassembled gun body by hand. This rule allows solvent to be flushed through the fluid passages of the gun without atomizing it

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Enclosed Gun Washers• Whether cleaning the gun by hand or using an enclosed

gun washer, the gun should be periodically broken down to ensure that no deposits of paint are left in the gun body

• A plug should be attached to the air inlet of the gun before it is placed in an enclosed gun washer

• After cleaning guns in an enclosed gun washer, guns should be removed, dried and lubricated

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Enclosed Gun Washers

• Some cleaning solutions can become corrosive over a period of time and alter the appearance and performance of the spray gun

• Separate waste streams are required for solvent and waterborne; therefore, separate gun washers for waterborne and solvent are required

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Cleaning by Hand• When cleaning by hand, disposable cup systems are

highly advantageous • Remove disposable cup and run solvent through the fluid

passages of the gun• Remove the air cap and brush with a soft cleaning brush.

Run small brushes through the annular hole in the air cap and wipe dry

• DeVilbiss Spray Gun Cleaning Kit (#192212) includes these brushes

• Do not mix solvent and water waste streams

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Maintenance

• Regularly lubricate the needle packing, air valve, adjusting screws, trigger stud, and air cap threads

Air Valve

Fluid Needle

Fluid Tip

Spreader Valve

Fluid Adjustment Screw

Air Cap

Needle Packing

Air Adjustment Valve

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Troubleshooting• The most common spray equipment problems

involve either the fluid tip or the air cap• Soak air caps in quality thinner or acetone.

Brush the front and back of the air cap with cleaning brushes and run brushes through the annular hole in the air cap

• Performing pattern checks on a regular basis is recommended

• Problems with uneven patterns can easily be diagnosed by simply rotating the air cap

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Troubleshooting

• Horn holes plugged• Obstruction on top or

bottom of fluid tip• Air cap or fluid tip seat

dirty

• Left or right side horn holes plugged

• Dirt on left or right side of fluid tip

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Troubleshooting • Pattern adjustment knob turned

in too far• Material flow exceeds the

capability of the cap• Atomization pressure too low• Material too thick

• Fluid adjustment knob set too far in• Atomization pressure too high • Pattern adjustment knob set too

far out for the material being sprayed

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Troubleshooting

• Loose or damaged fluid tip/seat

• Material too low• Obstruction in fluid

passage• Dry or loose needle

packing • Air vent in cup lid clogged

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Spray Booth Maintenance

• Clean the booth regularly and keep it clear of unnecessary items such as shelves and towel dispensers that can collect dust

• Clean walls and light covers regularly. Paint the booth walls as needed for high visibility

• Do not perform prep work in a spray booth• Door seals should be checked periodically to make sure they

are sealing• Waterborne dryer heads should be covered when not in use

to keep them clean• Intake filters should be changed according to booth

manufacturer’s specifications54

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Spray Booth Maintenance

• Final filters should be 10 micron or less– Anything larger than 10 micron will show up in a paint job

• Paint arrestor filters are required to be 98% efficient by EPA 40 CFR Part 63, Subpart HHHHHH. Filter manufacturer specifications have to be kept on file to meet this requirement

• If you have a booth maintenance contract, make sure that the filters match your filter specification to remain in compliance

• In order to deliver high throughput and get clean jobs, it is important to establish a filter change-out schedule

• Readings from a manometer or water column pressure gauge should be used to establish filter change frequency

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R U L E 4 0 T R A I N I N G

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© 2010 All rights reserved.A-2982 Litho in USA. 04/10

www.autorefinishdevilbiss.com800.445.3988

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