ahead of the pace newsletter-summer 2003 · 2018-06-13 · checked with a velometer. measurements...

INTHIS

ISSU

E:Pollution Prevention forPainting and CoatingCompliance Enhancement isa cooperative effort of theDesign for the Environment(U.S. EnvironmentalProtection Agency) and theIowa Waste Reduction Centerat the University of NorthernIowa.

Energy Consumption of Painting and Coating Can Be Reduced

A recent study by an IWRC specialist found that painting and coating equipment operators cansave money and reduce the amount of energy their operations consume by installing AC motor

controls.

Metal Finishing: case study 1

On-Site Reviews are a valuable service provided by the IWRC. One Iowa business has seen thesignificant impact this service has had on its facility’s finishing process through improved paint

usage, finish quality, emissions and booth maintenance.

News BriefsWith special seminars like Tech Days and PACE Process Training, the IWRC is able to assist

many small businesses like Ottumwa Works.

Wood Finishing: case study 2

Through On-Site visits, the IWRC helps businesses run at a top-notch rate. One Iowa facilitywas able to decrease its total material usage by 22 percent after implementing suggestions

made by the IWRC.

BETA: The Blueprint for EnvironmentalTechnical Assistance

BETA was developed to provide a readily available resource to assist new programs and newemployees with on-site assessment training. BETA provides them with information about the

business/industrial processes they will be reviewing.

Removing Waste and Improving Finish Qualityin the Auto Body Shop

With the high cost of conducting automotive paint systems being higher than ever, waste of anykind takes an expensive toll. Anything from keeping your facility clean to using the right techniques

and equipment can help save your business money. ...13... 12.....9..... 7.....3..... 1

by Jeff EnglandIWRC Environmental [email protected]

Ahead of the PAC2E1 Ahead of the PAC2E 2

iIn a recent study conducted bythe Iowa Waste Reduction Center(IWRC), Quality AssuranceManager Jeff England found thatmany painting and coating equip-ment operators can significantlyreduce not only the amount ofenergy their operations consume,but can realize monetary savingsby installing AC motor controlsinto their systems. In theMidwest, where colder climatesoften create higher energy prices,implementing AC motor speedcontrols in either a paint booth, a5-stage Pretreatment System or aPowder Coating Booth can provebeneficial to not only the envi-ronment, but a business’ pocket-book as well.

In the study, AC motor controlswere installed on three commonpieces of painting and coatingequipment in order to measurethe potential energy savings thatresulted. Energy savings are fromthe reduced electrical demand ofthe motor speed controllers com-bined with the resulting decreasein heating costs related to ventila-tion. Results were as follows:

v When installed in the paintbooth ventilation system,

which consisted of a 5-hpintake motor and a 15-hpexhaust motor, fan speed wasreduced by 23 percent with-out allowing ventilation to fallbelow the recommendedminimum. The cost ofinstalling the speed controlscame to $5,025; while inoperating costs, results fromthe reduction were $4,844 peryear for a booth operatingcontinuously. The financialpayback period for the ACmotor speed controls in thistype of system was about oneyear.

v The installation of motor con-trols into the 5-StagePretreatment System consist-ed of two 5-hp exhaust fanmotors. Installation cost wasonly $1,980 while a 7.5 per-cent fan speed reductionresulted in an annual savingsof $3,984 for a system oper-ating continually. The reduc-tion in this case is due to thecombined effects of reducedfan motor speed and reducedventilation. A system operat-ing 40 hours a week wouldsave an average of $940 peryear.

v Finally, AC motor speed con-trol was installed in a powdercoating booth ventilation sys-tem that consisted of two 3-hp motors, operating off of asingle speed controller. Thecost of installing the speedcontrollers on the powder-coating booth was $1,175.Due to the lower operatingcost of the powder-coatingbooth, it was expected tobenefit the least of threeequipment operations fromthe modification. Fan speedwas reduced by 33 percentwithout significantly reducingventilation, resulting in a sav-ings of $525 per year for abooth operating continuous-ly.

By incorporating AC motorspeed controls into painting andcoating operations, businesses,especially those that operateequipment in multiple shifts, canlower their energy use in a suffi-cient payback period. For moreinformation on installing speedcontrols into your operations, orfor a complete copy of the proj-ect report, call Jeff England ofthe IWRC at 800-422-3109 orvisit www.iwrc.org

BackgroundIn the spring of 2003, ProcessTraining staff visited a manu-facturing facility that finishedagricultural products. Thefacility’s coating supplier coor-dinated the site visit after real-izing that a number of applica-tion problems existed at thefacility. An equipment vendorfamiliar with the facility’s fin-ishing process and equipment(Spray Equipment and ServiceCenter Inc. [SESC]) alsoattended the site visit. SESChad visited the facility in thepast and had made a numberof recommendations towardimproving the facility’s applica-tion process. However, thefacility was hesitant on imple-menting those modifications.

The facility applies a fast-dry,general-purpose enamel. Thecoating was 30 percent solids(by volume) and the recom-mended dry film thickness forthe coating was 1.0 to 1.5 mils.The viscosity of the coating,out of the drum, was report-edly 28 to 32 seconds on aZahn #2 cup.

The facility experienced anumber of problems associat-ed with its finishing process.Dry film build measurementstaken on a number of finishedproducts indicated operatorswere applying excessive filmbuilds - anywhere from four tosix mils dry. This resulted inexcessive overspray, coatingusage and emissions. It alsocaused poor coating appear-ance (runs/sags) and perform-ance (cracking).

The facility operates an elec-trostatic air-assisted airlessspray gun fed from a 30:1pump. Paint applied to thesubstrate first passed throughan in-line heater for viscositycontrol and reduction. Thecoating was heated to a tem-perature of 136 degreesFahrenheit (at the in-lineheater) before it was circulatedout to the spray gun’s whiphose. The heated material wasthen re-circulated back to thedrum. Although the deliverysystem was equipped with aback-pressure regulator, nofluid regulator was plumbedinto the system (a fluid regula-

tor is a self-adjusting valve thatsenses fluid pressure at its out-let and keeps it constant). As aresult, the gun’s spray patternexperienced surging (and“tails”) when the pump cycled.Because of the surging duringpump cycles, the air regulatorfor pump operation was main-

tained at an elevated level –approximately 80 psi. Thisproduced an excessive fluidpressure of approximately2400 psi to the spray gun butavoided the surging problemexperienced at lower operatingpressures.

The electrostatic efficiency ofthe system was reviewed byobserving the degree of wrapon a piece of tubular steel andby checking continuity toground with a megohm meter.By observing the degree ofwrap achieved on the tubularsteel, it became apparent thatparts attached to the ground-

ing cable had no wrap whileparts hung on the conveyorrealized excellent wrap.Follow-up with megohmmeter measurements verifiedthat the grounding cableexceeded one megohm ofresistance to ground while theconveyor had good continuityto ground.

“ “


by Brian GedlinskeIWRC Environmental [email protected]

Ed ChestnutSpray Equipment and Service Center Inc.515-710-1661

Equipment modifications, sometraining and equipment maintenance

on the facility’s

paint usage, finish quality, emissionsand booth maintenance.

will undoubtedly result in a

significantimpact


The existing fluid filtrationsystem consisted of a 100-mesh screen in the pump man-ifold filter and a 100-mesh fil-ter in the spray gun’s fluid inlet.Although a 0.009-inch diame-ter fluid tip orifice was capableof providing the output need-ed for production, the facilityused an 0.011-inch fluid tiporifice because of frequent tipplugging.

The booth’s airflow was alsochecked with a velometer.Measurements indicated air-flow through the booth was, atbest, an average of 50 feet perminute. A review of the boothexhaust revealed loose fanbelts. An ensuing discussionwith facility staff also indicatedan overspray buildup inside thestack and on the exhaust fancould be contributing to thepoor airflow. A cursory inspec-tion of the downdraft spraybooth found air gaps in thebooth arrestor filters (because

of their placement/ orienta-tion). As a result, overspraycould bypass the filter mediaand enter the stack.

Modifications andBenefitsTo address the identified appli-cation problems, the followingchanges were implemented:

v For fluid pressure stabilityand control, a fluid regulatorwas installed at the pumpoutlet downstream of themanifold filter. Althoughfluid pressure at the regula-tor inlet fluctuates (frompump changeover), the reg-ulator maintains a set outletpressure to the spray gun,providing consistent materi-al delivery. As a result of itsinstallation, along with theinstallation of a more sensi-tive back-pressure fluid reg-ulator, the fluid pressure tothe spray gun was lowered

from approximately 2,400psi to 800 psi.

v The return line of the paintcirculation system wasplumbed back into thepump foot valve rather thatthe paint drum. This simpleplumbing fix circulatedheated material back to thepump intake, avoidingunnecessary solvent lossfrom the drum. The coatingdrawn into the pump intakewas also brought up tooperating temperature moreefficiently.

v To address frequent tipplugging with the 0.009-inchtip, a 200-mesh screen wasinstalled at the manifold fil-ter. A 100-mesh in-line filterwas also installed at thewhip hose. This improvedfluid filtration allowed the0.009-inch tip to be used forfinishing, resulting inreduced material consump-tion, improved atomizationand better electrostatic per-formance. At a given fluidpressure (for a light to medi-um viscosity fluid) an orificediameter decrease from0.011-inch to 0.009-inchrepresents approximately a30 percent decrease in fluiddelivery rate. Additionally,the decrease in operatingfluid pressure (i.e., 2,400 psito 800 psi) results in an evengreater decrease in fluid out-put.

v Alternative fluid tips (mach-ined with varying includedangles to produce different

size spray patterns) wereprovided to the operatorsalong with a brief review onfluid tip selection (i.e., ori-fice diameters and spray pat-tern size relative to the tipnumbering scheme).Because the facility finishedproducts that varied fromflat panels to products man-ufactured with small diame-ter tubular steel, a variety of0.009-inch diameter orificetips were provided to “bet-ter fit” the various partgeometries finished at thefacility. The intent was toselect a fluid tip with a spraypattern appropriately sizedfor the parts finished,improving transfer efficien-cy.

v The air control valve on theair-assisted airless spray gunwas being used wide open.To minimize fluid dropletvelocity and optimize elec-

trostatic benefit, operatorswere instructed on air-assist-ed airless spray gun setup.Operators were shown howto set the air control valvejust to the point where“tails” were removed fromthe spray pattern. The air tothe spray gun was also limit-ed to the air pressure settingrecommended by the spraygun manufacturer.

v To improve booth airflow,belts for the exhaust fanwere tightened, the exhauststack and fan blades werecleaned of overspray andbooth filters were better fit-ted to eliminate any air gapsthat would allow oversprayto bypass the filter media.Improving booth airflow inconjunction with loweringthe spray gun operatingpressures (air and fluid)should also have a positiveimpact in regard to the

amount of overspray onbooth walls and the workfloor.

ConclusionBecause the facility is currentlyfine-tuning its coating formu-lation (in an effort to maintainthe fast-dry characteristicsneeded throughout the year),no fair “before-and-after”number comparison in regardto material consumption canbe made at this time. However,the $1,100 investment inequipment modifications,some training and equipmentmaintenance will undoubtedlyresult in a significant impact onthe facility’s paint usage, finishquality, emissions and boothmaintenance. Addition-ally, spray operators are moreknowledgeable of the finishingequipment, have much greatercontrol of the process andbenefit from a healthier, saferwork environment.

Properly selected fluid filters remove particulates that would otherwise lead to frequent tip plugging in airless and air-assisted airless application systems.

““[After training] spray operators are more

knowledgeableof the finishing equipment, have much

of the process and benefit from ahealthier, safer work environment.

greater control


Tech Days Event:September 23-25A Tech Days event, featuring coating equipment manufac-tured by Graco Inc. and Parker Ionics, will be held onSeptember 23, 24 and 25 at the IWRC’s Painting & CoatingProcess Training facility. The three-day event is an opportu-nity for businesses to visit with industry experts, attend tech-nical presentations and review the latest application equip-ment offered by Graco and Parker Ionics. This event is sureto provide technical information beneficial to your liquid orpowder coating finishing process. For more details, pleasecontact Brian Gedlinske or John Whiting of the IWRC at800-422-3109, [email protected] or [email protected]

Ottumwa Works:Improving CoatingPerformanceJohn Deere Ottumwa Works recently utilized the trainingfacility’s resources to evaluate coating performance using afive-stage pretreatment system. Ottumwa Works currentlyuses a two-stage spray washer to prepare parts for painting,but will soon upgrade to a five-stage system. By improvingcoating performance through superior pretreatment andsome coating reformulation, Ottumwa Works hopes to moveto a single coat application for its ground-engaging parts anda two-step finishing process (an enamel dip followed by anair spray application of a two-component enamel) for itsclass A and B pieces. Ultimately, this process change is antic-ipated to reduce the facility’s VOC and HAP emissions by 25to 30 percent.

Hands-onSpray GunSetup andOperationEach month the IWRC’sProcess Training program offersa free 2 1/2-day, “hands-on”training course covering a vari-ety of painting and coatingprocesses. The program wasdeveloped to educate regulatorypersonnel, technical assistanceproviders and businesses oncoating processes in an effort toimprove efficiency, reduce wasteand decrease air emissions. Asindicated in the course agenda,topics addressed range frompretreatment to liquid applica-tion to powder coating. Forconvenience, businesses are wel-come to send representatives topertinent portions of the train-ing program. Additionally, toease the financial burden associ-ated with attending the pro-gram, regulatory personnel,technical assistance providersand end users are eligible fortravel expense reimbursement.If interested in attending, pleasecontact Brian Gedlinske([email protected]) or JohnWhiting ([email protected]) fortraining dates.

PAC2E Process TrainingPPaaiinnttiinngg aanndd CCooaattiinngg PPrroocceessss TTrraaiinniinngg PPrrooggrraammTTrraaiinniinngg AAggeennddaa

7:45-8:00 INTRODUCTION 4 Tour of facility

8:00-12:00 PRETREATMENT 4 Cleaning, Phosphatizing and Process Control4 Equipment Review

12:00-1:00 LUNCH

1:00-3:00 INTRO TO APPLICATION EQUIPMENT AND APPLICATION EFFICIENCY4 Air Spray, Hydraulic Atomization, Powder Coating4 Viscosity, Atomization and Finish Quality4 Transfer and Film Build Efficiency4 Spray Technique4 Recognizing Problem Areas and Improving Efficiency

3:00-5:00 INTRODUCTION TO COATINGS 4 Coating Materials – Liquid and Powder4 Components, Properties and Application4 Process Control/Troubleshooting

8:00-11:00 INTRO TO APPLICATION ENHANCEMENT EQUIPMENT, GROUNDING AND POWDER COATING4 Electrostatics4 Grounding4 Hangers and Part Presentation4 Powder Coating Equipment - Hands-on

11:00-12:30 LUNCH

12:30-5:00 LIQUID SPRAY APPLICATION EQUIPMENT ANDCONCEPTS

4 Air Spray Equipment - HVLP and Conventional 4 Equipment Setup4 Hands-on Spray Gun Setup and Operation

8:00-11:00 LIQUID SPRAY APPLICATION EQUIPMENT – AIRLESS AND AIR-ASSISTED AIRLESS4 Safety4 Tip Selection, Fluid Pressure and Air Pressure

DAY1

DAY2

DAY3


BackgroundIn the fall of 2002, ProcessTraining staff partnered withESCOM on a site visit to awood finishing facility. Thefacility had encountered someregulatory issues and was look-ing for ways to cut productioncosts and emissions. The focusof the site visit was the stainingline and the facility’s

sealer/topcoat applicationprocess. These coating

operations accounted forthe bulk of the facility’s

material usage andemissions.

The staining lineused pressure fedHVLP sprayguns to apply asolvent-based,wipe-able stainto the substrate.The spray gunswere fitted with0.055-inch fluidnozzle/needleair cap combina-

tions. During acursory review of

the stainingprocess, it was deter-

mined that the atom-izing air to the HVLP

spray guns was unregulat-ed and well above any inlet

pressure that would keep theprocess HVLP compliant.Further inspection of thestaining process revealed inop-erable fluid regulators, resultingin excessive and uncontrolledfluid output from the sprayguns (other than what little

could be accomplished by clos-ing off the fluid needle adjust-ment valve).

Air-assisted airless spray gunswere used to apply a sealer andhigh-gloss lacquer topcoat. Theviscosity of the sealer and top-coat materials was reported atapproximately 25 seconds on a#2 Zahn cup. Air-assisted air-less spray guns were fitted with0.021-inch diameter fluid tips.The included angles machinedinto the tips were designed toproduce 12- to 14-inch spraypatterns at a 12-inch gun-to-target distance. Coatings werefed to the spray guns using 30:1pumps. Fluid pressures to thespray guns averaged around1,900 psi although they variedanywhere from 1,550 to 2,200psi. Air pressure to the sprayguns varied from 30 to 68 psi atthe wall regulator.

by Brian Gedlinske

IWRC Environmental [email protected]

Mary Jean Gates PE, REM - Environmental Services

Company (ESCOM) [email protected]

““It was readily apparentthat the

applica-tionprocesswas being operated moreas an

airlesssystem.


by Chris Horan IWRC Environmental [email protected]

Based on the viscosity of thecoatings sprayed and the fluidpressures used, it was readilyapparent that the applicationprocess was being operatedmore as an airless system thanan air-assisted airless system.This was demonstrated byturning off the air supply tothe gun and still achieving auniform spray pattern.

Modifications andBenefitsTo address the identified appli-cation problems, the followingchanges were implemented:

v Air regulators were installedto control the atomizing airto the HVLP spray guns.Instead of operating at linepressure, the atomizing airto the spray guns could nowbe controlled and the stain-ing process could become“HVLP compliant.”Addition-ally, with more deliberatedetail to spray gun setup andoperation, the stainingprocess could be completedwith a much “softer” spray,resulting in reduced over-spray, material usage andemissions.

v Fluid pressure regulatorswere replaced or repaired toprovide control over fluiddelivery from the HVLPspray guns. Prior to theirrepair/replacement, HVLPspray guns delivered a highvelocity fluid stream fromthe nozzle, making it diffi-cult (at best) for operators toapply the stain efficiently.Control over spray gun fluid

pressure equates toimproved operator control,reduced atomizing air pres-sures and a more efficientapplication process.

v Air and fluid pressures tothe air-assisted airless sprayguns (used to apply sealerand topcoat) were reduced.This produced a much“softer” spray by reducingair turbulence. In turn, thisreduced overspray created amore favorable work envi-ronment for the operator.The air pressure to the spraygun was reduced to a settingthat eliminated "tails" fromthe spray pattern and pro-vided adequate atomizationin regard to finish quality.The reduction in fluid pres-sure also gave operatorsmore control over the spray

gun (resulting in fewerruns/sags) while still allow-ing them to keep up withproduction. It also meantless tip wear.

v The fluid tips were replacedwith 0.017-inch tips thatproduced an 8- to 10-inch ora 10- to 12-inch spray pat-tern at a gun-to-target dis-tance of 12 inches. Thesenew tips kept more of thespray pattern on the productbeing finished while reduc-ing material output andimproving atomization. At agiven fluid pressure (for alight to medium viscosityfluid) an orifice diameterdecrease from 0.021-inch to0.017-inch represents over a37 percent decrease in fluiddelivery rate.

ResultsMonitoring data indicates thefacility realized a double-digitpercentage decrease in coat-ings usage as a result ofchanges implemented duringthe site visit. Over the samethree-month period before andafter the site visit, the amountof sealer and high-gloss lac-quer sprayed by the facilitydropped by approximately 24and 32 percent, respectively.This decrease in material con-sumption was normalized forthe same amount of produc-tion. Overall, a 22 percentdecrease in total material usagewas realized for the facility, anumber equivalent to over$100,000 in material costs and33 tons of VOC emissions peryear.

““A22percentdecreasein total materialusage was realized forthe facility.

The Iowa Waste ReductionCenter’s (IWRC) SmallBusiness Compliance Alliance(SBCA) recently developed atraining program for otherenvironmental assistanceproviders, as well as packagedthe corresponding materialsin a manual. The need for TheBlueprint for EnvironmentalTechnical Assistance (BETA)was based on the lack ofexisting training for environ-mental technical assistanceproviders. New programs andnew employees do not have areadily available source foron-site assessment training,nor a way to learn about thebusiness/industrial processesthey will be reviewing.

BETA is comprised of acompliance assistance andpollution prevention on-sitereview training guide thatincludes checklists, regulatorysummaries, vendor informa-tion, a client entry databaseand example on-site reportsfrom a variety of businesssectors. The training guide, inconjunction with on-site busi-ness visits, has formed thebasis for training technicalassistance providers from twoother states. A typical BETAvisit includes two on-site

reviews with IWRC staff, areview of regulatory sum-maries, training with the clienttracking database and trainingon how to access vendorinformation. The training iscustomized when the traineehas particular projects as theirfocus and site visits arearranged with IWRC staffwith that applicable expertise.

The IWRC has developedseveral different modules ofan overall environmentalmodel. This allows existingprograms to implement onlythose modules they do notalready have in place, or findmost useful for the needs oftheir state. The modulesdeveloped include:on-site technical assistancetraining, client tracking data-base, workshops, small busi-ness assistance providers’roundtable, website templatewith regulatory and wastetype summaries.

If your organization is inter-ested in additional informa-tion about the BETA trainingprogram please contact ChrisHoran or Jeff Beneke of theIWRC at 800-422-3109 orvisit www.iwrc.org.


Approximately $70 of that isthe body shop’s cost for all liq-uid paint products required. Ifmost repairs were over-mixedby 25 percent (10 percent over-mix is appropriate) the shopwould spend an unnecessary$10 for every car painted orabout $5,000 each year in atypical shop. The potential sav-ings more than merit a man-aged approach to reducing liq-uid paint waste.

Most auto paint companiesoffer a computer driven mixingscale that will calculate colorformulation and catalyzationratios down to a fraction of agram. By employing this built-in technology, smaller quanti-ties are very easily mixed. Totake full advantage of thesesmart mixing scales, the paintershould mix every liquid com-ponent on the computer scale.Exact ready-to-spray ounces ofprimer surfacer, sealer, base

color and high solids clear coatcan complete a smaller repairwith “exactly” the rightamount of catalyzed andreduced material. Once cat-alyzed, auto paint pot life ismeasured in hours at best. Tohelp manage their financial

investment, savvy painters canalso tie each mix to the correctcustomer repair order throughthe computer, tracking costs byeach job.

A simpler and very effectivemethod to track over-mixing

by Mark ClarkProfessional PBE [email protected]

““ Each typical auto painteruses about

$2,000 worth of liquid eachmonth.Waste of any kindtakes an expensive

toll.

tToday’s automotive paint sys-tems cost more than everbefore. Not surprisingly, greattechnology costs money. Notonly are today’s paints compli-ant with the National Rule onsolvent content (VOC), theyare also much more durable. Atmore than $100 dollars per gal-lon, these technically impres-sive coatings require carefulstewardship, not only for emis-sion control but cost controltoo.

Typically, the body shopspends about 70 cents of everydollar in refinish material onliquid paint. Undercoats, seal-ers, color systems, clear coats,solvents and catalysts aremixed together in exact pro-portions to yield amazinglydurable auto finishes. Eachtypical auto painter uses about$2,000 worth of liquid eachmonth. Waste of any kindtakes an expensive toll.

Preventing reworkI contend that the main causeof wasted materials is poor ini-tial repair. When work must bere-repaired the solvent emis-sions and the monetary costboth double. The shop isallowed a material allowancefrom the insurance companyresponsible for repair. Morethan 90 percent of all collisionrepairs are paid by insurance(this is based on a multiple ofthe estimated labor hours ofpaint time and a specific hourlyallowance rate, typically $20-$26 per labor hour). However,they only pay for one correctpaint repair. The body shop isout the cost of all new materi-als and lost profit on the origi-nal repair. Prevent re-work tomake the greatest improve-ment in your paint waste.

Common causes for a paint re-do include a poor color matchand excessive dirt and contam-

ination in the finish. Prudentauto painters use sample sprayout panels and clever blendingtechniques to effect an invisi-ble paint repair. Less cleverpainters re-spray the entiremulti-panel repair when a colormismatch is finally discovered.Prudent painters employ cleanpaint suits, careful prep andmasking and a well maintainedspray booth. Less skillfulpainters spend hours andhours perfecting the finalproduct to flaw-free originalequipment standards by hand,sanding and power buffingendlessly.

Material Waste andMixingNext on the list of materialwaste pitfalls is over-mixing.Not only does the excess paintproduct cost lots of money, itbecomes expensive hazardouswaste as well. A typical autobody repair is $1,500 in total.


by auto body painters is toemploy intermediate haz-ardous material containers forindividual painters. Rather thanhave every painter dumpexcess paint liquids into a com-mon 55-gallon drum of haz-ardous waste like most shopsdo, have the painters pour theirwaste into one or five-galloncans first. In a controlled timeperiod, each painter wouldhave his or her waste measuredand recorded before beingpooled into the shop’s mainwaste drum. Painters could becompared against past per-formance or individual wastegenerated per paint labor hour.In either case, over-mixingabusers are quickly identified.Rather than punishing thewasteful painters, rewardingthe frugal ones makes moresense to encourage everyone’scompliance.

HVLP and theEnvironmentIt is beneficial to the local airquality to minimize the

Hazardous Air Pollutants(HAPS) and Volatile OrganicCompounds (VOCs) emittedwhile spray-painting collisionrepairs. Employing spray gunswith high transfer efficiencymakes economic and environ-mental sense everywhere and ismandatory in many regulatedareas around the country. Highvolume, low pressure, gravityfeed, air atomized spray gunsare the norm across the UnitedStates. These HVLP sprayguns theoretically enable trans-fer efficiency of around 65percent. The combination oflow atomization pressures (lessthan 10 PSI at the air cap) andlarger paint droplet size makethis type of gun much moreefficient than the former autobody industry standard spraygun. From the 1920s until theSouth Coast Air QualityManagement District(SCAQMD) passed Rule 1151in 1987, most auto body sprayguns were siphon feed, bottomcup spray guns. With large

fluid openings and powerfulventuri action at the air cap,these guns blew and swirledtheir contents into large cloudsof finely atomized paint mist,often having transfer efficiencyonly in the 30 percent range.

The switch to higher transferefficiency spray guns has beengood for both the painter’shealth and the local air quality.A recent development by sev-eral paint gun manufacturersmay signal the next step in autorefinish spray equipment. Thecontent of Rule 1151, whichmany other regulations aremodeled after, is targeted at allspray equipment that is 65 per-cent transfer efficient, not justHVLP equipment. It is possi-ble to get 65 percent transferefficiency from both electro-static and airless spray.However, it is very difficult toachieve the faultless Class ‘A’finish required to matchtoday’s autos with eithermethod. New gravity feed,high transfer (but not HVLP)spray guns have recently beengiven SCAQMD approval.

While operator training is thebest transfer efficiency deter-miner, the current generationof guns will still enjoy poten-tially high transfer efficiency.They will also allow the painterto raise the air pressure at theair cap past the current 10-PSImaximum. This is good newsfor painters in heavily regulat-ed areas who must get thesame stunning Class ‘A’ finishusing extra low VOC products.Auto painters in Los Angelesmust atomize clear coats that

are as low as 1.9 pounds ofVOC per gallon. These super-high-solids resins benefit great-ly from higher atomizationpressures. While looking likeclose cousins of today’s HVLPguns, these newly approvedguns open another importantavenue to enable the paintersto work their magic.

And magic it is. Consider thatin a largely uncontrolled envi-ronment, using air dry, site-mixed urethane resins, the localauto body shop can offer apaint repair both as attractiveand as durable as the factoryapplied finish. Original equip-ment manufacturers spendmillions of dollars to create themost perfect, repeatable,healthy, clean and compliantspray system possible. Localauto body painters use sometop-notch chemistry and a fewpreventative steps along withlots of post-paint cleanup anddetailing.

Take Time to Save TimeCleaner vehicles, painters andspray booths quickly affect ini-tial paint finish quality; truly astitch in time saves nine. Anytime the painter spends keep-ing the process clean andorderly is saved many timesover upon completion. Slowersolvents, heated exhaust air-flow and good spray techniquemake the finish as smooth andglossy as humanly possible.However, it is very difficult tokeep the refinish repair as cleanas the OEM version. As aresult almost every paint jobcoming from a body shoptoday will have some hand lev-

eling, polishing and buffingperformed before delivery.

Since many auto painters con-tinue to employ solvents thatevaporate too fast, their paintwork often has orange peel.Orange peel is always causedwhen the droplets of paintdon’t melt completely into oneanother (Slowly evaporatingsolvents stay inside the paintfilm long enough to flow outsmoothly). To remove this hi-lo texture from the final clearcoat, painters wet sand withvery fine grits of sandpaperfirst. Grits as fine as 1500,

2000, 2500 or even 3000 ANSIare used to level the paintedfinish flat. Small particles of

dust or other airborne clutterare removed using a rigid sand-ing block of some kind to pre-vent undercutting the contami-nated areas. Finally, the gloss isrestored and enhanced by pol-ishing with a suitable com-pound on a power buffer.

Typical paint detailing thesedays employs both wool andfoam rubber polishing pads. Ineither event, the polishershould turn relatively low RPM(1,500-2,000) to keep fromgenerating surface frictionheat. A lightly abrasive polish-ing compound brings back theshowroom perfect paint glossfrom the sanded clear coat. Itis possible to heat and re-flowfresh auto paints so completelyas to ruin them. Burned orburned through paint repairsmust be re-done and the cycleof material waste begins again.As always, the paint shop thathas written procedures foreach step in the repair processwill have higher quality repairswith fewer mistakes.

The outlook is bright for autopaint technology. New ultraviolet cured finishes are thenext technological resin jump.Newer, better spray guns areon the market today. The airquality has improved nationallydirectly from changes made byauto body shops since the 1987and 1990 legislation. We’redoin’ good man! A betterrepair with more compliantmaterials and low emissionspray equipment is a win for usall.

““Any time thepainter spendskeeping theprocess

cleanand

orderlyis savedmanytimes overupon completion.

PAC2EPainting & Coating Compliance Enhancement

Iowa Waste Reduction CenterUniversity of Northern Iowa1005 Technology ParkwayCedar Falls, IA 50613-6951www.iwrc.org

Return Service RequestedSum

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U.S. PostagePAIDUNI

ahead of the pace newsletter-summer 2003 · 2018-06-13 · checked with a velometer. measurements...

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