Manual Gun Cleaning Processes

Module 10-1 (a)

Manual Gun Cleaning ProcessesManual Gun Cleaning Processes

nManual equipment cleaning generates largequantity of wastes if not done properly.nManual equipment cleaning generates largequantity of wastes if not done properly.

nSolvent is exposed to the air and evaporatesnSolvent is exposed to the air and evaporates

–About 20% of total VOC’s (volatile organiccompounds) lost from auto refinishing happensin equipment cleaning operations.–About 20% of total VOC’s (volatile organiccompounds) lost from auto refinishing happensin equipment cleaning operations.

–Most cleaners are entirely of organic solvents.–Most cleaners are entirely of organic solvents.

Module 10-1 (b)

Manual Gun Cleaning ProcessesManual Gun Cleaning Processes

nGood cleaning is VERY importantnGood cleaning is VERY important

–Essential to achieving a quality finish.–Essential to achieving a quality finish.

–Needed for high transfer efficiency.–Needed for high transfer efficiency.

–Guns are machined to very close tolerances.–Guns are machined to very close tolerances.

–Dried paint and obstructions affect gunperformance.–Dried paint and obstructions affect gunperformance.

Module 10-1 (c)

Manual Gun Cleaning ProcessesManual Gun Cleaning Processes

nManual Cleaning Process Steps:nManual Cleaning Process Steps:

–All paint is removed from the cup.–All paint is removed from the cup.

–Air hose and cup is removed, the gun istriggered to remove paint from the siphon tube.–Air hose and cup is removed, the gun istriggered to remove paint from the siphon tube.

–Clean thinner is poured into the cup andreattached to the gun.–Clean thinner is poured into the cup andreattached to the gun.

–Air supply is reattached, the thinner is sprayedthrough the gun.–Air supply is reattached, the thinner is sprayedthrough the gun.

Module 10-1 (d)

Manual Gun Cleaning ProcessesManual Gun Cleaning Processes

–Operators finger is place over the fluid tipwhile spraying to backwash the gun.–Operators finger is place over the fluid tipwhile spraying to backwash the gun.

–Cup is removed and thinner poured out.–Cup is removed and thinner poured out.

–Gun is wiped down using a rag or paper towel.–Gun is wiped down using a rag or paper towel.

–Air cap is removed and cleaned with a cleaningbrush.–Air cap is removed and cleaned with a cleaningbrush.

–Cleaning brush is also used to clean otherexternal moving parts and behind the trigger.–Cleaning brush is also used to clean otherexternal moving parts and behind the trigger.

Module 10-1 (e)

Manual Gun Cleaning ProcessesManual Gun Cleaning Processes

–A metal object is used to clean the smallpassageways–A metal object is used to clean the smallpassageways

»resulting in damage and reduced gun efficiency»resulting in damage and reduced gun efficiency

–Gun is reassembled and returned to the storagearea.–Gun is reassembled and returned to the storagearea.

–Easy to see how 20% of VOC’s are generatedduring the manual cleaning process.–Easy to see how 20% of VOC’s are generatedduring the manual cleaning process.

Module 10-2 (a)

Mechanical Enclosed GunCleaning SystemMechanical Enclosed GunCleaning System

nMechanical Cleaning Process Steps:nMechanical Cleaning Process Steps:

–Remove all the remaining paint from the cup.–Remove all the remaining paint from the cup.

–Remove air hose and pull the trigger to removepaint from the siphon tube and/or fluid passagesinside the gun.–Remove air hose and pull the trigger to removepaint from the siphon tube and/or fluid passagesinside the gun.

–Rinse the cup with a small amount of thinner.–Rinse the cup with a small amount of thinner.

–Put a small amount of solvent in the cup,connect air line to pressure the cup.–Put a small amount of solvent in the cup,connect air line to pressure the cup.

Module 10-2 (b)

Mechanical Enclosed GunCleaning SystemMechanical Enclosed GunCleaning System

–Disconnect the air line from the gun, purge thegun, drain solvent into the hazardous wastestorage drum.–Disconnect the air line from the gun, purge thegun, drain solvent into the hazardous wastestorage drum.

–Place the disassembled gun (with all pressuregauges removed) in the gun washer.–Place the disassembled gun (with all pressuregauges removed) in the gun washer.

–For siphon or pressure cup-type guns, place thesiphon tube on the cleaning jet, the gun triggeris locked open using a locking plate.–For siphon or pressure cup-type guns, place thesiphon tube on the cleaning jet, the gun triggeris locked open using a locking plate.

Module 10-2 (c)

Mechanical Enclosed GunCleaning SystemMechanical Enclosed GunCleaning System

–For gravity-feed guns, the gun is placed upsidedown with the fluid orifice on the cleaning jet.–For gravity-feed guns, the gun is placed upsidedown with the fluid orifice on the cleaning jet.

–Close the lid and turn the washer on.–Close the lid and turn the washer on.

–Washer runs for manufacturer’s recommendedamount of time (often only 1 - 3 minutes.)Gun and parts are ready to be removed andused again.–Washer runs for manufacturer’s recommendedamount of time (often only 1 - 3 minutes.)Gun and parts are ready to be removed andused again.

–Shut the lid after using the gun washer toprevent solvent evaporation.–Shut the lid after using the gun washer toprevent solvent evaporation.

Module 10-2 (d)

Mechanical Enclosed GunCleaning SystemMechanical Enclosed GunCleaning System

nVOC emissions from enclosed gun washingsystems have yet to be accurately measured.nVOC emissions from enclosed gun washingsystems have yet to be accurately measured.

–Reductions are estimated to be substantial.–Reductions are estimated to be substantial.

nTo reduce air emissions further:nTo reduce air emissions further:

–Use cleaning solvents low in volatile organiccompounds (VOC’s).–Use cleaning solvents low in volatile organiccompounds (VOC’s).

–In high volume shops, two gun wash systemscan be used.–In high volume shops, two gun wash systemscan be used.

Module 10-2 (e)

Mechanical Enclosed GunCleaning SystemMechanical Enclosed GunCleaning System

»Use the first system for initial cleaning»Use the first system for initial cleaning

»The second for final cleaning.»The second for final cleaning.

»When the final cleaning solvent becomes too dirtyfor cleaning, switch it to use for pre-cleaning.»When the final cleaning solvent becomes too dirtyfor cleaning, switch it to use for pre-cleaning.

»When the pre-cleaning solvent becomes too dirty, itshould be recycled.»When the pre-cleaning solvent becomes too dirty, itshould be recycled.

nAdvantages of mechanical gun washsystems are:nAdvantages of mechanical gun washsystems are:

–Reduced employee exposure to hazardoussolvents–Reduced employee exposure to hazardoussolvents

Module 10-2 (f)

Mechanical Enclosed GunCleaning SystemMechanical Enclosed GunCleaning System

–A reduction in the amount of thinner necessaryfor cleaning by 50% or more–A reduction in the amount of thinner necessaryfor cleaning by 50% or more

–Save time spent gun cleaning by up to 60%over manual cleaning–Save time spent gun cleaning by up to 60%over manual cleaning

–Reduced VOC emissions–Reduced VOC emissions

Module 10-2 (g)

Mechanical Enclosed GunCleaning SystemMechanical Enclosed GunCleaning System

nWastes from Mechanical Cleaning SystemsnWastes from Mechanical Cleaning Systems

–Paint sludge will collect in the gun washer andrequires disposal.–Paint sludge will collect in the gun washer andrequires disposal.

»Sludge is hazardous and should be disposed by ahazardous waste management company.»Sludge is hazardous and should be disposed by ahazardous waste management company.

–Dirty cleaning solvent can be recycled eitheron-site or off-site and be reused.–Dirty cleaning solvent can be recycled eitheron-site or off-site and be reused.

Module 10-3 (a)

Improved Manual Gun CleaningImproved Manual Gun Cleaning

nSpray solvent through gun into an enclosedbackdrop or container to catch solvent forreuse or recycling.nSpray solvent through gun into an enclosedbackdrop or container to catch solvent forreuse or recycling.

–Store the solvent in a closed container to let thesolids settle to the bottom.–Store the solvent in a closed container to let thesolids settle to the bottom.

–Decant (pour off) the clear solvent and save itto use it again for cleaning.–Decant (pour off) the clear solvent and save itto use it again for cleaning.

Module 10-3 (b)

Improved Manual Gun CleaningImproved Manual Gun Cleaning

–Properly store and dispose the paint waste thatsettles to the bottom .–Properly store and dispose the paint waste thatsettles to the bottom .

nIf passageways are clogged, use a broomstraw or a soft wood toothpick to clearthem.nIf passageways are clogged, use a broomstraw or a soft wood toothpick to clearthem.

nDon’t use metal objects to clearpassageways.nDon’t use metal objects to clearpassageways.

–damages spray orifices & reduces efficiency.–damages spray orifices & reduces efficiency.