Paint and Coatings

Washington State Department of Ecology

Top Tips for Pollution Prevention in Painting and Coatings

Use dedicated equipment and lines to minimize clean-out between coating changes; reduce the number of coating changes through techniques like light-to-dark batch sequencing.
Pre-inspect parts for obvious defects, before painting.
Reclaim and reuse solvents onsite.
Flush first with dirty solvent, then fresh solvent.

Modify the spray booth to allow recovery and reuse of overspray solids.
Size the paint cup on spray guns appropriately.
Automate spray and dip operations when possible.
Isolate spray booths for solvent-based coatings from spray booths for water-based coatings.
Keep solvent soak tanks away from heat sources.
Use high volume low pressure (HVLP) spray apparatus to increase transfer efficiency.

Train employees to use only small amounts of solvents for cleaning.
Flush equipment first with dirty solvent before final cleaning with virgin solvent, or pre-clean items with rags before cleaning with solvents.
Use virgin solvents for final equipment cleaning, then reuse it as paint thinner.
Consolidate solvent cleaning operations and use a multipurpose solvent.
Reuse cleaning solvents for a resin system by allowing solids to settle out of solution.
Use pressurized air mixed with a mist of solvent to clean equipment.
Keep the wash-off tank covered when it is not in use.
Minimize dripping by tilting or rotating parts to drain as much solvent as possible and by allowing sufficient dry time.
Use rags rather than disposable wipes whenever possible. Launder the rags in-house or locate a commercial laundry in the area that can provide the service.
If disposable wipes are used, remove as much solvent from them as possible before disposing of them. Keep the used wipes and the spent solvent in separate containers.
Use low-volume water cleaning systems.
If possible, return coatings with expired shelf life to the manufacturer, sell them, or use them as primer.

Where possible, use coatings that minimize VOC emissions, such as water-borne, powder coatings, UV-cured, etc.
Use good inventory management methods to reduce waste: rotate stock to avoid out-dated paints; avoid ordering excess amounts; minimize vendor samples that must be discarded; minimize container waste.
Where possible, use heat-thinning rather than thinning with solvents.

Operator training and experience have been shown to be the biggest factor affecting P2.
Use the most efficient gun for the specific job (HVLP, electrostatic, etc.).

Minimize use of stripper.
Use spent stripper as a rough pre-stripper on the next item.
Consider the use of the following methods of stripping paint: dry ice pellets, abrasive media, plastic media bead-blasting, cryogenic, thermal, wheat starch media, and laser or flash lamp.

Train spray gun operators in proper spray techniques to minimize generation of waste coating.
Pre-inspect parts to ensure it is dry, clean and dust-free, and to prevent painting of obvious rejects.
Schedule coatings to minimize color changes, or paint with lighter colors before darker colors to minimize the need for equipment cleanouts.
Mix only as much coating as is needed for a job. Train employees to estimate amounts and mix paints correctly.
Save off-color paint for other jobs.
Apply extra coats to use excess paint.
Avoid the need for re-coating by first inspecting the area to be painted.

Use powder coatings to eliminate VOC emissions and obtain high transfer efficiency.
Use water-based coating to reduce solvent emissions.