Substitution: Using Safer Products
Paints, primers, reducers, wiping solvents, caulks and adhesives can be hazardous to your health. The risk can be greatly reduced through good ventilation, good work habits and engineering controls, but more effectively by substitution - using a product that is less likely to do harm. There may still be some risk with the replacement material, but safer materials for many tasks are available. Read the labels and MSDSs!
You don't have to compromise the quality of the repair by using these less toxic materials. You can still maintain high standards and limit your employees' exposure to hazardous materials. Substitution is an effective means of creating a cleaner workplace. Work with your suppliers to select safer products. Here are some suggestions:
Solvent Wiping / Car Cleaners
Solvent-based cleaners evaporate quickly, releasing toxic vapors into the air. Traditional car washes, good old soap and water, can be used to clean a vehicle prior to a solvent wipe. If the car is clean, less solvent is needed for the wipe, lowering the VOCs that workers breathe. Alcohol-based wax and grease removers and soap-paste wax and grease removers are also effective and are among the least toxic solvent cleaners. Another alternative is to use biodegradable citrus or terpene cleaners for cleaning, degreasing and dewaxing. Terpene solvents are derived from natural sources such as pine and citrus oils. Your supplier may be a good source of alternative cleaners.
Some two-part adhesives contain isocyanates or epoxies. Your supplier may know of some safer alternatives. In the meantime, use gloves and good ventilation.
Use paints containing high solids and low volatile organic compounds (VOCs). Today, the paint manufacturers are lowering VOCs in their products and most now offer low VOC paints. Check with your supplier to see if you are using the lowest VOC paints for your needs. High solid paints also have a better transfer rate, thereby saving paint and money. Metallic tints can contain heavy metals such as lead, arsenic, cadmium and chromium. Again, ask your supplier for alterrnatives with less heavy metal content.
Water based paints
Water-based paints are available! They have much lower solvent content and are widely used in some parts of the US. Water based paints cover better, usually requiring 2 – 3 coats. Better blends and matches can be achieved, and storage, mixing and spraying are easier using these paints. Some equipment changes may be needed to use the water-based paints. The process requires a semi- or full downdraft booth and a set of venturi nozzles for the gun [or HVLP gun] to speed the paint drying process. The VOC content of the color coat can be reduced an average 5.5 lbs/gallon (as sprayed) to an average of 0.8 lbs/gallon (as sprayed) using the water-based system. [This information was gathered, as a case study by the CT DEP, at Executive Auto Body in Wallingford, CT. They are currently spraying about 15 – 20% of their work using water-based paints. Read more…]
Primers that are water-based and isocyanate-free are on the market. This is an ideal product to use to limit worker exposure to isocyanate, which can cause asthma, especially if priming is done outside the booth. While the person priming may be protected, there is a good chance that any other workers in the area of the priming will not be protected. Some of these primers require drying under infrared lights for 5 to 10 minutes. Many of them can be used on flexible parts without the need for a flex agent. Work with your paint supplier to select safer products that work for you.
A sealer coat normally contains an isocyanate hardener. Some systems do not require a sealer coat over primer. If a sealer is required, try to find a sealer that does not need an isocyanate containing hardener.
“Slime” can be used for masking a car. The big advantage is that it limits solid waste – the plastic sheet normally placed over a vehicle is eliminated and the “slime” is simply washed off with clean water. Slime is a soap product, solvent-free and environmentally safe. However, the disposal of the slime containing paint overspray may cause problems in sewage systems or ground water.
Use an HVLP spray gun – in CT it is required by law and eventually it will probably be required by all states. The transfer rate is much better than conventional guns. Less coating is used and worker exposure is reduced with less overspray. Transfer efficiencies of 70% or more are possible for a well-trained painter using an HVLP gun.
Smaller gun cups
If you use a smaller paint cup on the spray gun for smaller jobs, there will be less to clean. Use gun cup liners and there will be even less to clean, although more to throw away. Teflon paint cups are available to facilitate cleaning. These products will result in less gun cleaning solvent used and less VOCs in the air.
Use dirty solvent first as a prewash when cleaning spray guns, then use clean solvent. This will limit the total amount of solvent used. Try to replace the solvent with a less toxic material, such as those suggested in Solvent Wiping above.
Consider alternative shop cleaning methods. Lower airborne dust by vacuuming instead of dry sweeping or blowing off dust with compressed air.