Temperature, climate, booth technology and training should all play a part in the waterborne system you choose
Businesses in parts of California soon will need to choose a waterborne system. The easiest way to select a system is simply to go with the one that may already be in use. That might be the best way for most shops to go. Before making your decision, take the time to carefully and thoroughly consider the advantages or disadvantages of all the different systems available for your shop.
Factors that may affect this decision include: temperature, shelf life (before and after mixing), stability, disposal, cleaning, air movement, heat, special equipment, application technique, training, changeover support, warranty, color match and application speed.
Some of us were around when the industry changed from lacquer to urethane paint systems. I don't know of a single old-time painter who survived the transition who would like to go back to the old lacquer days. But change is difficult, and the more questions you ask before the transition takes place, the smoother your transition will be. Taking a good look at the variables, some that you know and others you may not have contemplated, will help when making the move to waterborne.
Temperature
In the past, many shops only considered temperature a work factor after they'd already mixed, reduced and then sprayed the paint onto a vehicle. With waterborne, where water is a primary ingredient, temperature becomes a far more critical matter.
Waterborne paints (toners and all) are adversely affected by cold. The first thing that should come to mind here is not letting waterborne products freeze. Most paint manufacturers already recommend that no paint be allowed to go below 40 degrees F from the point of manufacture until it is applied to the vehicle.Temperature control is such a sensitive issue that at least one manufacturer has attached a device on paint containers that changes color when the product becomes exposed to temperatures below the critical 40 degree F threshold. If the label indicator changes, the product cannot be used.
These products must be kept in an environment that stays above 40 degrees F during manufacturing, shipping (requiring heated trucks in some cases), storage at warehouses and jobber locations, and in the refinish shop. The temperature control issue might mean that shops in northern climates will need to keep the building temperature up during the night — at least in the area where paint products are stored. Knowing how the system you choose is affected by cold is one consideration that must be addressed up-front, even if you are located in a warm climate.
Shelf life/storage
Shelf life, the time extending from the manufacture date until the product best-used-by date, can be critical for different waterborne product lines. Some lines have a six-month shelf life. Some have a shelf life of two years while other companies say this factor "varies by toners." Whatever the case, shops need to keep a close eye on the best-used-by date. Also to be considered is the time a product must be used after mixing and after reduction. Some paint manufacturers state their products have a four-day pot life after reduction. Others state, "use upon RTS reduction." Still other manufacturers say their products will last three or six months when stored in a lined or plastic container.This raises an important point. Waterborne paints cannot be mixed or stored in containers with no liners. Some paint manufacturers use plastic containers for shipping. That makes the storage requirement obvious to most of us. However, other companies ship their products in what appears to be traditional steel cans. The insides of these cans are in fact lined. That might not be obvious to some employees. If waterborne paint is placed in older, un-lined cans in the shop, the inside of the cans will rust, ruining the coating. Lined containers are readily available to shops.
Stability
Stability was not an issue for coatings in the past. When toners arrived at the shop, we knew they had to be placed on the mixing bank and agitated for 15 minutes twice a day, per manufacturer recommendations. Some waterborne toners, though, do not separate and therefore do not need to be agitated to provide a proper color match. They may simply be taken off the shelf and poured. In fact, if these products are shaken, they can bubble and cause application problems.
Note too that the reduced color must be stirred before application. This is an important consideration when using waterborne products.
Depending on your operation, mixing machines, which often take up a large area of the mixing room, may no longer be needed (without the presence of a mixing machine, the requirements for explosion-proof elements are reduced).Previously, paints that were poured off without proper agitation could change the color of the toner. When that happened, all formulas mixed from the compromised toner could be off. With stable toners that don't need agitation, this problem no longer exists. Keep in mind that some manufacturers no longer recommend that mixed and reduced colors be placed on a paint shaker.
Disposal
Though disposal of hazardous waste has been part of the working routines for shops for years, the introduction of waterborne paint adds additional wrinkles to this task. In most areas of the country, waterborne hazardous waste and solvent hazardous waste cannot be mixed together. If you use a recycler for solvent-borne paints such as clear coats, you may continue doing so. However, waterborne products need to be cleaned in a dedicated waterborne cleaning machine.The waste generated by waterborne machines needs to be consolidated with a flocculating agent. This is a powdery agent added to the washing liquid that makes solids clump together so they can be strained out of the water. After the flocculated solids have been removed, the water can be reused a number of times (the number of times depends on the flocculating product). The waterborne waste can then be placed in a waterborne hazardous waste container and disposed of as mandated by your local area regulations.
Flocculation can reduce waterborne hazardous waste significantly. This is important since the cost of disposing of waterborne hazardous waste may be more than that for solvent waste. Check with your local hauler.
Cleaning
Cleaning a waterborne spray gun technically follows the same procedures used for cleaning solvent borne paint guns. Some technicians have found that waterborne paint may be a bit harder to get out of the gun. Just rinsing the gun with water may not be enough. The water used for reduction is not simple tap water. This water must be de-mineralized, de-ionized and include the necessary additives that reduce coatings.
Some questions you'll want to ask before cleaning a waterborne spray gun include: "Can I clean my equipment with tap water, and if not, can water that I produce from a reverse osmosis filter work for cleaning the equipment? Can this same water be used in the gun cleaner, or do I need to purchase special water for cleaning?"
Even when you answer these questions, you might still have some cleaning issues.
You also need to determine if the guns need to be broken down between each application or if a good rinse will be sufficient. You'll also need to determine how difficult it will be to remove products that remain in a gun and dry there.
Equipment needed
What equipment will your shop need? Issues such as the need for air movement and dedicated spray guns need to be addressed.
SPRAY GUNS: Though most paint manufacturers say special spray guns are not necessary, most agree that guns used for spraying solvents (for example, clear applications) should not be used for waterborne coatings. Rust is an issue. A spray gun that does not have stainless steel or coated fluid passages may be subject to rust from waterborne coatings. Look for guns that won't rust from water exposure. Dedicate those guns solely for spraying waterborne products. Note that the fluid tips and nozzles for guns used for waterborne products are the same as those used for spraying solvents.
AIR MOVEMENT: Air movement is critical when using waterborne coatings. Waterborne products evaporate and must have constant movement of air past the painted surfaces to facilitate this evaporation. Some paint manufacturers recommend as much as 200 cubic feet per minute (cfm) pass by the painted surface. This level of air movement is significantly higher than what most present day paint booths are capable of producing. Most likely, you will need to retrofit your booths to move enough air.
Air movement also is critical to avoid having moisture-heavy air collect around a paint job. When this saturated air collects, it prevents waterborne products from properly evaporating. Banks of venturies, which can be installed in the corners of the booths, can move air throughout the booth. Fans installed in the ceiling also can force more air movement than the original equipment provides.
While both of these methods can produce the necessary levels of air movement, they can be expensive. Permanent whole-booth devices can be the most convenient methods to move air. Many shops, however, have opted to use either hand held or "tree" mounted portable venturies. These banks of two or three venturies can be moved into place inside the booth and directed at the surface of the vehicle being painted, evaporating water from the surface for drying or application of subsequent coats.
Most paint manufacturers define flash time as the time it takes until the previous coat is uniformly dull, which can be 15 minutes or more in a conventional air movement booth. But in a booth with additional air movement, flash time could be only three to five minutes, which is a significant savings in production time.
Heat
Most waterborne paint manufacturers say that heat is not necessary for waterborne evaporation. Waterborne paint will not evaporate faster unless dry air is moved around it. Heat, on the other hand, will remain necessary for fast curing of solvent-borne clear coats.
Application
Spray applications for waterborne products are very similar to solvent-borne basecoats, with just a little twist. The first coats are put on in the same manner as solvent borne with a "control coat." The last coat is applied to control metallic lie and assure proper color match. This control coat is similar to a "letdown coat" that some painters use to control metallics in basecoats. In waterborne products, this coat helps to eliminate streaking and mottling paint.
Most paint manufacturers provide waterborne system products such as colorless blending coatings to help with wet bedding blending techniques, along with blending solvents, flop control, flattening agents and all the other specialty items shops have become accustomed to.
Most paint manufacturers provide two or three-day painter application classes during or before a shop's conversion to waterborne systems. The availability, location and level of training will help you decide which paint manufacturer to go to for your waterborne needs. Some manufacturers will perform training on-site so the transition to their waterborne product is smooth. Training in your shop with your equipment can provide better "transfer of knowledge" than training offered in an unfamiliar place. In-shop training also can significantly lessen the impact of switching systems on your production cycle.
Changeover support
Even with all the pertinent questions asked, new equipment in place and painters trained, the level of changeover support that a paint manufacturer provides still is critical. Having a manufacturer representative at your shop during a changeover will help you address such potential problem areas as color match, speed of application and warranty issues. Forming a good relation with your jobber and paint company representative will continue to be important to the long-term profitability of a refinish shop. Most paint manufacturers realize that the more profit you make, the more product you can buy and use. It's in their best interest to supply continual support to help your bottom line.
