Using Waterborne Paint - Hydrophobia

There's No Need to Fear Today's Line of Waterborne Paint

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It's been a long time coming, so we are really happy to finally be putting color on our '68 Camaro project car, Track Rat. Now, originally we were going to cover the car in a satin finish but found that the car would have looked great when first done, but it would have been all downhill from there. Get a scuff from a poorly placed cone and it's unlikely it will buff out. The same problem arises with environmental contaminants like bee pollen and gifts from our fine feathered friends. So we opted for something more durable, and that meant a traditional, high-gloss finish.

Back when we started this project, shops in California could still shoot solvent-based paints, but recent laws have forced them to switch over to waterborne paint systems. Like many new things, this change was met by apprehension from most shops. After all, most of the new "green" products out there might be better for planet Earth, but they tend to not work as well as their "dirtier" predecessors.

1306 Using Waterborne Paint Sketch 2/18

The truth is waterborne paint isn't really new. The technology has been around a long time. Heck, Western Europe made the switch to waterborne over a decade ago, and over 60 percent of new automobiles come from the factory with waterborne basecoats. In the case of what we're using, Cromax Pro, it's Axalta Coating Systems (formerly DuPont Performance Coatings) third generation of waterborne paint.

There are two other things to note. First, today only the basecoat is water-based. The primers, sealers, and clears are all just as they've been for a long time: solvent-based. The second tidbit is that waterborne basecoats aren't all water. Water replaces a large part of the solvents, but some solvent (about 10 percent) remains in the paint. This mixture of water and solvents acts as a carrier to move the color from the spray gun to the surface of the car. The water and solvents then evaporate, leaving behind the pigments and resins that give a car its color. The processes and techniques employed between the two systems are very similar. It's just that one sheds far fewer volatile organic compounds (VOC) into the atmosphere, which are harmful to the environment. Specifically, water-based paints give off almost 90 percent less VOCs compared to solvent.

The main difference between solvent and water-based paints is how they evaporate. The key with solvent is temperature, while water is driven more by humidity. Because of this, airflow is the key to faster drying times. The irony here is that the older cross-draft booths are better than the newer downdraft type. The reason is that as the water evaporates from the paint surface, the air molecules near the surface become saturated and can't hold more water, slowing the process. If air is kept moving across the surface that is drying, the saturated air is constantly being replaced with fresh air.

The equipment needed to switch from solvent to waterborne paint is fairly minimal. Stainless-steel spray guns are not optional and fans can be used, but it really only speeds up the drying process. Also, make sure the compressed air is clean since oil and water are known not to play nice together.

1306 Using Waterborne Paint In 3/18

The Axalta paint we chose is quite a bit different from other waterborne paints on the market. First, it uses a wet-on-wet process rather than the typical coat-flash-coat method. Secondly, it has a higher solid content (the color that's left behind once all the other stuff evaporates) of 20 percent compared with 15 percent in other brands. This means that less paint has the ability to cover more car. Using less paint saves money on the supply side, and not having to wait for the paint to flash means money is saved on the labor side. Also, due to the higher solid content, coverage can be attained in as little as 1.5 coats compared to the 3-6 coats needed with other paints. This results in a thinner film coating that Axalta claims makes Cromax Pro more resistant to stone chips.

Best of Show Coach Works in Escondido, California, was forced to make the switch to waterborne paint over two years ago. At first they were a bit reluctant, but after working with the product, they've found it superior to solvent-based paints in many regards. They've also noticed that the colors seem more vibrant, which is a very good thing when you're spraying custom cars. The biggest issue is that it's somewhat harder to do repairs on cars shot with solvent since the waterborne paint shoots so much cleaner. But as time ticks by and more shops move to waterborne paint technology, this will become as uncommon as coming across a car shot in lacquer.

01. With all of the bodywork done, Best of Show Coachworks' Jon Lindstrom did one final pass with 600-grit 3M paper. If the car wasn't going to get a sealer coat, he would have used 800 grit.

1306 Using Waterborne Paint 600 Grit 3m 4/18

02. All taped up and ready to go. One nice aspect of shooting a solid (i.e., non-metallic/pearl) is that panel orientation isn't critical since we didn't need to worry about how the flake or pearl would lay down, or "flop." It also meant we didn't need to worry about shooting all the panels at the same time. The parts not seen here will be shot later, once we have the Chassisworks subframe back under the car and the panels in place so that we can lay down the graphics.

1306 Using Waterborne Paint Car Taped 5/18

03. Before spraying, we made sure all of our seams were properly sealed with some Evercoat Maxim Flow Control. After all, it's not something we could do after painting.

1306 Using Waterborne Paint Evercoat Maxim Flow 6/18

04. In the paint booth, Jon used a lint-free towel and wiped the car down with some wax and grease remover.

1306 Using Waterborne Paint Use Lint Free 7/18

05. The last step before grabbing the paint gun, was to go over the Camaro with a Axalta Sontara Tack Cloth (PN E-4140). This helped to get the tiny bits and pieces off the body so it didn't contaminate the sealer.

1306 Using Waterborne Paint Axalta Sontara Tack 8/18

06. The Axalta Premier Sealer is a three-part system and was mixed at a ratio of four parts sealer to one part Reactive Reducer and one part Activator Reducer.

1306 Using Waterborne Paint Axalta Premier 9/18

07. Axalta has come up with a system for their sealers called Value Shading. The theory is that a color is described by three dimensions: hue, saturation, and value. Hue describes the dominant wavelength or "color" (e.g., green, red, or blue). Saturation describes the purity of the color, or how much the color has been diluted with white. Value, or tone, describes the brightness or darkness of the color. Value is the element of color that most controls the number of coats needed to achieve full coverage. The Value Shade for our particular color of blue turned out to be four.

1306 Using Waterborne Paint Axalta Value Shading 10/18

08. By using a primer/sealer that is pigmented to the correct value (shades of gray from light to dark), the number of coats to get full coverage can be greatly reduced, and less paint equates to a lower cost in materials. Even though this is less important with a high-solids waterborne paint like Cromax Pro compared to solvent-based systems, it still helps. Here, Jon lays down a nice coat of sealer. As always, he starts at the top and works his way down and around the car.

1306 Using Waterborne Paint Lay Down Coat Of 11/18

09. One common misconception about waterborne paint is that the whole system is water-based rather than solvent. This isn't the case. Only the actual color, or basecoat, is waterborne. The rest, such as the sealer and clearcoat, are traditional solvent-based products. Still, shooting waterborne does require a stainless gun so it doesn't develop rust. For this job, Jon busted out his Iwata stainless LPH400 gun. The orange tip is what he uses for basecoats and sealers. Expect to pay between $400 and $500 for a gun of this caliber and the tip, or air cap, is another $130.

1306 Using Waterborne Paint Iwata Stainless Lph400 12/18

10. When paint sits around it can separate with the pigments settling to the bottom of the can. Obviously this is bad, so we tossed our paint on the shaker to get it all mixed up proper like. Our color was chosen off of Axalta's Spectramaster Color Atlas and the code is CAS471. Now, be forewarned that the color you see on the little 1-inch square may or may not look the same when it's covering an entire car.

1306 Using Waterborne Paint Put Paint On The 13/18

11. The color we were trying to nab was one we saw on a '53 Porsche, which they called Azure Blue, and since we've been swamped, we didn't get a chance to do a spray-out panel before shooting the entire car. Let's just say we got real nervous when Jon started laying out the first coat of what looked like Neon Aqua Blue.

1306 Using Waterborne Paint Azure Blue 14/18

12. The way waterborne paint changes shades as it dries is a lot different than how solvent paint does. Here you can see the huge color difference between the wet area (that's shiny) and the drier area that is more matte. Cromax Pro utilizes a wet-on-wet application process. This means there's no need to let the first coat of color flash before shooting subsequent coats. Also, due to a higher solids composition, you can achieve full coverage in as little as one and a half coats. This saves money since most painters typically lay down four or more coats of color when using solvent-based and some other brands of waterborne paints. Even so, Jon laid down two and a half full coats just to be on the safe side.

1306 Using Waterborne Paint Wet Area And Drier Area 15/18

13. With the basecoat color laid down, we let it dry for 15 minutes before moving onto the clearcoats. The main difference between water and solvent is the way the carrier evaporates. With solvent, the evaporation rate is mainly driven by temperature. This is why there are a variety of reducers. High-temp reducers slow the evaporation rate down so that the paint doesn't dry too fast, while low-temp reducers speed up the evaporation rate to make the paint dry faster when the temp drops. With water the evaporation rate is driven by relative humidity and temperature. If the air is drier, the water leaves the paint film faster. Here "desert" controllers slow down evaporation when the air is very dry and standard or high-humidity controllers speed up the process when the air is very humid. With waterborne, air movement is key since still air becomes saturated and slows down the evaporation of the water.

1306 Using Waterborne Paint Let Basecoat Color 16/18

14. While the color was drying in the booth Jon started mixing up the clear. The Axalta Premier Clear is a two-part system that is mixed at a ratio of three parts clear to one part activator.

1306 Using Waterborne Paint Axalta Premier 17/18

15. Three heavy coats of clear later and the body of our Camaro was looking good. This go-round we only shot the body and doors. Later, we'll tackle the fenders and other parts, which will incorporate the graphics designed by Ben Hermance.

1306 Using Waterborne Paint Three Heavy Coats Of 18/18


Best of Show Coachworks
San Marcos, CA 92069
3M Corporate Headquarters
St. Paul, MN 55144
Sacramento, CA
Axalta Coating Systems
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