Читать книгу Patina - Kevin Tetz - Страница 8

CHAPTER 2

FINDING YOUR LIGHT!

Sunlight brings with it much of what is needed to deteriorate any surface over time: ultraviolet energy. Man-made surfaces, particularly painted surfaces, are susceptible to UV damage that manifests in what we refer to as patina. This energy from the sun gives us a clue and great direction as to how to emulate organic patina.

Everything exposed to our atmosphere is subject to chemical changes and breakdown. Metals rust and plastics deteriorate, and paint is no different. In order to understand how paint deteriorates, we need to know a little about its history as well as its chemistry.

History and Chemistry

Paint systems break down on a molecular level and oxygenate (a $3 word for fade). What actually happens is a layer is formed between the paint film and the atmosphere, covering up the paint and changing its appearance. Different paint chemistry has different reactions to atmosphere: older paint systems that have more heavy metals, different resins and binders, and less film thickness will show fading differently than a modern basecoat clearcoat system.

The Studebaker Brothers Manufacturing Company in South Bend, Indiana, used to advertise with pride that the process of painting a carriage took 52 days to complete. This was due to the steps of applying, sanding, and reapplying paint, allowing ample dry time for the finish to be as beautiful as it was strong. Then in 1921, nitrocellulose lacquer was accidentally invented. This invention (or discovery, depending on how you look at history) gave paint enough viscosity to withstand spray application, revolutionizing the way a paint finish is applied. A 1924 Pontiac was the first car that was spray-painted.

Compared to today’s paint finishes, the lacquer systems of the 1920s and 1930s were very weak. But coatings became stronger as innovations were introduced. During World War II, European paint manufacturers were restricted as to what chemicals they could use for coatings. They had to steer away from cotton-derived paints, such as nitrocellulose paints, due to the limited availability of cotton. Instead, they focused on plastic- and petroleum-based technology, which eventually became standard due to its superior strength and durability. To this day, the United States is led by European innovation in paint technology.

In the 1930s, most vehicles were painted with simple colors that were rather dull compared to today’s palate. Colors tended to be drab and similar to some primers, which explains why there is not a big contrast between the color itself and the rusted panel where paint has faded and worn through.

Metallic specialty colors started appearing on cars in the 1930s. The sparkly paint was first derived from fish scales that were mixed into pigment and resin bases. These paints and colors were not seen on mass-produced vehicles because they were very expensive to create and apply. They were only applied to upscale automobiles.

A less-expensive option was brought into mainstream automotive production in the early 1950s by Alcoa Aluminum. It produced the metallic effect by adding aluminum flakes to paint colors, which is still an effect additive in today’s paint systems. Aluminum oxide, plastic media, and other bright additives intermix with the resin as you build the layers of the paint job, giving dimension that wouldn’t otherwise be possible in a solid color. Decades-old metallic paint becomes rather chalky looking and uneven. It is challenging to replicate this look into fauxtina, but if done correctly, it can be a great effect.

This is the original and faded paint on the hood of a 2000 F150 truck. The gloss is completely gone, and the clearcoat has deteriorated to the point that it is flaking off in multiple places. An easy way to tell if it’s a clearcoat paint job is if the oxidation is white, regardless of the base color.

This is an example of a non-factory finish that is delaminating. The clear is still “clear” for the most part, but it is clearly separating from the base color. Once this happens, there’s no saving the paint. To repair it, it has to be stripped to the primer or bare substrate and redone.

This 1964 Ford was abandoned for decades, as the state of deterioration and original and horribly neglected single-stage paint finish shows. This was originally a bright red color, but it has turned to a hazy dark orange that can never be brought back to its former gloss. Notice that it fades within the range of color it started as and does not oxidize white as a clearcoat finish will.

Here’s another great example of patina to emulate. The original paint has faded to the point of revealing the substrate to the elements and atmosphere. Despite the rusty appearance, this is still mild surface rust that hides a relatively solid panel under the oxidation. The flaking paint under the trim is interesting, and the rust streaks that run down into the white are authentic. This Studebaker is complete with many valuable parts, including the acrylic ornaments on the fender peaks.

This 1937 Ford sports an updated interior and drivetrain but completely original paint and trim. Wear and deterioration of the paint are extreme, but the underlying sheet metal doesn’t seem to have been affected much.

It’s difficult to see the blue topcoat color that once covered the black undercoat on this 1951 Ford. The light blue metallic paint has been photochemically stripped off of the top surfaces, revealing the undercoat and the bare sheet metal of the fender.

Metallics, such as this one from a mid-1960s Buick, have aluminum flakes and pigment mixed into the resin base. Aluminum oxidizes very quickly once exposed to damaging UV rays, and it can overtake the pigment, as it’s done here, giving the blue color a very silvery appearance.

Automotive paint color trends come and go in phases that are sometimes driven by technology and sometimes driven by social and cultural swings. Often, auto manufacturers create new colors and styles in anticipation of a color trend catching on and becoming popular. In the 1920s, some vehicle manufacturers created vivid paint jobs. Using lively primary colors defied the depression era by showing an attractive, shiny vehicle that ignored the socioeconomic effects of the Great Depression. Bright colors were a clever marketing strategy, but it was not intended for the majority of mass-produced vehicles.

The 1940s showed us a lot more chrome and stainless steel trim, as well as single-colored cars. In the 1950s, mass-produced vehicles used aluminum-infused topcoat colors that had a more subtle metallic appearance. The metallic particles compromised the color strength and made these colors particularly susceptible to UV damage.

The cars of the 1970s featured a lot of earth tones, dark gold, bronze, and brown. For several years in the mid 1990s, a high percentage of new vehicles were produced in green colors. In 2015, dark brown made a huge comeback with manufacturers, particularly import carmakers. As paint technology continued to progress, so has the depth and complexity of paint colors.

Oxidation

New paint has a distinctly clean look to it; it is glossy and has a sharp distinctness of image (DOI), which is a statement on the quality of the reflection. For example, a glass mirror has a nearly perfect DOI, whereas most new-car paint jobs have an orange-peel look to the surface that gives a slightly distorted reflection. Aged paint typically has a poor DOI because of the oxidation that occurs on the surface.

This 1934 Packard represents a time in America when money was scarce and cars like this were very expensive. Vivid colors were sometimes chosen as a marketing tool to lift the spirits of consumers, and they were an incentive to discriminating buyers.

We obviously have a rusty truck that is slowly being reclaimed by nature. The paint color and the rusted metal are very similar, so is the paint rusty? In a sense, yes, it is. When you break down exactly what rust is and how similar the fading process is to the rusting process, it’s pretty safe to say that, in fact, paint rusts.

The DOI on this newly painted Jaguar is outstanding. This clearcoated finish has been sanded, leveled, and polished back to a mirror gloss. You can see by the crisp reflections of the lights and details in the paint that a lot of time and effort was spent perfecting this paint job.

This early 1960s F150 shows neglected paint with no DOI at all. In fact, it actually looks like primer. Believe it or not, this paint can be brought back to somewhat of a shine. Due to the UV damage from years of exposure and neglect, it will never have its original shine and the strength of the paint itself is lost forever. Even after polishing and waxing, it will soon lose its gloss again.

Oxidation is a chemical reaction between the surface and the atmosphere. This creates a layer, or an opaque filter, between the color and the observer. The oxidized layer can be removed using polishing techniques and rubbing compounds that have fine abrasives embedded in them, which can bring the paint back to a high gloss most of the time.

Oxidation on paint is a close cousin to conventional rust, though it is different from the degraded iron oxide that happens with metal. The two processes are so close on a molecular chemical level that I always say that any substrate can rust! Air pollution is another factor in how paint and other surfaces degrade over time. If there’s a lot of a sulfide in the air due to industrial fallout, painted surfaces don’t last as long. It’s just an easy way of saying that surfaces degrade over time with UV and atmospheric exposure.

Think of oxidation as rust. Realizing that there are sometimes different layers of oxidation that react differently over time can help you recreate, accelerate, and mimic the effects of aging on paint. Solid, single-stage colors react much differently than clearcoated colors. Creating patina is essentially visualizing what nature does to certain coatings and colors and reverse engineering the process. The quality of the fauxtina is dependent on the research and execution of the artist doing the project.

How Paint Ages

Everyone knows that paint fades. Bright colors become muted, reds turn orangey, blues become lighter, and white typically yellows, But why? There’s more than one influence that makes paint fade. The chalkiness of old single-stage paint is typically due to UV exposure, but pollution and other chemicals in the atmosphere play a part as well. The powdery film that collects on older nonclearcoated paints can contain some of the pigment from the underlying paint, thereby giving it a slightly lighter color than the original paint.

Most cars from the 1930s to late 1970s had a single-stage paint job applied at the manufacturer. This shows you the layers of color and gloss that were engineered into one layer of paint. It’s easy to visualize how this can quickly deteriorate and fade, if not wear down to the primer layers with exposure to the atmosphere, pollution, and UV damage from the sun.

Automotive manufacturers began using two-stage paint systems during vehicle construction in the mid 1980s. They phased two-stage paint in as the main refinish system through the 1990s. Clearcoated paints take on very different characteristics when aged and degraded.

Since the clearcoat is designed as a UV barrier to the pigment, it typically keeps the chalky oxidation from forming. It does a better job of filtering the harmful UV rays that will also fade color. While the vivid colors may fade under the clearcoat, the clear layer will last much longer before it finally breaks down. Once it degrades, the clearcoat will allow oxidation under the surface layer of clearcoat, creating a whitening and bubbling effect that is quite unattractive. Degraded clearcoat turns milky white and begins to delaminate from the layer of color.

This cross-section represents a modern finish with a layer of clearcoat over the base color. Since the top layer is very strong and chemical resistant, the color will last longer, even when the clearcoat itself begins to degrade and lose gloss. However, once the clear layer loses strength and allows UV rays to deteriorate the color layer through the weakened clearcoat, the two layers can separate, causing delamination and peeling of the clear layer.

The actual color of the paint can give a clue as to where the pigment is going to shift. A color wheel is a universal representation of the spectrum of colors in the prism and how they transition from one to another. Within the color wheel are the three primary colors: blue, red, and yellow. All other colors are derived of shades of these three primary colors. You can look at a color wheel and see what direction a color takes on in relation to the three primary colors.

The top of the door frame gets more sun, which causes more of a chance of weakening and eventually peeling of clearcoat. Delamination of the clearcoat on an upper surface can be seen on this panel.

A color wheel is a valuable tool. It can show you how a color may fade and what to add to strengthen them or make them more vivid.

An easy way to remember all of the color tones in the spectrum of light is to memorize the acronym ROYGBIV (Roy-Gee-Biv). It is the first letters of red, orange, yellow, green, blue, indigo, and violet. It’s important to know these colors and the order in which they appear in the spectrum of light. The order of ROYGBIV provides clues to color direction, color fading, and especially color tinting. So, know it! Learn it! Love it!

The other element of a color wheel that is important to know is that the value, or intensity, of the color is lighter on the inside of this color wheel. This gives us another tool to determine what a faded color might look like as it gets older. Since we know that faded paint is lighter, we can use the color wheel to figure out what is an authentic color direction as well as an authentic value (intensity) to give the illusion of naturally faded paint.

For instance, turquoise is between green and blue but not quite yellow on the color wheel. That shows you the direction of the color from either of the primary colors that it is closest to (blue or yellow). Turquoise has a lot more green than yellow in it, so the color will most likely fade to green instead of yellow. The color will also be more green than blue, even though blue is strong in the blend of pigments. Add in a layer of chalky oxidation, and the chalk film diminishes the gloss and filters the color, creating a combination effect. Orange is between red and yellow. The tone of that orange will give you a clue as to whether it’s a reddish or dark orange or a yellower orange.

Using the Sun

There is one simple rule that will guide you in creating authentic patina regardless of your color or vehicle choice: Paint fades from the top down. Simply put, there will be more damage on the top surfaces of a vehicle regardless of the style, color, or chemistry of a given paint finish.

In general, all things exposed to the sun and UV rays degrade from the top down. The shingles on your roof get lighter, stained wood on handrails gets faded faster than the spindles under them, and even fruit ripens and colors differently at the tops of trees. The sugar content in cherries is much higher at the upper third of the tree than at the bottom, which is a direct result of being exposed to more sunlight. Horizontal surfaces also fade faster than vertical surfaces. So, the hood fades faster than the doors.

The paint on this Chrysler fades from green to grey to red oxide. The upper exposed edges are recipients of most of the UV damage.

This truck has obvious color deterioration on the top of the fender. The flat part of the hood shares the same fate, but the vertical surfaces kept the color intact.

This rule provides an excellent starting point for designing the fauxtina for your project. It can help you look for the most accurate original color, and it will give you a range of patina examples to emulate.

Creating Character

If you’re not sure about the history of your vehicle, you can use your imagination and create possible scenarios that might explain the patina: Is it a barn find? Is it an abandoned vehicle found in the Arizona desert? Both of those conditions have a very specific type and severity of patina that you can recreate with some research and practice.

Studying how patina is different in specific geographies and conditions is important. It will give you the tools to carefully and authentically create a great conversation piece, a paint job that is a ton of fun to create, and a vehicle that you will be proud to display.

The hood on this truck is mostly faded to metal, but it’s uneven from side to side. This can be for a number of reasons. One reason could be that perhaps the truck was sitting partially covered.