Paint & Finishes

Over the years, the demand for a greater variety of finish types and colors for aluminum frames has resulted in new technologies with more choices. These new choices have complicated the selection of finishes. One finish may be more desirable than the next, depending on what characteristic you are looking for.

First some education on the two ways of applying a finish to aluminum: anodizing and painting.
Anodizing is an electrochemical process of converting the aluminum surface to aluminum oxide (controlled corrosion). Each extrusion is treated in a series of baths: 1. Cleaning   2. Etching  3. Desmutting  4. Anodizing  5. Coloring (if needed)  6. Sealing. Rinsing is done between each step to minimize chemicals being transferred into the next step.
The anodizing step involves passing an AC current through the extrusions, using the sulfuric acid as a medium. The oxide layer is formed and pores are created. For colors, the element is trapped in the pores then sealed. This process produces a hard surface that is long lasting, resists scratching and abrasion, and provides excellent protection from the sun's ultraviolet rays. Because this coating is an integral part of the aluminum, it will not peel or chalk, but, because the surface is still aluminum, it has minimum resistance to alkaline and acid. Galvanic Corrosion
An anodized finish can have a rich aluminum tone called clear anodized, or an earth tone color can be added. Anodizing gives aluminum a deeper, richer metallic appearance that is not possible with paint. Anodizing is less affected by sunlight than paint. Because of variables such as temperature, aluminum composition etc., slight variations in color and gloss will exist. This is to be expected, and it is important that this characteristic be considered when choosing anodizing. The unique process of anodizing reveals the natural character of extruded and fabricated aluminum, especially Clear Anodize. To accentuate the natural beauty of clear anodizing Fleetwood adds a unique, proprietary process before anodizing. The process manipulates the aluminum surface to soften "cooling lines" commonly found in most aluminum products. If exact color uniformity is required, painting is a better choice. One reason clear and dark bronze have become the industry standard anodized colors is because they have the least amount of color variation and are therefore easier to reproduce and match earlier batches.
The American Architectural Manufacturers Association (AAMA), in its performance specification AAMA 611, designates anodized coatings as Architectural Class I and Architectural Class II. They represent the thickness of the anodized coating. Commercial Class anodized material has an average of .2 mil coating thickness, while Class I is .7 mil or greater. Thicker anodized coatings are less susceptible to weathering and more resistant to corrosion and scratching. Fleetwood's stock Dark Bronze and Clear anodized are Class I.
To keep your anodized windows and doors looking new, follow Fleetwood's Care & Maintenance Instructions.
When considering anodizing over paint you have to be realistic about its nature. By nature, paint is consistent in finish color and sheen whereas anodizing is inconsistent in both. However, it is this irregularity that exudes the natural "character" of anodized finishes. As one looks at an anodized finish they are actually looking at the metal surface behind the finish whereas painting hides these imperfections. Get samples of both before you make your final decision. If a custom shade is desired (F1-F5), expect a full shade variation on each side of the ordered color. Our Authorized Dealers have samples to show you and upon request we will be happy to mail you some.
As illustrated in the three images below, even dark bronze anodizing appears to change color under different light and angles. The fourth image is of natural wood flooring that shows desired color changes from plank to plank. Similarly, anodizing is a natural material and is therefore an artistic finish.
      color variation1      color variation2      color variation3      wood flooring
Painting is where most of the advances in finishing technology have been developed in recent years. Fleetwood promotes only finishes that meet the AAMA 2605 specification, which is the best available in the market.
AAMA 2605 is the highest grade paint and is made with a fluoropolymer resin and marketed as 70% Kynar. Kynar paints are excellent in regard to retaining their color in harsh environments. They are typically applied in a two-coat system, but, depending on the color a third or even fourth coat may be required. These third and fourth coats are only needed for some exotic and metallic colors. Kynar paints also have a "Teflon" like surface and are easily cleaned.
Chemical resistance and resistance to sunlight are the strengths of Kynar coatings. Kynar paints are tested under the South Florida sun for durability and offer the best color, gloss retention and corrosion resistance. They are also the softest and will scratch or mar more easily than an anodized finish. Fleetwood offers thousands of standard Kynar colors that can be selected from most any paint catalog. Simply give Fleetwood the UC Number and it will be matched to your satisfaction. As well, Fleetwood offers designer colors that are created by you or your design team. Once you have created your unique color, Fleetwood only needs a physical sample.
When considering paint over anodizing you have to be realistic about its nature. By nature, paint is consistent in finish color and sheen whereas anodizing is inconsistent in both. However, it is this irregularity that exudes the natural "character" of anodized finishes. As one looks at an anodized finish they are actually looking at the metal surface behind the finish whereas painting hides these imperfections. Get samples of both before you make your final decision. Our Authorized Dealers have samples to show you and upon request we will be happy to mail you some.
Many factors have to be considered in the costs of each finish. Not only is there the cost of the actual coating, but also there is whether the window manufacturer considers that finish stock or custom. Stock finishes are what a manufacturer has on the factory floor. Material comes off the shelf, and any material that is left over goes back on the shelf.
Custom colors must be shipped to a custom finish applicator. Unused material that is not used gets scrapped. Applicators have minimum order requirements. Many painters have their own standard colors, and using one of them will not reduce cost but it will save time. Each custom color has its own recipe and when a new color is being formulated it takes an extra two weeks.
Custom colors requiring only two coats are the least expensive. Earth tones are the most popular color range offered in this system. Then come the bright whites and micas. Micas have a metallic look, and, because the sparkle is achieved by the use of pearlescent mica flakes, a third topcoat is not required.
Next in the scale of costs are the exotic and 'XL' metallic colors. Bright yellow, orange, blue, green, red (and more) are examples of exotic colors that require a third coat. Some very bright colors even require a fourth coat. Metallic colors that achieve their sparkle with aluminum flakes require a third coat.
Galvanic Corrosion
Galvanic Corrosion Defined: When two different metals are immersed in a corrosive solution, each will develop a corrosion potential. If the corrosion potential of the two metals is significantly different, and they are in direct contact and immersed in an electrolyte, the more noble metal will become the cathode and the more active metal will become the anode. A measurable current may flow between the anode and the cathode. The corrosion rate of the anode will be increased and the cathode decreased. The increased corrosion of the anode is called "galvanic corrosion". In the presence of an electrolyte such as moisture (especially salt water) the two metals are "bridged", forming an electrical couple. Once the couple is created there is an exchange of electrons. In layman's terms, one metal extracts mass from the other, thus causing corrosion. If you have ever seen a white chalky substance on thresholds you have seen galvanic corrosion.

In order for galvanic corrosion to occur, three elements are required. If any of these elements is missing, galvanic corrosion cannot occur. If, for example, the direct contact between the two metals is prevented (plastic washer, paint film etc.) there cannot be galvanic corrosion.
1) Dissimilar metals
2) Metal-to-metal contact
3) Metals in the same conduction solution (usually called an electrolyte)
The greater the corrosion potential of each metal (the more active or more noble) the greater the potential for corrosion. The "galvanic series" has been developed to list the various metals in order from most active to most noble:
Magnesium Anodic
Galvanized Steel

Mild Steel
Low Alloy Steel
Cast Iron
Muntz Metal
Yellow Brass
Red Brass
Aluminum Bronze
Stainless Steel (430)
Stainless Steel (304)
Stainless Steel (316)
Gold Cathodic
The greater the separation between the two metals listed, the greater the corrosion potential. For example, if zinc (think galvanized steel) which is an active material and near the top of the list and stainless steel, a noble metal and near the bottom of the list were in direct contact and in the presence of an electrolyte (water), galvanic corrosion will probably occur.

In addition to the three elements cited above, the relative area of each of the exposed metal surfaces is also a consideration (see Figure below). If the area of the cathode (noble metal) is very large, and the anode (active metal) is very small, the current produced is likely to be very high and the anode will corrode quickly. For example, if there is a window frame made of stainless steel and it is attached with carbon steel screws, the screws will probably corrode. If the area of the cathode (noble metal) is very small, and the anode (active metal) is very large, the current produced will be very low and the anode will corrode very slowly, if at all. If the window frame is made of carbon steel and it is attached with stainless steel screws there will be very little, if any, corrosion.

Dissimilar metal combinations should be avoided in areas where moisture is likely to accumulate and remain for long periods. In well drained exterior applications, dissimilar metals can be used together if favorable surface ratios exist, but the best solution is to electrically insulate one from the other. When painted carbon steel and stainless steel are welded together, the welded joint should be painted. Stainless steel fasteners with neoprene or other inert washers are regularly used with other metals.

The finish you choose should depend not only on color but also on environmental factors such as urban/industrial environments, high traffic areas, southern exposure, distance from the ocean, etc. No finish is perfect. Like everything else in life, there are tradeoffs. Color variety, color retention, abrasion resistance, environmental impact, alkaline / acid resistance, uniformity of finish and costs of these are all characteristics and properties of each type of finish that must be considered when choosing a finish. With a better understanding, you will be able to choose the best finish for your application.