Aluminum Anodizing

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801-972-2146

info@pilkingtonmetalfinishing.com
1225 S. Legacy View St.
Salt Lake City, Utah 84104
P.O. Box 25657
Salt Lake City, Utah 84125-0657

CERTIFICATIONS

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CERTIFICATIONS

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DOWNLOAD LITERATURE

Descriptive, print-ready pages for engineers and purchasing agents.

DESCRIPTION

Bright Dip is an anodizing method using a specific etch to achieve bright and shining appearance.

Bright Dip is the ultimate look in cosmetic anodizing. The natural glossy appearance of aluminum is highlighted through a chemical pretreatment done prior to the anodizing process. This pretreatment we call bright dip has a polishing effect, augmenting the inherent shine of the aluminum. However, the resulting brightness of the finished product is dependent on the condition and surface finish of the original part.

APPEARANCE

Brightens, strengthens and parts are then dyed brilliant colors. This process enhances the natural glossy appearance of aluminum and achieves a highly reflective surface finish similar to mechanical polishing. The degree of brightness is dependent on the type of alloy as well as the surface finish of the part.

Anodizing method that forms an extra thick layer of anodize. Also known as “Type III” anodize as referenced in military specification MIL-A-8625.

Hard anodizing can be made significantly thicker than standard anodizing (up to 3 mils) and is more dense. By increasing the anodizing thickness, products become more resistant to wear and corrosion. This also increases the electrical and thermal insulating properties of the product. Because the anodize is also more dense, it retains dyes and sealants better. With the increased hardness however, the finish does become more brittle.

APPEARANCE

While the hard coat anodizing process strengthens the aluminum, the product still largely maintains its natural metal appearance. Hard coat leaves a thicker anodized coating and is more dull in appearance than bright dip or standard anodize. Also, hard coat anodize is not sealed by default, and can therefore feel tacky.

Standard anodizing process using sulfuric acid. Also known as “satin” or “Type II” anodize as referenced in military specification MIL-A-8625.

The anodizing process develops the layer of natural aluminum oxide into a stable, hexagonal structure that is porous. Sometimes called an anodic film, the anodize is not applied like other coatings. An electrical current is applied using a cathode, while the aluminum product acts as the anode. Due to this process of formation, the exact thickness of the anodize is variable- ranging from .0005”-.002”. Because the anodize develops like grass in the dirt (growing both up and down) the overall effect on part dimension is minimal.

APPEARANCE

Because anodize is not applied like other coatings, the resulting appearance is largely dependent on the base aluminum. While the anodizing process strengthens and brightens the aluminum, the product still maintains its natural metal appearance. Various etches, dyes and sealants can be used to achieve a desired look.

FINISH SAMPLES

Please contact customer service and request a complete packet of our physical samples.

SIZE CAPABILITIES

PROCESS TANK SIZE NADCAP CERTIFIED
Sulfuric Acid Anodize 14' x 6' x 4' Yes
Hard Coat Anodize 7' x 4' x 3' Yes
Bright Dip Anodize 3' x 3' x 3' No
Boric Acid Anodize 7' x 4' x 3' Yes
Chromic Acid Anodize 7' x 4' x 3' Yes

PRINT CALLOUT GUIDE

The following are examples of finishing callouts that would be found on a print or purchase order and would indicate specific anodizing processes for a metal finisher like Pilkington Metal Finishing. These guides are meant for use by engineers and purchasing agents.

Note: If surfaces to be coated are not specified, all surfaces will be coated by default.

For bright dip with a clear anodize and default nickel acetate seal:

Chemically brighten surface and apply a sealed sulfuric acid anodize coating.

Options for color callout:

Chemically brighten surface and apply a sealed sulfuric acid anodize coating; Color Blue or Color match customer sample-001.

Note that color matching may be imprecise due to variation in alloys, anodize thickness, load time, load size and other factors.

Options for seal:

Chemically brighten surface and apply a sulfuric acid anodize coating; seal with RO Water or Do not seal.

For Certified Work per a Specification:

Click on the tip icon for detailed information

Chemically brighten surface and apply a sealed, Type II sulfuric acid anodize coating per MIL-A-8625.

Note that referencing specifications will often require additional processing, testing, and documentation of suppliers.

For a clear anodize with no seal:

Apply an unsealed sulfuric acid hard anodize coating.

Options for seal:

Apply a sulfuric acid hard anodize coating; seal with Nickel Acetate or seal with RO Water or Do not seal.

Note that Hard Coat is not sealed by default. Unsealed hard coat is harder than sealed hard coat, but it feels tacky to the touch.

Options for color callout:

Apply a sealed sulfuric acid hard anodize coating; Color Gray NL or Color match customer sample-001 or Color Pilkington Light Green.

Note that color matching may be imprecise due to variation in alloys, anodize thickness, load time, load size and other factors.

For Certified Work per a Specification:

Click on the tip icon for detailed information

Apply an unsealed, Type III sulfuric acid hard anodize per MIL-A-8625.

Note that referencing specifications will often require additional processing, testing, and documentation of suppliers.

For a clear anodize with default nickel acetate seal:

Apply a sealed sulfuric acid anodize coating.

Options for color callout:

Apply a sealed sulfuric acid anodize coating; Color Gray NL or Color match customer sample or Color Pilkington Light Green.

Note that color matching may be imprecise due to variation in alloys, anodize thickness, load time, load size and other factors.

Options for seal:

Apply a sulfuric acid anodize coating; seal with RO Water or Do not seal.

For Certified Work per a Specification:

Click on the tip icon for detailed information

Apply a sealed, Type II sulfuric acid anodize coating per MIL-A-8625.

Note that referencing specifications will often require additional processing, testing, and documentation of suppliers.

SPECIFICATIONS

The following is a list of applicable specifications for aluminum anodizing along with their title and issuer. Pilkington commonly processes to these specifications and is capable of processing to many more upon request.

SPECIFICATION TITLE CUSTOMER
AMS2469 Hard Anodic Coating on Aluminum and Aluminum Alloys Industry Standard
AMS2471 Anodic Treatment of Aluminum Alloys Sulfuric Acid Process, Undyed Coating Industry Standard
AAMA611 Voluntary Specification for Anodized Architectural Aluminum Boeing
ASTM B117 Standard Practice for Operating Salt Spray (Fog) Apparatus Industry Standard
BAC5022 Sulfuric Acid Anodic Films Boeing
BAC5632 Boric Acid – Sulfuric Acid Anodizing Boeing
BAC5821 Hard Anodizing Boeing
DPS9.314 Polishing & Texturing Aluminum Surfaces Boeing
DPS11.04 Hard Anodizing Aluminum Boeing
DPS11.05 Sulfuric Acid Anodizing Boeing
MIL-A-8625 Type I Chromic Acid Anodizing, conventional coatings produced from chromic acid bath Industry Standard
MIL-A-8625 Type IC Non-Chromic Acid Anodizing, for use as a non-chromate alternative for Type I and IB coatings Industry Standard
MIL-A-8625 Type II Sulfuric Acid Anodizing, conventional coatings produced from sulfuric acid bath Industry Standard
MIL-A-8625 Type IIB Thin Sulfuric Acid Anodizing, for use as a non-chromate alternative for Type I and IB coatings Industry Standard
MIL-A-8625 Type III Hard Anodic Coatings Industry Standard
P3100 Coatings per P3101 or P3102 optional – Anodic Coating for Aluminum and Aluminum Alloys Williams Intl.
P3102 Conventional Coating produced from a Chromic Acid Bath – Anodic Coating for Aluminum and Aluminum Alloys Williams Intl.
P3103 Hard Coating – Anodic Coating for Aluminum and Aluminum Alloys Williams Intl.

FREQUENTLY ASKED QUESTIONS

Q: What metals can be anodized?

While various forms of anodizing exist, Pilkington offers anodizing of aluminum. The presence of other metals will destroy the part and the chemicals in the process. Also, note that some aluminum alloys are more optimized for anodizing than others.

Q: Can you partially anodize a product?

Aluminum parts can be masked to exclude specific portions from the anodizing process. This is commonly done using fitted plugs on threaded holes or helicoils. The masking process for anodize is more involved that it would be for paint or other coatings, however.

Q: How long does the anodize coating last?

Clear anodize can last indefinitely under normal conditions. In fact, anodized aluminum is often used for architecural products because it is lightweight, won't rust, and doesn't peel. The color dyes used in anodizing will quicklly fade in the sun however; some colors more quickly than others. TAKE CAUTION when cleaning anodized aluminum. Many cleaning chemicals, such as Windex, can break down the seal and smudge the dye.

Q: How does anodizing change the dimensions of my product? How thick is an anodize coating?

Anodize is not a coating in the same sense that paint or powder is a coating. Anodizing forms a layer of aluminum oxide on the surface of the part. This layer can be anywhere from 0.5 to 2 mils (0.0002 to 0.0008 inches) in thickness, depending on the process. Pilkington uses thickness meters to accurately measure the thickness of the anodize.