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Anodizing vs Powder Coating: Choose the Best Aluminum Finish

Anodizing vs Powder Coating

Aluminum is one of the most commonly used metals for precision parts. Aluminum is lightweight, strong, and easy to machine. 

Oftentimes, manufacturers use a secondary process like anodizing or add a powder coating to increase the durability of the aluminum parts. These processes also add visual appeal to the parts.

These two processes have their own pros and cons, and use cases. This post will help you decide which finish is best for your aluminum parts.

What is anodizing?

Naturally, aluminum doesn’t rust, but it does corrode over time. Over time, a thin layer of oxidation forms on the outside of aluminum. This layer provides some protection from corrosion.

Anodizing is a chemical process that increases the layer of oxidation. The parts are placed in an electrolytic solution like sulfuric acid, and an electrical current is passed through the part. The increased oxidation layer increases the resistance to wear and corrosion, increases heat dissipation, and improves glue and primer adhesion.

Anodized aluminum usually has a matte finish. Natural dyes can also be added during the anodizing process, so different colors can be added to the parts. When the parts are colored, they have a more metallic finish. The color is also added under the surface of the part, so it can’t be scratched off.

What is powder coating?

Powder coating is a dry paint process done to add a decorative and durable coating to parts. After the parts are machined, they’re sprayed with a powder that attaches to the metal. Then the parts are heated or baked in an oven to cure the powder coating.

Powder coating offers a strong layer of protection, and the amount can be adjusted to add more or less. Powder coating is a very environmentally friendly form of finishing.

You can also adjust the look and color of powder coating, making it more or less glossy, and more or less textured.

Anodizing vs. Powder Coating

Both of these finishing options provide great physical and visual benefits. They do have some key differences that make them better for specific uses. Usually a part can’t be anodized and powder coated, so it’s best to choose one or the other. 

In some cases, anodized parts can be painted, but it’s not ideal.

Anodized Powder Coating
The anodized layer can be very thin, and only slightly change the part dimensions.
It’s very difficult to obtain a thin layer of powder coating.
Offers a variety of metallic colors and smooth finishes.
Offers a wide variety of colors and various textures.
With proper recycling processes, anodizing is very environmentally friendly.
No solvents are used in the process, making it very environmentally friendly.
Anodizing provides excellent wear, scratch, and corrosion resistance.
Good corrosion resistance, but it is more subject to wear and scratches than anodizing.
Resistant to color fading as long as the dye is UV resistant and it’s sealed properly.
Very resistant to color fading, even when exposed to constant UV light.
Anodizing makes the aluminum non-conductive.
Has limited electrical conductivity compared to bare aluminum.
Anodizing can be more expensive.
Powder coating is more cost-effective.

Is anodizing or powder coating cheaper?

Powder coating parts is usually less expensive than anodizing. Both processes are cost-efficient, and the coating lasts a long time. There are many factors that impact the price of both services. The part shape and size, coating thickness, dyes, and quantity of parts are all important to consider. Because anodizing won’t scratch off like powder coating, the costs can even out over time. 

Most companies will charge a minimum for anodizing and powder coating parts.

Common uses for each finish

Because these finishes offer great protection, you’ll see them both used on most aluminum consumer goods. Aluminum is a great metal to use, but adding a finish increases the longevity of the parts.

Anodized Powder Coating
Automotive parts
Automotive parts
Aerospace parts
Lawn equipment
Sporting goods
Outdoor equipment and furniture
Jewelry and artwork

Which aluminum finish should you choose?

Your choice of finish ultimately depends on how your part and product is going to be used. Anodizing and powder coating are both great finishing options for aluminum parts.

Anodizing is ideal if you need to maintain tight dimensionals. You’ll get excellent corrosion and wear resistance, and have an attractive metallic look without increasing the size of your part too much. Anodizing is also the better choice when your part needs to dissipate heat, or if you’ll be using any glue or primer on it.

Powder coating is the better option when you want vibrant colors and unique textures that will last. The coating will last even when exposed to the outside elements. Powder coating also offers good protection at a lower cost than anodizing.

Spex is an ISO 9001:2015 certified precision machine shop in Rochester, NY. We machine thousands of unique metal and polycarbonate parts every month for different industries around the world. Reach out to our team to see if we can help with your next project. 

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