types of metal finishes

Metal finishes are commonly used to create an aesthetic appearance that comes with outstanding physical benefits. How many types of metal finishes are there? What are the advantages and disadvantages of each type?

Metal finishing is a broad range of processes that cover the surface of a metal to achieve desired benefits, characteristics, and properties. Any type of metal finish has the same general purposes, including preventing corrosion and rust, adding strength, and maintaining long term beauty. Now let's start exploring the popular types of finishes for metal.

Painting

Painting is adding liquid to metal by brushing

The traditional way of adding liquid to metal is painting
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Painting is the traditional way of applying liquid to metal by brushing, spraying, or dipping. The paint varies from solvent based to solid-based paints. The paint is air-dried naturally or placed in an oven.

Types of paint finishes for metal have many advantages, such as:

  • Diverse colors and high personalization
  • Often has a low initial cost
  • There is no need for an oven to dry.
  • Easy to achieve a high-gloss finish

Besides, it also has disadvantages, such as:

  • It easily peels off over time and needs to be touched up.
  • The paint layer is highly flammable and can cause damage and danger.
  • Harmful gasses, such as VOCs from traditional wet paint, especially in closed spaces.

E-Coating

E-coating strengthens a metal against rust and corrosion
E-coating is a wet method where parts are cured in an oven after being dipped in a paint liquid
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Electroplating, also called electrodeposition or e-coat, is a metal finishing process by coating a metal or alloy on top of another metal object, called a substrate. The base material is usually lighter such as copper or nickel. To optimize strength and conductivity, manufacturers often layer multiple layers of metal. They can be brass, copper, gold, iron, silver, titanium, zinc, and nickel.

The process of electroplating strengthens a metal against rust and corrosion. It's frequently used to finish pots and pans, sink taps, tin cans, coins, jewelry, and car parts.

However, e-coat does not come in a variety of colors, usually only available in black or white, and is not stable to UV rays.

Polishing

Polishing includes mechanical polishing, chemical polishing, and electropolishing

Metal polishing includes mechanical polishing, chemical polishing, and electropolishing
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Polishing removes surface imperfections, improves appearance, and is relatively cost-effective. It is not just one of the popular types of metal finishes for furniture; it is also used in everyday life, such as polishing jewelry, watches, and eyeglasses. Metal polishing includes 3 main types:

  • Mechanical polishing: Uses polishing wheels, belts, or pads
  • Chemical polishing: Immerses the metal in a chemical solution that dissolves the surface layer, resulting in a smooth and even finish without mechanical abrasion.
  • Electropolishing: Uses an electric current and a chemical bath to remove microscopic surface irregularities, creating a highly polished and reflective finish.

This method helps create a smooth, shiny surface, provides abrasion resistance, reduces friction, and enhances electrical conductivity in some cases. It is also easy to clean and prevents dirt build-up.

Some disadvantages of polishing are:

  • Take a lot of time depending on size and shape
  • May not be suitable for thin metal products
  • Limited abrasion resistance
  • Need skilled workers, otherwise, it is easy to damage or deform the product

Anodizing

Anodizing has anti-rust and anti-corrosion properties

Anodizing has outstanding anti-rust and anti-corrosion properties
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Anodizing is an electrochemical procedure by soaking it in chromic acid electrolyte and passing an electric current through it to oxidize the outer layer of a metal. It is mainly used for aluminum, magnesium, titanium, and zinc parts.

This method has outstanding anti-rust and anti-corrosion properties, improving hardness and scratches significantly. However, it is not suitable for all metals, can increase size due to acid expansion, and requires specialized equipment and expertise to perform safely.

Powder Coating

Powder coating is the most popular applied in furniture

Powder coating is the most popular applied in the furniture field
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Powder coating is the most popular of the different types of metal finishes. Powder coating is a metal finishing process using a dry powder. Dry powder contains various ingredients, including pigments, treatment agents, leveling agents, and other additives.

The powder coating process starts with powder coating the metal, which is then cured with UV light or heat to ensure an even coating and finally hardens in an oven to create a protective layer.

This coating method is cleaner, faster, more durable, aesthetic, economical, and environmentally friendly. It is also resistant to chemicals, moisture, ultraviolet light, and other extreme weather conditions, so it is very suitable for outdoor products such as metal table legs and chair legs.

But it still has some disadvantages, like:

  • Production costs are high because the powder coating process requires specialized equipment such as spray guns, booths, curing ovens, and a carefully controlled environment.
  • The color range is limited because it cannot mix colors like liquid paint. It is also difficult to adjust and remove if the wrong color is sprayed.

Galvanizing

Galvanizing is submerging metals in molten zinc to form a thick protective layer

Galvanizing is submerging metals in molten zinc heated to 460-480 °C to form a thick protective layer
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Galvanizing involves submerging metals in molten zinc heated to 860-900 °F (460-480 °C) to form a thick protective layer. To preserve the underlying material, the zinc coating acts as a barrier between the metal and any corrosive chemicals that may come into contact with it.

Galvanizing metal is a durable, high quality protective layer that resists corrosion and rust, making it ideal for manufacturing equipment for use in commercial, agriculture, oil and gas, and consumer goods.

However, galvanizing is relatively expensive and comes in only one color. It also becomes brittle over time due to high temperatures or humidity, causing it to lose its protective properties.

Abrasive Blasting

Abrasive blasting uses high-pressure air to blow a stream of abrasive material onto the surface of a metal
Using high-pressure air, abrasive material is blasted into a metal surface during an abrasive blasting process
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Abrasive blasting uses high-pressure air to blow a stream of abrasive material onto the surface of a metal. Corn cobs, steel shot, aluminum oxide, sand, plastic grit, silicon carbide, carbon grit, or glass beads are some examples of abrasive materials. The surface will differ according to the substance used; glass beads give the object a more satin appearance, while aluminum oxide leaves a matte surface.

Abrasive blasting helps:

  • Eliminate surface impurities
  • Result in a tidy and seamless finish
  • Modify the form or expand the surface area
  • Treat the surface in preparation for plating, painting, or coating

However, sandblasting creates a lot of dust and noise, affecting health. It also requires considerable expertise and may not be suitable for all metals.

Understanding the various types of metal finishes and their pros and cons helps you choose the most suitable option for your needs. If you love powder coated metal table legs, Flowyline is a destination worth! Don't hesitate to contact us via email at customerservice@flowyline.com or call directly at 1 (323) 990-2487 to get your questions answered and custom support as desired.

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