A quick glance around any city street will reveal the ubiquity of metal. You may see a wrought iron fence enclosing a public park, like the metal pickets with welded tops that surround Bowling Green in lower Manhattan, notably the city’s oldest fence; a monument to modern inventions that have been eclipsed by subsequent generations, such as the United Kingdom’s iconic red telephone boxes, the ornate lamp posts in Paris, the City of Light. But most of all you will see metal signs. The array of metal signs comes together to give meaning to space and place. Street and transportation sign systems, informative wayfinding signs, eclectic collections of custom metal signs for businesses and residences. As a whole they give a city or town its distinctive identity.


Known for its durability, metal has been widely used as a base material for signs. Cast iron road signs and markers with embossed lettering were standard in the 19th century and into the 20th century, particularly in Great Britain and the United States. Today, steel and aluminum are the most common metals used in metal sign fabrication. Each of these two materials have advantages and disadvantages.


Perhaps the most versatile base for signs, steel is sturdy and economical. Metal wall signs made of steel have to be mounted with care. Unlike lightweight aluminum, the steel requires adequate reinforcement, particularly with large format signs. Protection from rust is a consideration for steel signs, but special treatments, such as galvanizing and coatings, solve this issue.


One-third the weight of steel, aluminum has rust resistant properties. Colors can be dyed directly onto the surface and some dips can give the metal a highly reflective quality. However, aluminum can have some limitations when it comes to specific surface treatments. But, overall, it is a popular and flexible material for signs and sign systems.


The fabrication technique depends on the type of metal and the desired look and feel of the messages and images. In general, most metal sign fabrication begins with the application of a surface treatment, often a background color. Once the surface has been coated, the sign’s information can be applied. A number of techniques can be used for messaging, including stenciling, die-cutting, and adhesive films and decals. The staying power of the lettering and graphics will vary, depending on the treatment.


Because metal needs protection, a basic finish is standard in the sign fabrication industry. Finishes can also make a metal sign eye-catching, a desired feature for environmental signage.

The most frequently used coatings on metal signs include three enamel finishes: baked enamel, air dry enamel, and porcelain enamel. Although all these coverings contain the word enamel, each of these finishes have their own application requirements and visual characteristics (see the below overview).

Overview of Enamel Finishes

Air Dry Enamel Baked Enamel Porcelain Enamel
How it's applied Sprayed on (procedure similar as baked enamel) A melamine-base coating is sprayed on using an air fluid or airless spray method A mix of inorganic material (frit) and water is sprayed on to the surface
Catalysts Air dry (kiln heating can be done, but requires precision to avoid vaporization) Heat (kiln at 250° F) Heat (kiln at 1000° F)
How it sets Surface film on metal Surface film on metal Integrates into the structure of the metal, which becomes porous when heated
What it’s best on Aluminum and steel (often used for metal signs that cannot fit in a standard sized kiln) Aluminum (a rust-inhibiting primer is needed for steel) Steel (aluminum may lose its shape at the high temperatures required to bake the porcelain enamel)
Hardness Less than baked enamel Very good Very good
Color matching Can use most paint matching systems Can use most paint matching systems Can use most paint matching systems, with some limitations
Tendency to fade Variable. Lighter colors last longer than darker colors Variable. Color and gloss are factors, with semigloss considered best finish. (High gloss and matte are less resistant to fade, therefore not recommended) Minimal to none. Some fade possible with reds, oranges and yellow when used outdoors, but known for its overall uniform longevity
How long it lasts 5-12 years 5-15 years 20-30+ years

About Ramsign

If you are interested in custom metal signs, it is best to consult an experienced sign fabricator to discuss your needs. Because there are a range of techniques, expert advice can help you determine the process that can best achieve the aesthetic and functional results you require. At Ramsign, we specialize in porcelain enamel coated metal wall signs. We use a steel base and manufacture every sign by hand. Contact us if you have a special design request or would like to learn more about our products.

If you would like to get some more information check our Metal Signs, Vintage Signs, Yard Signs, Scandinavian Design, and Door Signs inspirational posts.