When utilities are looking for guidance to replace faded signs I often get asked, “What are the most durable sign materials?”

The durability of outdoor signs is limited by the conditions present in the application environment.

These conditions can include chemical exposure, abrasion, temperature extremes, impact, bending, and even incentive towards theft due to scrap value.

In most typical outdoor applications, the common and most important factor limiting durability is UV degradation from sunlight.

Two of Electromark’s most durable sign materials include porcelain and fiberglass.


Unlike aluminum or other metal signs having a painted background and using conventional screen printed inks for the graphics, porcelain signs use vitreous (glass) coatings for both the background and printed graphics.

A porcelain base coat is first applied to a metal substrate and fired in a kiln at temperatures high enough to melt and fuse the coating to the metal.

This may be best understood as being the same as what I assume most of us would be familiar with perhaps from a school or other ceramics class, whereby we glaze and fire a clay pot.

Similarly, porcelain enamel sign graphics are composed of a glass-based inorganic pigment mixture stenciled onto the porcelain coated surface.

Like the porcelain base coat, each color is fired in a kiln and fuses with the base coat to become one with the sign.

Unlike competitors’ signs that use more common and corrosion prone low-carbon base steel substrates, Electromark exclusively uses non-corrosive stainless steel. Rusty Porcelain 2

This provides a major outdoor durability performance advantage; as chips in the porcelain coating, or edges where the coating is typically thin, expose vulnerable base metals to being corroded away right from under the vitreous coating.

An example of a porcelain sign using common rust-prone metal is shown on the right.

Electromark’s porcelain sign carries a 30-year warranty, and porcelain signs can last 50 years or longer.

In addition, Electromark’s porcelain signs offer very high heat resistance (up to 1400°F for short periods), and exceptional resistance to abrasion/scratching, chemicals, and corrosion.


Electromark’s fiberglass sign is a special paper screen printed with outdoor durnew fiberglass-01able inks, which is then embedded between layers of fiberglass cloth.

This sandwich construction is impregnated with a UV resistant liquid plastic resin that penetrates the fiber cloth along with the printed paper; essentially fusing the three layers as one.

Fiberglass is extremely tough due to the strengthening effect of the glass fibers, and the graphic is protected from weathering elements because it is literally embedded within the sign construction.

Electromark’s fiberglass sign carries a 20-year warranty and is supported by demonstrated field service history of greater than 25 years with no reported failures.

In addition, Electromark’s fiberglass sign offers exceptional chemical resistance, impact resistance, and cold weather performance.


Electromark offers five primary sign materials: porcelain, fiberglass, solar grade polycarbonate (Lexan), aluminum and polyethylene.

Although each material is selected for use in outdoor environments, materials vary in price, weathering performance, and each may offer certain performance features and advantages over others.

If you need help choosing between one of our five materials email us at csr@electromark.com.

Visit the Electromark website to learn more about the Electromark Advantage. Follow us on LinkedIn for new information and updates here: Electromark Company.