Sheeting 101: Engineer Grade, Diamond Grade, High Intensity Prismatic… Clarification for the Confused.

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Since the advent of reflective sheeting in the 1930s (by 3M Corporation), scientific research has advanced this product component primarily used for highway signs, steadily improving brightness and visibility over time. First, Engineer Grade sheeting was introduced into the marketplace, followed by High Intensity and Diamond Grade. 3M has developed all grades of sheeting with prismatic technology, providing brighter, longer-lasting signs for the motoring public.

Sheeting 4

When determining which sheeting type to utilize in highway sign fabrication, several concerns come to mind. Will the sheeting meet the specs required for that particular type sign? What about longevity in the field?

– Engineer Grade Prismatic (EGP) has no warranty, and has a life expectancy of five to seven years.

– High Intensity Prismatic (HIP) comes with a 10 year warranty. HIP Type 4 meets all mandated FHWA retroreflectivity standards in all colors for ground mount signs.

Vulcan Ground Mount Signs

– Diamond Grade Cubed (DG3) provides superior performance and has a 12 year warranty.

– School signs and unsignalized pedestrian crosswalks shall be Fluorescent Yellow Green (FYG).

Fluroescent Yellow Green

With baby boomers aging, there has been a push for bigger, brighter signs on the road to serve this largest segment of the population. This push has accelerated the advancement of technology in sheeting research and development. Angularity and retroreflectivity are the key elements explored here. This can be defined by…

Retroreflectivity simply refers to the property of a traffic sign to reflect light back to the driver to increase nighttime visibility. Retroreflectiviity degrades over time, necessitating the need for systematic replacement of signs to maintain the retroreflectivity standards established and required by FHWA.

Angularity refers primarily to Entrance Angle, which is the angle of the sign relative to the vehicle when the sign is viewed by the driver. The angle at which a sign is seen affects its visibility, especially at night. The more angled a reflective sign is from the driver’s perspective, the lower the amount of retroreflected light reaching the driver and the less bright the sign appears. The Entrance Angle varies according to the driver’s distance from the sign, so the reflective sheeting must be able to perform well along the whole approach to the sign.

Vulcan Stop Signs

As seen in this photo, angularity greatly affects the visibility of a sign under nighttime conditions.

Alloy Substitution: What is the real difference between 5052 and 3000 series?

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Lately, the buzz in highway industry news has been centered on Alloy Substitution. 5052 alloy vs 3000 series alloys… what is the difference and why should you care?

At Vulcan, the highway industry is a major market that we manufacture sign blanks and finished signs for. 5052-H38 has been the highway industry standard alloy specified by all DOTs for over 40 years, and for good reason…


– Vulcan 5052 has 39.3% more Tensile strength and 33.3% more Yield strength than 3105*. This is critical to the performance of the sign in the field. A stronger sign resists vandalism along with providing greater wind load.

Vulcan Stop Sign Comparison Final

The lower Tensile strength found in 3105 also results in installation holes wearing out more quickly (as seen in the photo above on the left.) The 5052 alloy stop sign shown (in the photo above on the right) proves what a difference Tensile strength can make in the longevity of the sign.

– Vulcan 5052 has 5 times the magnesium content of 3105, giving it vastly superior corrosion resistance*

– Vulcan 5052 is manufactured using prime aluminum ingot, while it is common practice for 3000 series to be produced from scrap material

– Relative to the performance of the two alloys, the price difference is negligible

Vulcan Single Inventory Example

– Stocking only Vulcan 5052 alloy will simplify managing dual inventories, providing confidence that the alloy will stand up not only to DOT testing, but also harsh outdoor elements.

Vulcan specializes in the manufacture and fabrication of 5052-H38. Its long-standing reputation as the industry standard speaks for itself.

*Data from 2009 Aluminum Standards and Data issued by The Aluminum Association


The Blacksmith’s Hammer: Melting, Manufacturing, Stamping and Fabricating 5052 Aluminum Alloy


Hello! Welcome to The Blacksmith’s Hammer, a blog by Vulcan, Inc. Since 1935, Vulcan’s core products and services have been linked by a common thread… Aluminum. With five vertically integrated manufacturing facilities working together, each Vulcan division shares resources as well as knowledge, providing innovative fit-for-purpose products for a wide variety of markets.

Our blog, The Blacksmith’s Hammer, is intended to be an online extension of cutting edge aluminum manufacturing and fabrication information through metalworking. Our goal is to deliver insightful articles that stream live from our campus, providing in-depth knowledge of Vulcan, our capabilities and the markets we serve.

Our company and blog name say a lot about our commitment to the aluminum industry. Vulcan is symbolic of the metal industry, and is particularly appropriate for our company as melters, casters, rollers and fabricators of metal.

VULCAN: Roman and Greek God of fire and the forge; mythical inventor of smithing and metal working


This cast aluminum statue of Vulcan is located in the lobby of our corporate headquarters.

Below is a preview of a few of the topics that will be covered in this blog. We look forward to your comments and suggestions!

  • Alloy Substitution: What is the real difference between 5052 and 3000 Series?
  • Vinyl Sheeting 101: Everything you wanted to know and more
  • Custom Metal Stamping: An in-depth look at the process
  • 5754 Aluminum Alloy: The science behind 5754
  • Conversion Coating 101: 7 Steps to alodizing sign blanks
  • ANSI Safety Sign Redesign: What you need to know to comply

A longstanding reputation for quality products and competitive prices has placed Vulcan at the forefront of the various markets we serve. Our many years of experience in aluminum rolling and fabrication has broadened our marketing arena to include the manufacture of aluminum coil, aluminum blanks and sheet, traffic control signs, utility signs and markers, and custom metal stampings. For more information, please visit our website.