Duncan Galvanizing Blog

Why Do I Need Vent Holes?

Posted by Casey Shearns on Mon, May 10, 2021 @ 04:07 PM

If you’ve sent metal to be galvanized, Duncan or other galvanizers may have asked you to include specific vent holes in the piece. For successful batch hot-dip galvanizing, cleaning solutions and molten zinc must flow without undue resistance into, over, through, and out of the fabricated article. Our team broke down why these vent holes are necessary:

Safety of Personnel and Your Material

Without vent holes, the pressure built from the heat of the kettles can cause steel to explode in the zinc kettle, and seriously injure personnel, while destroying your material. For everyone’s safety in the plant, and for the safety of your material, we request adding vent holes to your steel before you send it for galvanizing.

Even Coating of Zinc

Vent holes also help the steel to be coated evenly throughout the inside and outside of the steel. Hot-dip galvanizing is the only process that protects both the inside and outside of tubular steel structures, and proper vent holes help this process to be effective. Lack of vent holes can cause the steel to have bare spots, uneven texture, and other zinc coating problems, so it’s important to ensure holes are placed properly so steel can be evenly coated. Even if the drain hole is only an inch away from its ideal location, that inch can create an air pocket, resulting in an uncoated area, which can result in rust staining even in the coated regions. An even coating of zinc helps with your steel’s corrosion protection and aesthetics and prevents unsightly zinc build up.

Complete Immersion

Appropriately placed and sized vent holes prevent the steel from floating in the zinc bath. Full immersion of the zinc is essential to the quality hot-dip galvanizing. The size and placement of these vent holes are different depending on the steel being galvanized, so check with the galvanizer where these holes are necessary to ensure the steel can be fully immersed in the zinc bath.

Contact Duncan Galvanizing

Duncan Galvanizing is proud to be the Northeast’s trusted provider of hot-dip galvanizing, Colorgalv (paint over galvanizing), and more. Give us a call today at 617-389 8440 or fill out a contact form on our website.

Tags: Hot Dip Galvanizing

Environmental Advantages of Hot Dip Galvanizing

Posted by Casey Shearns on Tue, Apr 20, 2021 @ 04:08 PM


Go Green wooden sign with a forest background

One of the benefits of hot-dip galvanizing is that it is a very ‘green’ product. If your project is looking to lessen its environmental impacts by reducing waste, harmful emissions, and other adverse environmental effects, hot-dip galvanizing is a great corrosion protection option. Here are a few of the environmental benefits of hot-dip galvanizing:

Recyclable & Infinitely Renewable

Zinc and steel are both recyclable, meaning even at the end-of-life of a structure or product, the zinc can be reused for other purposes, reducing the amount of waste hot-dip galvanizing produces. In fact, 30% of the world’s zinc has been recycled, and steel is the most recycled resource in the world. Therefore, at the end of your project’s life, the galvanized steel can almost always be recycled and reused. This dramatically decreases the amount of waste that your project will produce.

Additionally, zinc is an infinitely renewable resource. Zinc can be recycled without losing any of its critical chemical or physical properties. Both zinc and steel can be reused many times without losing their structural integrity. However, the longevity of hot-dip galvanized steel allows for the product to have a long life before it ever needs to be recycled.

Zinc is Natural and Abundant

Zinc, which composes about 98% of hot-dip galvanizing, is a resource that can be found naturally in many elements of the earth, including water, soil, and even the earth’s crust. Zinc is also essential to life on earth, and is a necessary mineral for almost every organism on earth to live. Because zinc is already abundant in the environment naturally, the use of hot-dip galvanizing does not introduce disruptive or harmful elements into the environment like other corrosion protection methods.

Life Cycle Cost Assessment & Additional Benefits

A products’ life-cycle cost assessment is a measurement of its impact on the environment throughout its entire life, from production to end-of-life. The LCA conducted using a wide variety of data over time for hot-dip galvanized steel found many additional environmental benefits. For example, all material inputs and emissions outputs are isolated to the production phase, most hot-dip galvanized structures require little to no maintenance throughout the project's life, and it does not use any additional materials after the initial production and installation.

The official life cycle cost assessment of hot-dip galvanized steel can be found here.

Contact Duncan Galvanizing

Duncan Galvanizing is the Northeast’s trusted provider of hot-dip galvanized steel, color galvanizing (factory-applied painting or powder coating over galvanized steel), and more. Contact us today at (617) 389-8440 or fill out an online contact form and we will reach out to you.

Why Specify Duplex Coatings?

Posted by Casey Shearns on Fri, Apr 09, 2021 @ 10:45 AM


Screen Shot 2021-04-01 at 3.13.14 PM

Duplex coatings are a great way to add reliable and long-lasting corrosion protection to your steel, as well as improve its aesthetics. We broke down the facts about duplex coatings, and a few reasons to specify Duncan’s duplex coating system on your next project:

What is a Duplex Coating System?

A duplex coating system is the use of two coating systems - hot dip galvanizing and either a liquid or powder coating over the galvanized steel. The combination of these two processes  provide excellent protection against corrosion, and far better protection than using just one alone. This allows for less maintenance over time, a more polished appearance, and other benefits.

Benefits of Duplex Coating

  • Synergistic Effect

Duplex coatings provide enhanced protection for steel. When hot-dip galvanized steel is topcoated with paint or powder, this duplex system provides a more enhanced level of corrosion protection known as the synergistic effect. Paint or powder coating provides a protective barrier for hot dip galvanizing, as the exterior layer slows down corrosion from reaching the underlying zinc. If the exterior layer is worn down, the zinc from the hot dip galvanizing still provides excellent corrosion protection. This combined system is more than the sum of their parts. Both parts extend life of each other, they do much better and last much longer than if they were isolated. Additionally, the hot dip galvanizing primer virtually eliminates underfilm corrosion and paint peeling. It also extends the maintenance cycle of black steel by up to 2x. Duncan Duplex Coating Systems offer a 20 year warranty against corrosion, so your project will be protected against corrosion for decades to come.

  • Aesthetics

Duplex coatings  are also great for the aesthetics of your projects. Sometimes, the silver finish of hot dip galvanizing alone is not appropriate for certain projects. Duplex Coatings allow for a number of different finishes on steel to achieve your desired appearance. Duncan’s Colorgalv allows steel to be finished with a wide variety of colors. Some projects may require a vibrant color for safety reasons, need to blend in with surroundings, or other have other specific aesthetic needs. Duplex coatings  use paint or powder to make this possible.

  • Economic Benefits

There are also economic benefits when duplex coatings are specified. When a duplex coating is used, galvanized steel will often stay in good shape for decades until maintenance is needed. The less maintenance required, the less money that needs to be spent on the project after completion. Because of the synergistic effect dramatically increasing the time before maintenance, the initial cost pays off over the life of the project and ends up costing far less than coating bare steel.



Did you know that Duncan Galvanizing was the first galvanizer in the country to do Hot Dip Galvanizing and factory applied coatings when it introduced Colorgalv in the mid-1970’s?

Contact Duncan Galvanizing

For high-quality duplex coating systems, hot dip galvanizing, color galvanizing, and more, Contact Duncan Galvanizing at (617) 389-8440 or fill out an online form to get started.

Tags: Colorgalv, Hot Dip Galvanizing

The Importance of Galvanizing Steel

Posted by Casey Shearns on Fri, Mar 26, 2021 @ 03:32 PM



Utilizing a protective coating such as hot-dip galvanizing is incredibly important to protect steel against damage from corrosion and other sources. Damage to steel can cause impactful financial, aesthetic, and safety failures, so it’s crucial to specify a protective coating such as hot dip galvanizing if steel is being used. Important benefits of galvanizing include:  

Prevents Structural Failures

Structural failures due to corroded steel can be devastating. They can cause serious injuries, loss of life, public outcry, and overwhelming financial damage. Hot dip galvanizing offers outstanding steel corrosion protection that preserves the structural integrity and can help to ensure your steel stays safe for use for years to come. The tightly-bonded, abrasion resistant inter metallic layers provide an unmatched protection from corrosion.

Prevents Aesthetic Failures

Aesthetic failures, although not physically dangerous, can be damaging to the reputation of your business. A project with damage and corrosion can distract from the work put in and the beauty of the architecture, and send the wrong message about the quality of your work. Hot dip galvanizing is a fantastic way to keep your steel looking like-new, decades after project completion. It’s important to use a protective coating that will uphold the desired look of the steel used to prevent any unsightly corrosion, and lost opportunities for future work. Additionally, hot dip galvanizing is able to protect the aesthetics of even the most intricate of steel designs, and can even be used on artistic projects to preserve its original finish.

Saves Time & Money from Corrosion Costs

Corrosion can result in pricey and time-consuming maintenance. In fact, 659 billion dollars of structural damage have occurred in the US alone from corrosion, and can quickly create a financial burden for you. Galvanizing allows for years, sometimes decades before maintenance is required. This extended time without maintenance allows for significant life-cycle cost savings. Oftentimes, the initial cost is the life cycle cost, making galvanizing a great investment.

Additionally, the additional resources needed for extra maintenance can derail your environmental sustainability efforts. Quality protective coating can eliminate the need for the use of excess natural resources due to the need for constant maintenance.

Protection From Vandalism

Vandalism and graffiti can be costly if it cannot be easily removed from steel. Some finishes offer graffiti protection to ensure that your investment will not be permanently damaged by vandalism. This is particularly important to consider if you are building a structure in a high traffic area, such as public transportation. A finish with graffiti protection may be a good choice if your team is concerned about vandalism. If you utilize one of Duncan Colorgalv Plus coatings, you will have long lasting anti-graffiti protection.

Contact Duncan Galvanizing - Hot Dip Galvanizing in Everett, MA

Duncan Galvanizing is the Northeast’s trusted provider of hot-dip galvanizing (Duragalv), color galvanizing (Colorgalv) and more. Contact us today at (617) 389-8440 to get started or request a quote.

Tags: Corrosion Protection

Why Specify Galvanizing?

Posted by Casey Shearns on Tue, Mar 09, 2021 @ 04:46 PM


Steel corrosion can be costly, dangerous, and unsightly.  It’s important to make sure the steel used in your project is utilizing an effective method for protection against corrosion, abrasion, and weather conditions. Hot dip galvanizing is the process of factory dipping of fabricated steel into a kettle of molten zinc with the goal of preventing this corrosion, and creating a steel product that stays structurally sound and aesthetically pleasing for years to come. Hot dip galvanizing is often the preferred method of corrosion protection for steel for a number of its unique benefits, including:

Durability & Corrosion Protection

First, hot dip galvanizing is a great investment because of its durability and protection from even the harshest environments. This protective zinc alloy becomes tightly bonded to the steel, creating a layered protection with a bond strength of around 3,600 psi. In addition to the corrosion protection in any environment, this alloy also provides excellent abrasion resistance that is harder than the steel, protecting it from any damage that might occur during the shipment or construction process. 

Additionally, hot dip galvanizing is the ONLY system that protects the steel on the inside and the outside. Ensuring that the inside of fabricated steel is galvanized can be crucial to the integrity and life of the steel.  Also, because the steel is completely submerged in our zinc bath, there is a uniform protection on the entirety of the fabricated steel, while other methods such as liquid coatings often cause the protective coating along the edges to be thinner. Utilizing hot dip galvanizing is the only process that ensures this complete and uniform protection for steel.


Hot dip galvanizing also has several cost benefits. The overall material and application generally costs less than other corrosion protection methods. It also can be completed in less time due to the factory immersion process, saving construction time costs as well.

It also has lifetime cost benefits, as hot dip galvanized steel requires much less maintenance over time. In this chart, you can see the impressive amount of time hot dip galvanizing protects the steel from corrosion before first maintenance is required. 



Both zinc and steel are 100% recyclable, making hot dip galvanizing a very ‘green’ process. Zinc is natural, abundant, and essential to life. Therefore, the use of steel is not introducing any harmful substances into the environment. Zinc and steel can also be recycled to be used many times over in different projects, so even at the end of a building or structure’s life, that material can be used again. In fact, 30% of the world’s zinc supply is recycled. This way, you can ensure that the materials used will not create waste. Hot dip galvanizing also uses less natural resources and creates less harmful emissions into the atmosphere, contributing to the overall environmental friendliness of your construction job.

Availability & Versatility

Hot dip galvanized steel is both readily available and accessible, as well as versatile for a variety of projects. Steel of many different shapes and sizes can be galvanized. Because of the total immersion in the zinc bath, even intricate shapes can be fully galvanized and protected from corrosion. This makes hot dip galvanizing a great choice for steel components that have a unique or complicated shape.

Additionally, because galvanizing occurs factory in a controlled environment, the process can be completed in any weather conditions, while other processes can’t. This allows construction projects to move quicker when the galvanizing can be completed any day, any time of year. The average turnaround time for hot dip galvanized steel ready for use is about 3-5 days, quicker than many other processes.

Contact Duncan Galvanizing

Duncan Galvanizing is the Northeast’s trusted provider of hot dip galvanizing, color galvanizing, and more. Contact Howie Levine for help with specifications or Seth Dubinsky to request a quote at (617) 389-8440 or fill out an online form to get started. 

Tags: Corrosion Protection, Hot Dip Galvanizing, Duncan Galvanizing


Posted by Howard Levine on Thu, Jul 19, 2018 @ 09:41 AM


specification image


In order to provide a level of quality in a project's construction documents, there are four different approaches to specifications that an architect or designer can choose from:


A closed proprietary specification that describes a product, process, or manufacturer by name. It is used when the design professional has determined that what is being specified is the best choice for the project and that no substitution is permitted.


A prescriptive specification where products are identified by listing the manufacturer's name, process or product name, and a description of product composition. It sets the "level of quality bar" yet allows others to submit if they meet the specified criteria.


A specification that defines the desired functional outcome. It contains performance criteria required for products, processes, or methods in the contract document. This method does not describe the design characteristics and manufacturing methodology found in the Basis of Design specification.


An open proprietary specification that lists the product, process, or manufacturer(s) followed by the term "or equal". It does not limit to specific supplier or product.

 What is an "equal"?

The Encarta Dictionary defines equal as "identical in size, quantity, value, or standard".

This definition is particularly important to those in the A/E/C community charged with determining what products, processes, or methods are used in construction projects.

 When the "or equal" spec is used, any manufacturer is free to submit their product, process or method in the belief that it is equal to what is specified or hope that the decision maker will be too busy to take the time to research the submittal and it will be accepted. A good example of this is the comparison of a process or product with the "or equal" spec.

 Here are just a few of the issues to be considered when reviewing an "or equal" submittal:

                 • Will the product or process meet ALL the criteria set forth in the specification?
                 • Are environmentally appropriate materials used?
                 • Will it help attain LEED certification?
                 • Does it offer the same warranty as that which was specified?
                 • Will the manufacturer or processor take sole source responsibility if there is a failure?

The bottom line is:



Contact Duncan Galvanizing

Duncan Galvanizing is proud to be the Northeast's premier hot dip galvanizer. Give us a call today at 617-389-8440.


Tags: Duncan Galvanizing, Engineering Topics


Posted by Howard Levine on Fri, Jun 19, 2015 @ 03:29 PM

Rusty Rooftop Dunnage

The expression “out of sight, out of mind” is particularly appropriate for rooftop dunnage. Rarely, if ever, is any attention paid to the steel supporting the mechanical equipment supports, HVAC, solar and cooling tower.

Even though this material doesn’t have the same cachet as Architecturally Exposed Structural Steel, it is an integral part of the building. While initial cost of the dunnage is part of the overall construction budget, replacement or maintenance is not. That cost comes directly out of the Owner’s pocket!

How to Protect Steel From Corrosion

How can the steel be protected from corrosion in the aggressive New England environment? The answer is simple: Hot Dip Galvanizing. Galvanizing is a metallurgical bond between the zinc and steel that provides protection against virtually any corrosion causing element. 

Hot Dip Galvanizing lasts longer and protects better than paint and is a “green” process and will help in reaching your LEED goals. Paint is NOT enough to protect your rooftop steel.

Think about it: You don’t want to rent a crane in five years to repair a problem caused today.

Contact Duncan Galvanizing Today

Duncan Galvanizing is proud to be the Northeast's premier hot dip galvanizers. Contact us today at 617-389-8440.

HOT TOPICS IN HOT DIP GALVANIZING: Galvanizing Slip Factor, Hydrogen Embrittlement & A-490 Bolts

Posted by Howard Levine on Fri, May 29, 2015 @ 03:42 PM

Galvanizing Bolts

In 1837, Stanislaus Sorel received a patent for galvanizing. Even though the process has been around for over 175 years, it’s not your great, great, great grandfather’s galvanizing!

Of course, many of the same principles still apply…outstanding corrosion protection, metallurgical bonding,100% surface protection of the interior and exterior of steel fabrications, but the galvanizing industry has adapted to the demands of the 21st century by recognizing that there is more to it than stopping rust. This article will highlight some of the technical trends in galvanizing benefitting the engineering community.

There are several issues currently being addressed by the industry with the charge being lead by the American Galvanizers Association.  Of particular note and impact on the engineering community are Slip Factors for Slip Critical Connections and Hydrogen Embrittlement /Galvanizing  A-490 Bolts.

A slip factor study by the American Galvanizers Association is in the final stages of research. The goal of the study is a guideline or specification with instructions on preparing a galvanized surface to achieve a Class B slip coefficient. With a higher slip coefficient, designers will be able to use galvanized steel in applications previously not considered or decrease costs by using less connections. Previous phases of testing indicate that obtaining the required 0.50 slip coefficient through roughening or other treatments is not possible. Therefore, the testing is focused on the use of a zinc-rich paint over the galvanized surface to obtain the Class B slip coefficient. The final phase of testing is slated to occur early this year.

Hydrogen Embrittlement Study

Another study deals with the feasibility of hot-dip galvanizing A490 bolts without a danger of hydrogen embrittlement. Hydrogen embrittlement originates in the cleaning step of the hot-dip galvanizing process. During the process, the heating of the steel causes some of the atomic hydrogen absorbed from the pickling acid to migrate into “trap sites” within the steel matrix. Once in the trap site, the hydrogen atoms can cause a premature failure of the steel fastener when installed in the field. Removing the source of hydrogen atoms (pickling acids) from the galvanizing process essentially eliminates the concern for hydrogen embrittlement failure. To accomplish this, the time the steel spends immersed in the pickling acids must be eliminated as this is the only source of hydrogen atoms in the process.  Mechanical surface preparation (blasting or wheel abrading) of the steel after the degreasing stage will solve the problem. The study tested several bolts galvanized with this modified process for compliance with ASTM and other standards. Results of these tests were typical for hot-dip galvanizing, showed no adverse effect on the coating from the modified process, and met the requirements of ASTM A153. The A490 bolt study has been completed and is being introduced to ASTM for inclusion in the specification. There may be further testing to explore other steel base materials to prove there is no difference in their hydrogen threshold after galvanizing.  More tests will be done in 2015 and the total report will be published and a change will be proposed to the new specification on high strength bolts. It should be noted that these practices have been utilized in Europe for many years and the use of hot-dip galvanized A490 bolts is an accepted practice in design and construction.

Why is this Important?

Educating the next generation of architects and engineers is a priority. Many have little or no knowledge of the galvanizing process. Their college curriculum skims over (or ignores) the need for corrosion protection. Visits to college campuses and A/E/C offices across the United States and Canada are being held to educate future architects and engineers about hot-dip galvanized steel. Through these presentations, students and “emerging professionals” will learn about the galvanizing process, design, sustainability, performance, specification, cost, and inspection.

Contact Duncan Galvanizing

If you or your office would be interested in a presentation, click here. For more info, give us a call at 617-389-8440.

Tags: Hot Dip Galvanizing, Engineering Topics

Do You Want This?

Posted by Howard Levine on Tue, Sep 30, 2014 @ 03:07 PM

Colorgalv by Duncan

Or This?

NOT Colorgalv!

Rainbow Terrace Apartments in Salem, MA
Click each image for an enlarged view.

A Long-Lasting Coating SystemThat Looks Good Too

Duncan Colorgalv Thermoset 10

  • Anti-Graffiti Coating Available

  • No Maintenance Required

  • 20 Year Warrantee

  • Meets All "Green" Standards

What Our Customers Say

"I specified Duncan Colorgalv Thermoset 10 for Rainbow Terrace Apartments in Salem and Willowood Gardens in Gloucester because I wanted my clients to have a long-lasting, durable coating system for their exposed steel."

"Having done design work for many of the region's Housing Authorities, I was aware of the need for a maintenance-free product to control operational costs. Duncan Colorgalv Thermoset 10 was my choice!"

~~ Robert Mitnik, A/A

Would you like more information? Call Duncan at 617-389-8440 or email info@duncangalvanizing.com.


Tags: Colorgalv Thermoset

Spotlight On Colorgalv

Posted by Howard Levine on Tue, Sep 30, 2014 @ 02:45 PM

Colorgalv by Duncan

Click each image for an enlarged view.

NOT Colorgalv!

Riverfront Fencing Hartford Connecticut

Colorgalv®. There is NO equal.
And this proves it!

The picture on the top was taken in December of 2003, almost 10 years after the fencing was installed. It still looks great!

The picture on the bottom, also taken in December of 2003, has only been installed since 1999, and it has failed completely.

The only similarities between these two installations is the location. They are adjacent to each other on the Connecticut River.

Why would one fail and the other look as good as new 10 years later? The answer is simple: The installation on the top was Colorgalv® by Duncan. The one on the bottom was an “or equal”. Even though Colorgalv® was specified for the fencing on the bottom, the contractor submitted an “or equal”.

Why accept a substitution?
Is it cheaper? No. Is it better? No. Will it last longer? No.

The initial cost of Colorgalv® is virtually equal to painting over galvanizing, so there really is no appreciable “first cost” savings by going with an “or equal”. And when you look at life cycle costing, well, the savings are astronomical.

Colorgalv® is a complete process. All work is done in one factory controlled environment. Nothing is left to chance and all the variables that could possibly lead to a failure have been eliminated. So, Colorgalv® is truly a better process than an “or equal”.

And, since Colorgalv® is warranteed for 20 years, you will have the peace of mind knowing that a company in business since 1890 will be standing behind the work to ensure the longevity of the installation.

Contact Duncan Galvanizing

Want more information? Call Duncan at 617-389-8440 or email info@duncangalvanizing.com.

Tags: Corrosion Protection, Colorgalv