If you are shopping for galvanized welded wire mesh for a fencing or construction project, you may have come across two similar‑sounding options: galvanized before welding and galvanized after welding. At first glance, they may look the same. But in reality, these two manufacturing processes produce very different products. One is more affordable, while the other offers superior durability. So, what is the difference between galvanized before welding and galvanized after welding?
What Is Galvanized Before Welding?
Galvanized before welding, often abbreviated as GBW, means the steel wires are first coated with zinc through a galvanizing process. After the wires are galvanized, they are then welded together to form the mesh panel. This process is simpler and faster, which makes it a more cost‑effective option.
What Is Galvanized After Welding?
Galvanized after welding, often abbreviated as GAW, means the mesh is welded first using plain black steel wire. Once the welding is complete, the entire mesh panel is dipped into a bath of molten zinc. This process is known as hot‑dip galvanizing. The result is a mesh panel that is fully coated with zinc on every surface, including the weld points.
The Critical Difference: The Weld Points
The most important difference between these two processes lies in the weld points. In GBW (galvanized before welding), the welding process burns off the zinc coating at each weld point. This leaves the weld points exposed and unprotected. In GAW (galvanized after welding), the zinc coating is applied after welding, so every weld point is fully covered with zinc. This is the key factor that determines the long‑term durability of the mesh.
Visual Comparison
Visually, both types of mesh may look similar when new. However, upon closer inspection, you may notice that GBW mesh often has dark or discolored spots at the weld points, where the zinc has burned away. GAW mesh, on the other hand, has a uniform, consistent coating across the entire panel, including the welds. This uniformity is a clear sign of higher quality.
Corrosion Resistance
Corrosion resistance is where these two products differ most significantly. In GBW mesh, the weld points are the weakest link. Rust will often start at the weld points and gradually spread across the panel. In GAW mesh, the complete zinc coverage provides uniform protection, and there is no weak point for rust to start. As a result, GAW mesh offers significantly better corrosion resistance, especially in humid or coastal environments.
Lifespan Comparison
The lifespan of GBW mesh in outdoor applications is typically 5 to 10 years, depending on the environment. The unprotected weld points will start to rust within a few years, and the mesh will eventually need replacement. GAW mesh, with its full zinc coverage, can last 20 to 30 years or more in outdoor conditions. This significantly longer lifespan makes GAW a better investment for long‑term projects.
Cost Comparison
GBW mesh is generally 20% to 40% cheaper than GAW mesh because the manufacturing process is simpler and requires less zinc. This lower price makes GBW attractive for budget‑conscious buyers. However, it is important to consider the total cost of ownership. While GBW costs less upfront, the need for earlier replacement and ongoing maintenance may make it more expensive over time.
Paragraph 9 – When to Choose Galvanized Before Welding (GBW)
GBW mesh is a suitable choice for certain applications where long‑term durability is not critical. Consider GBW if your project meets these conditions:
Indoor use where the mesh is not exposed to rain or moisture
Short‑term projects where the mesh is expected to last only a few years
Temporary fencing or enclosures
Budget‑constrained projects where cost is the primary factor
When to Choose Galvanized After Welding (GAW)
GAW mesh is the preferred choice for most outdoor and long‑term applications. Choose GAW if your project meets these conditions:
Outdoor fencing where the mesh is exposed to weather
Permanent structures that are expected to last 15‑20 years or more
Applications in humid or coastal areas with salt spray
Security fencing where strength and durability are critical
Projects where long‑term value is more important than initial cost
Common Misunderstanding
Some buyers mistakenly believe that all galvanized welded wire mesh is the same. They see the word “galvanized” and assume the product is fully protected against rust. However, if the mesh is galvanized before welding, the protection is not complete. The only way to ensure full protection is to choose galvanized after welding. Understanding this difference can save you from making a costly mistake.
How to Identify the Process
How can you tell which process was used? Here are a few practical tips:
Ask the supplier directly – The simplest and most reliable method. A reputable supplier will tell you clearly if the mesh is GBW or GAW.
Look at the weld points – GBW mesh often has dark or discolored spots at the welds. GAW mesh has a uniform, shiny coating across the entire panel.
Check the price – If the price seems too low for a heavy‑duty galvanized product, it is likely GBW.
Side‑by‑Side Comparison Table
Here is a quick summary of the key differences:
Feature GBW (Galvanized Before Welding) GAW (Galvanized After Welding)
Process Wire galvanized first, then welded Mesh welded first, then galvanized
Weld Point Protection Zinc burned off at welds Welds fully coated with zinc
Corrosion Resistance Moderate Excellent
Lifespan (outdoor) 5‑10 years 20‑30+ years
Cost Lower (20‑40% cheaper) Higher
Best For Indoor or temporary use Outdoor or permanent use
Real‑World Example
To help you understand the real‑world impact of this difference, consider this example: A buyer chooses GBW mesh for a farm fence in a tropical climate. Within three years, rust appears at the weld points. Within six years, the fence is weakened and needs to be replaced. A second buyer chooses GAW mesh for a similar farm. After 20 years, the fence is still strong and rust‑free. The initial cost of GAW was higher, but over two decades, the GAW fence proved to be the more economical choice.
Final Summary
So, what is the difference between galvanized before welding and galvanized after welding? The key difference is the protection of the weld points. In GBW, the zinc at the welds is burned off during welding, leaving them exposed to rust. In GAW, the entire mesh, including the welds, is fully coated with zinc after welding. This means GAW offers far better corrosion resistance and a much longer lifespan.
Final Advice
When choosing between GBW and GAW, consider the specific needs of your project. If your application is indoor or temporary and budget is the main concern, GBW may be a suitable choice. However, if your application is outdoor, long‑term, or in a challenging environment, GAW is the better investment. While GAW costs more upfront, its superior durability and lower maintenance requirements make it more cost‑effective over time. When in doubt, choose GAW for the best long‑term value.
Call to Action
Looking for high‑quality galvanized welded wire mesh for your project? Contact us today. We offer both GBW and GAW options with clear specifications and transparent pricing. Our team is ready to help you choose the right product for your specific needs.