Enamelling metals began as a way to enhance visual appeal while also protecting metal surfaces. Craftsmen fused glass coatings to metal, creating a durable barrier against corrosion with added vibrancy.
Even with major advancements such as the two-coat, one-firing (2C/1F) process, boric oxide B2O3 remains essential to high-quality enameled products.
Whether you’re producing cookware, industrial architectural panels, or consumer appliances, boric oxide helps control melt behavior, ensures adhesion, and prevents defects.
Why boric oxide matters in enameling
Compared to other materials used for vitreous enameled products, boric oxide stands out because it delivers benefits throughout the entire process.
During manufacturing, it reduces melt temperature, improves glass flow, optimizes energy efficiency, and increases productivity.
In finished products, it:
- Increases the adhesion strength
- Improves chemical durability
- Resists corrosion, preserving metal integrity
- Contributes to smoother, glossy surfaces
Using boric oxide extends the life of the underlying metal substrate, resulting in a better product overall.
Optimizing the enameling process
Boric oxide acts as a network modifier when it’s incorporated into enamel frits. It lowers viscosity and reduces surface tension, which makes the glaze fluid when molten and allows it to spread evenly over the metal substrate at a relatively low temperature. The good spreadability of enamel frit is fundamental to electrochemical reactions between frit and metal substrate—helping improve adhesion.
Read more about borates in enamels and glazes
Preventing enamel defects
Scrap and waste can be detrimental to your organization’s bottom line. The good news is that common defects are preventable by using boric oxide.
Common enamel defects include:
- Pinholing: Tiny surface holes caused by trapped gases
- Crazing: Fine surface cracks due to thermal mismatch
- Spalling: Flaking or chipping from poor adhesion
- Chemical degradation: Corrosion or color changes from insufficient chemical resistance
To prevent these issues, you need the right concentration of refined borates. Refinement not only removes impurities that disrupt the glass melt’s homogeneity but also ensures consistent boric oxide content for predictable melting. That can lower your energy consumption and subsequent emissions during production.
Large-scale enamel manufacturers
Scaling up the enameling process to manufacture larger products, such as architectural panels and signs, magnifies technical challenges. Matching the thermal expansion rates of glass and metal becomes harder due to a larger surface area. Even slight mismatches can cause enamels to crack during heating and cooling.
In large-scale environments where there is less margin for error, the use of refined borates in frits becomes essential.
Manufacturers may also opt for aluminum/silicon (ALUSI) coated steel as a preferred substrate for enameling large surfaces. With ALUSI-coated steel, an enamel can be applied in one coat, on one side, and fired only once, which lowers production costs while upholding rust resistant qualities.
Boron products for enameling
Both U.S. Borax products Neobor® (borax pentahydrate) and Dehybor® (anhydrous borax) are commonly used as high-quality boric oxide sources in enamel formulations.
Dehybor offers high B2O3 content and reliable performance as a concentrated powder. And, it is favored by those who are especially concerned with efficiency. Its anhydrous composition eliminates water of crystallization, minimizing furnace emissions, reducing corrosion risk, and allowing for faster melt rates as well as energy savings.
Our recent study with an end-user showed that substituting borax pentahydrate with Dehybor in enamel glaze production can improve the adhesiveness between iron substrate and glaze.
Beyond performance benefits, Dehybor’s higher bulk density can reduce shipping and handling costs.
More about Dehybor
Tailoring boric oxide for your process
Our technical experts can help you develop frit formulations customized to your equipment, product needs, and manufacturing goals.
For decades, our team has helped customers successfully integrate refined borates to improve both production efficiency and product quality.
Whether you’re scaling up your enameled products or troubleshooting defects, contact the U.S. Borax technical team.
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