How to Reduce Gypsum Board Weight with Boric Acid

:: Wednesday, May 24, 2023 :: Posted By Maryam Moravej

Supply chain bottlenecks are easing, yet shipping costs remain elevated compared to pre-pandemic levels. Higher rates are especially worrisome if you’re in the construction industry and regularly ship heavy materials such as gypsum wallboard.

What can you do to relieve stress on your bottom line and simultaneously enhance your products?

Invest in additives that support lighter products without sacrificing strength, safety, or quality. Using refined boric acid in gypsum board (drywall) slurry can help.

It’s hard to be light

The average gypsum wallboard sheet weighs just over 50 pounds, making it one of the heavier internal construction materials.

What’s responsible for its heft?

Wallboard is comprised of a network of needle-like gypsum crystals, which gives the board its physical strength—and its weight.

It seems paradoxical, but if you want to lower gypsum board weight then less gypsum is needed—from the paper/core interface to the edges and ends. Injecting foam during the slurry stage is a common way to lower density.

While this may create lighter boards, it increases the odds of adverse effects, such as over-drying that results in calcined gypsum.

Calcination weakens the bond between gypsum and the paper backing.

Over-drying can also create installation problems. If a board suffers damage in curing, it that may crumble when shipped or nailed at the construction site.

If you’re able to solve these issues, creating a lighter product can result in lower shipping costs while maintaining a high quality product.

How boric acid fortifies gypsum board

Loading boric acid into the slurry solves over-drying problems, namely because it raises gypsum’s calcination temperature.

As boric acid migrates to the board’s surface, it forms a thin, yet concentrated layer, that protects against over-drying and prevents calcination.

Boric acid also fortifies the board’s rigidity by transforming the structure of gypsum crystals, changing them from needle-like shapes into larger ones that cover more surface area. This change increases density and mechanical strength without impacting the board’s overall weight.

With these qualities, you can accelerate production—processing boards at higher temperatures with lower drying times. This not only saves energy but also reduces your carbon emission output.

Optibor TG: Go light without sacrificing strength

Optibor® TG is the right refined boric acid choice to produce lighter and stronger gypsum boards.

But how much boric acid do you need?

Your processing environment and gypsum quality dictate loading amount. On average, we recommend between 0.03 and 0.15% by weight. But, our technical experts can answer specific questions about incorporating borates in your particular process, including more information on proper loading.

Interested in learning more about our boric acid products? Contact the U.S. Borax technical team.




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U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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