All Glues Are Not Epoxy: A Common Misconception in Stone Work

Frederick M Hueston  StoneForensics.com

Let’s clear up a common misunderstanding in the stone-working world: not all glues are epoxy! If you’ve been on a job site long enough, you’ve probably heard someone casually refer to every adhesive under the sun as “epoxy.” While this shorthand might seem harmless, it’s like calling every copy machine a “Xerox”—technically incorrect and potentially misleading.

So, why does this matter? Understanding the differences between adhesives is critical for choosing the right product for the job. Let’s break it down.

Why Do We Call Everything Epoxy?

The term “epoxy” has become a catch-all because of epoxy’s reputation for strength and versatility. It’s the go-to adhesive for many stone applications, from bonding to repairs. Over time, the word has morphed into a generic term that’s often misapplied to other types of glues.

But just as you wouldn’t use a “Band-Aid” to refer to every kind of adhesive bandage, you shouldn’t lump all adhesives into the “epoxy” category.

The Reality: A World of Adhesives

There are several types of adhesives used in stone work, each with unique properties suited to specific tasks. Here’s a quick guide:

Epoxy

What It Is: A two-part adhesive consisting of resin and hardener.

Strengths: Exceptional bonding strength, chemical resistance, and durability.

Best For: Structural repairs, high-stress applications, and bonding dissimilar materials.

Polyester Resins

What It Is: A fast-curing adhesive commonly used in stone restoration.

Strengths: Affordable, quick-setting, and easy to sand or polish.

Best For: Filling chips and cracks, especially in marble and travertine.

Vinyl Ester Resins

What It Is: A hybrid between polyester and epoxy adhesives.

Strengths: Greater chemical resistance and flexibility than polyester but not as strong as epoxy.

Best For: Applications requiring chemical resistance, such as outdoor or industrial settings.

Cyanoacrylate (Super Glue)

What It Is: A fast-acting adhesive often used for small repairs.

Strengths: Quick drying, easy to use.

Best For: Temporary fixes and bonding small, smooth surfaces.

Polyurethane Adhesives

What It Is: A versatile adhesive that expands as it cures.

Strengths: Excellent water resistance and flexibility.

Best For: Outdoor applications or bonding porous materials.

Why the Right Glue Matters

Using the wrong adhesive can lead to weak bonds, discoloration, or even structural failure. For example, using polyester resin in a high-stress application where epoxy is needed could result in a repair that doesn’t hold. Conversely, using epoxy when polyester would suffice might waste time and money.

Selecting the right glue isn’t just about strength; it’s also about how the adhesive interacts with the stone. Will it cure clearly, or will it leave a visible seam? Will it expand or stay rigid? Each adhesive has its quirks, and knowing them can save you headaches down the road.

Breaking the Habit

To avoid confusion on your next project, start being specific about the type of adhesive you’re using. Instead of saying, “Grab the epoxy,” say, “Grab the polyester resin,” or “Let’s use the vinyl ester for this application.” Not only does this promote better communication, but it also helps newer team members learn the nuances of adhesive selection.

Referring to all glues as “epoxy” is a habit worth breaking. As a stone-working professional, your expertise lies in knowing the right tool for the job, and that includes adhesives. Whether you’re bonding, filling, or repairing, the adhesive you choose can make or break the project—literally.

So, the next time someone asks for epoxy, take a moment to ask, “Are we sure that’s what we need?” It’s a small change that can lead to stronger, longer-lasting results—and fewer misunderstandings on the job site.