Adhesives in Stonework: Not All Glues Are Epoxy
By Frederick M. Hueston
All Glues Are Not Epoxy
Let’s clear something up that I hear way too often in this trade: not all glues are epoxy.
If you have been on a job site long enough, you have probably heard someone refer to every adhesive under the sun as “epoxy.”
It’s the same as calling every copier a “Xerox.” It might be common slang, but it is not correct, and it can cause real problems when you are trying to match the right product to the job.
Why Epoxy Became the Catch-All Term
Epoxy earned its reputation for strength, durability, and versatility, which is why it became the go-to for many stone jobs. Over time, the word “epoxy” turned into a lazy catch-all for any adhesive.
The problem is that in stone work, the wrong adhesive choice can mean the difference between a repair that lasts for decades and one that fails in months.
A Breakdown of Common Adhesives in Stonework
Here are the main adhesives you’ll encounter in stone restoration and fabrication work:
Epoxy
- What it is: Two-part adhesive made from resin and hardener
- Strengths: Very strong bond, excellent chemical resistance, long-term durability
- Best for: Structural repairs, high-stress bonding, attaching dissimilar materials
Polyester Resins
- What it is: Fast-curing adhesive used heavily in restoration work
- Strengths: Affordable, sets quickly, easy to sand and polish
- Best for: Filling chips and cracks, especially in marble and travertine
Vinyl Ester Resins
- What it is: A hybrid between polyester and epoxy
- Strengths: More chemical resistance and flexibility than polyester but not as strong as epoxy
- Best for: Outdoor or industrial work where chemical exposure is a concern
Cyanoacrylate (Super Glue)
- What it is: Quick-bonding adhesive for small-scale repairs
- Strengths: Instant set time, simple to use
- Best for: Temporary fixes, bonding small smooth surfaces
Polyurethane Adhesives
- What it is: Expanding adhesive that is highly water-resistant
- Strengths: Flexibility, good for porous materials
- Best for: Outdoor applications or situations where some expansion is useful
Why the Right Adhesive Matters
Choosing the wrong adhesive can mean:
- Weak joints
- Visible seams
- Repairs that fail completely
For example:
- Putting polyester in a high-stress structural repair that really needs epoxy won’t last.
- Using epoxy where polyester would have been enough may waste time, money, and create extra finishing work.
It’s not just about strength. Adhesives differ in curing methods, clarity, rigidity, expansion, and even whether they yellow over time. These details affect both the performance and appearance of the repair.
A Habit Worth Breaking
The next time you reach for adhesive, be specific. Instead of saying “Grab the epoxy,” say:
- “Get the polyester resin”
- “We need vinyl ester for this job.”
This avoids confusion and helps newer crew members learn which products are right for which situations.
Calling everything epoxy is a habit worth breaking. As a stone restoration pro, part of your skill is not only knowing how to restore stone, but also how to choose the right adhesive for the repair.
So next time someone asks for epoxy, stop and ask: “Is that really what we need?” That small question can save you from failed repairs, wasted time, and frustration later.
