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Epoxy Glue Explained – What It is and What You Can Use It For

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Written by: Jeremy Sanchez


Epoxy Glue Explained – What It is and What You Can Use It For

If you’re looking for great adhesives, you shouldn’t look further.

In this article, I’ll talk about epoxy glues and why they’re among the best types of glue out there.

Two-part epoxy glues, in particular, are especially good and strong. They’re very durable and resistant to many external hazards.

Epoxy adhesives are also versatile and hardy in time, allowing you to make long-term repairs on household objects and not only.

Professionals use two-part epoxy glues for small and large-scale projects with great success.

There’s no need to look further for excellent glues when epoxies are already here.

Keep reading for more information on epoxy glues!

Also, check out my comparison between epoxy and super glue.

Figurine fixed by epoxy glue

What is Epoxy Glue?

First, you should know that there are two types of epoxy glue – one-part and two-part epoxy glues.

The former is a type of epoxy that has already been mixed, while the former needs manual mixing before being used.

However, one-part epoxy glues are rare and worse overall than their two-part counterparts.

Two-part epoxy glues contain two components, the resin and the hardener. If you want the epoxy to begin curing, you’ll need to mix them in equal parts.

Once the resin and the hardener are put together, a heat-based chemical reaction begins the curing process.

Depending on the brand of two-part epoxies, the adhesives will contain various other compounds that influence how they act.

Specific compounds will decide the properties of epoxy and how efficiently it bonds to materials. In general, though, epoxy glues are both durable and extremely strong.

It’s also important to note that you can use epoxy glues for various applications, including small-time repairs, gap filling, and large-scale applications.

Epoxy glues will set quite quickly, though. You have about 10 minutes to position the material and work with the adhesive before it sets and hardens.

Two-part epoxy adhesives are very efficient, strong, and easy to use. Whereas one-part epoxy glues, not so much.

They need a higher curing temperature and don’t offer such a strong hold. Mixing the components yourself creates a more durable adhesive and a stronger hold on the materials.

Who Invented Epoxy Glue?

Paul Schlack is the discoverer of epoxy resin. In 1934 in Germany, he patented the formula for epoxy adhesive, a compound that used amines and epoxides to form a solid bond.

Nine years later, in 1943, Pierre Castan of Switzerland discovered another type of epoxy adhesive based on bisphenol-A.

Despite Paul Schlack being credited with the discovery and patent of epoxy glue, several contemporary scientists were researching the topic.

One of them, Dr. Sylvan Greenlee, had discovered a similar form of epoxy adhesive at that time.

Interestingly, the first forms of epoxy adhesive were used for dental fixtures.

Moreover, there exist over 50 substances that are collectively known as epoxy adhesives. Each of them has a different chemical construction.

How Does It Work?

Epoxy glues function based on the two components included in the mixture. The resin and the hardener come together, and a chemical reaction occurs between the two.

While there are over 50 combinations of resonance and hardeners, most behave this way. I’m not about to go into scientific details because that’s boring.

Suffice it to say that the resident (a monomeric resin) combines with the hardener (accelerator and plasticizer).

The hardener will cause the resident to harden into a form of solid plastic. There are a few differences based on the chemical composition of the two components.

Depending on that chemical makeup, the final bond could be more rigid or more flexible.

A heat-based chemical reaction ensues when the two components come together, and the epoxy hardens. This is the curing process, which we’ll go into down below!

How Does Epoxy Cure?

As I said earlier, the curing process begins when the two components, the resin, and the hardener, combine.

Thanks to the heat chemical reaction, the epoxy hardens and becomes plastic-solid.

At the molecular level, the chains making up the epoxy come together, forming a super-strong bond.

However, some two-part epoxies have thermoplastic polymers included in the mixture. This can further improve the solidity and hardness of the final bond.

As you might have noticed, the epoxy curing process is strongly related to heat. If it weren’t for the heat, the curing process wouldn’t happen.

This heating process is called an exothermal reaction, and it helps the resin cure faster. The bigger the reaction, the faster the glue hardens.

Interestingly enough, the thicker the layer of glue, the more heat is retained, and the chemical reaction is also bigger, which makes the epoxy cure faster.

You’ll have about 10 minutes to work with the adhesive before it hardens completely.

However, the complete curing process will take anywhere between 24 to 48 hours, depending on the surrounding heat and moisture.

What Is the Tensile Strength of Epoxy Glue?

Most experts agree that epoxy glue is one of the strongest adhesives in the industry. We could even say that epoxy is the most powerful glue, even among superglues.

However, this largely depends on the formula used to make the epoxy glues. Some brands use a weaker formula so that the glue will be weaker.

But, potentially, epoxy adhesive’s tensile strength caps at 6000PSI.

This means that one inch of epoxy glue can hold up to 6000pounds worth of weight or resist a total of 6000 pounds worth of force.

Moreover, a good epoxy adhesive is at the top of its game regarding:

  • Hardness
  • Structural integrity
  • Impact resistance
  • Weight-bearing capacity
  • Setting time
  • UV light resistance
  • Solvent resistance
  • Moisture resistance (100% waterproof)

With all these resistances, epoxy glue can bond almost any material in the worst environmental conditions.

The epoxy bond will stand strong and durable in a few years. This versatility and heightened resistance are why epoxies are so popular today.

What Can You Use Epoxy Glue For?

Epoxy glues are very versatile for the most part. They can be used for various applications and materials, including most porous and non-porous materials.

This is thanks to the multifaceted resistance to external hazards and durability to impact and shock.

Among the acceptable materials that epoxies can bond are metals, tiles, concrete, stone, plastics, ceramics, and wood.

However, epoxy glue isn’t particularly good for rubber, silicone, vinyl, parchment paper, or wax paper.

If the material is too smooth and even oily, the epoxy will not stick. Below, you’ll find a list of materials you can bond with perfectly:


Epoxy glues are most commonly used for applications involving wood. Even though professionals recommend wood glue as the best option for bonding wood, epoxy is a perfect replacement.

Wood glue is generally cheaper but less powerful than epoxy glue, either way.

So, if you want stronger glue, always go for epoxy glue. If you need a cheaper variant, then wood glue is also good.

In any case, epoxy is also good at filling gaps in the wood, thanks to its thickness. You can also repair rotten wood or wooden components using epoxy wood.


Epoxy can also be used on metal bonding. If you’ve recently broken a household appliance, you can easily repair it using epoxy.

Even if you need to piece something together made of metal, epoxy adhesives are the way to go! Let’s say that you need to seal an unpressurized pipe.

Then, I’d recommend using epoxy to do it!

The same applies when you need to screw bolts to metal or secure the bolts and harden the bond.

Epoxy glues are the next best thing after welding and soldering. But gluing things is easier than welding them, right?


Need to glue together car parts or lawn chairs made of plastic? Epoxy is your best friend for this!

Another great example is when you need to repair a burst PVC pipe in your bathroom. An epoxy adhesive can help you finish the repair in just a few minutes!


Did you know that epoxy can bond even cement? It can fill gaps in cement, more specifically.

But if you want to bond pieces of stone together, then epoxy is a great choice.

Moreover, if you need to repair or rebuild a concrete surface, then a two-part epoxy adhesive is your best choice.

Several popular brands of epoxy include J-B Weld, Gorilla, Loctite, Bob Smith Industries, and Dr. Crafty.

Cons of Epoxy Glue

Epoxy glues have several cons that you should know about. For instance, the short working time can be a con if you’re not good at bonding.

The working time isn’t favorable, and you’ll only have 10 minutes to reposition the materials.

If you don’t manage to position the materials during that time, you’ll be left with a faulty application.

However, the curing process can take up to two days once you bond the materials.

You’ll also need to clamp down the materials to help the epoxy cure in a reasonable time frame.

One more important disadvantage is that epoxy glue costs more than most other types of glue.

Moreover, you’ll need to add exact measures of resin and hardener during the mixing process. If you’re not precise, the adhesive won’t be as powerful.

How Do You Remove Epoxy Glue?

You know that epoxy glue is very strong and can harden to a super solid consistency. It’s also resistant to water, heat, and most solvents worldwide.

However, there has to be a way to remove it from a surface, right? Yes, there is, but I recommend you wear gloves when working with them because they can bond very easily to the skin.

If it gets on your skin, immediately wash with water because if it hardens, it’ll be impossible to remove without your skin attached.

Once it hardens, the only way to remove epoxy is by scraping it away. Now imagine scraping away the skin on your forearm because you were careless.

No solvents can remove epoxy adhesives easily. But if the glue hasn’t had time to cure, you can use isopropyl alcohol and acetone to remove it.

Apply with moderation and rub it over the epoxy. Then, remove it with a damp cloth!

Interesting Facts

This adhesive, too, has a few interesting points that I’d like to share with you. Chuckle away with these facts:

  • Epoxy will harden in 10 minutes, but it will fully cure in 2-3 days
  • The epoxy will cure even slower if you’re working in a cold environment. Hotter environments improve the curing time of the epoxy, but you’ll have a shorter working time if it’s hot.
  • If you need to apply two epoxy coatings, apply the second one within 48 hours after applying the first one. If you apply the second layer after the first one has cured, it won’t stick either.

That’s it for today!

Wrap Up

Epoxy is one of the strongest types of glue in the world. If the formula is good enough, epoxy is stronger than superglues.

It can bond most porous and non-porous materials, but its versatility isn’t its only selling point.

This adhesive is also easy to work with after you understand how the mixing process happens.

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