Wood Glue vs Epoxy: Which is Better? (2023 Guide)
Wood glue and epoxy are two of the most commonly used adhesives in the woodworking and DIY world – and for good reason. They’re strong, versatile, and can last for years.
But there are a few differences you should know about.
In this wood glue vs epoxy comparison, I’ll explain everything you should know about these adhesives and when to use each one. Let’s dig in!
Wood glue is more affordable, easier to use, and more versatile than an epoxy glue, but epoxies are stronger, more durable, and longer lasting. Most wood glues cure quickly, whereas epoxies can take days to cure completely.
In This Article:
What Is Wood Glue?
Wood glue, otherwise known as polyvinyl acetate (PVA), is an inexpensive, non-toxic, and efficient adhesive that’s used for a variety of woodworking projects.
The types of wood glue on the market today usually contain the following:
- A polyvinyl acetate homopolymer
- A polyvinyl acetate copolymer
- A polyvinyl alcohol solution
- Some kind of defoamer
- A plasticizing agent
- Some kind of preservative
Different Kinds of Wood Glue
In addition to polyvinyl acetate, polyurethane glue, cyanoacrylates, and animal/hide glue can be used as wood glues. Here’s how these wood glues are different:
Polyvinyl Acetate (PVA)
This kind of wood glue is affordable and easy to find; it’s sold at all big-box hardware stores and online. It comes in the brand names Elmer’s and Titebond.
Plus, it doesn’t discolor like other glues, and its flexibility helps it say strong for many years.
And when you use PVA, you don’t have to worry about toxic fumes being emitted.
Worried about the drying color of your wood glue? Check out my guide on what color wood glues dry for more info!
Gorilla glue is not water-based, so when you apply it you don’t have to worry about the glue getting into the wood pores and swelling the wood as it cures.
It create a strong bond that can last for years on many different surfaces.
Also, this kind of glue can be used to fix finished wood pieces together since it doesn’t need to soak into wood pores to be a strong adhesive.
And since moisture facilitates the chemical reaction that is the curing process, polyurethane glue is a good glue to use with oily woods and woods that contain a lot of moisture.
PVA glue, on the other hand, is not good for such woods because it mixes with the oil or moisture, which prevents it from being a strong adhesive.
These adhesives aren’t the strongest, but they’re sought-after because they’re quick-drying and clear. Also known as Super Glue or Crazy Glue, they’re slightly more expensive than PVA and polyurethane glue, and they’re often used on furniture and trim because of these properties.
This adhesive is 3,000 years old, dating back to ancient Egypt. Before PVA, this was the glue most woodworkers used for their projects. Today it’s used on instruments and furniture.
It goes well with a wide variety of stains and finishes, and it shrinks as it dries.
And it’s not a permanent glue, so it can be easily removed.
Plus, sanding it won’t clog your sandpaper.
Check out my hide glue vs wood glue comparison for more info!
What Is Epoxy Glue?
The term “epoxy” refers to any adhesive, plastic, or other material that’s a polymer containing epoxide.
Otherwise known as polyepoxides or epoxy resins, epoxies are used to make scratch-resistant fillers, protective coatings, and adhesives.
Epoxies are viscous before curing, and usually it takes seven days to get completely cured epoxy.
As far as epoxy adhesives are concerned, these bond well to a range of substrates, including metal, glass, concrete, wood, and stone.
When epoxy resin is mixed with a chemical hardener and applied to a surface, it’ll eventually cure into a hardened plastic.
Different Kinds of Epoxy
Epoxy Novolac Adhesives
Epoxy novolac adhesives are chemical-resistant and also able to withstand high temperatures. They’re stronger than DGEBA epoxies, mainly because of how they’re cured.
To ensure strength, these adhesives must cure in a high-temperature environment; if they cure at room temperature they won’t be stronger than DGEBA epoxies.
There are versions that cure quicker, and these don’t require high-temperature curing. But with these, quick curing comes at the cost of strength.
Diglycidyl Ether of Bisphenol A (DGEBA)
This is the oldest kind of epoxy resin, and it’s more affordable than other versions, mainly because it’s made with inexpensive components.
A DGEBA epoxy that cures at room temperature can be used with a range of catalysts to achieve different properties.
Some DGEBA epoxies have a low molecular weight whereas others have a higher molecular weight. There are also brominated DGEBA epoxy resins, and these are mainly used when heat resistance is essential.
Difference Between Wood Glue vs Epoxy
Generally speaking, epoxies are stronger than most of the adhesives that are used as wood glues. So wood pieces that are fixed together with an epoxy resin will stay bound longer than wood pieces that are fixed together with wood glue.
But some wood glues are stronger than some epoxies, like in the case of Gorilla polyurethane wood glue vs DGEBA epoxy resin.
Epoxies get their strength from their compositions, and their strength makes them great for bonding metals, glass, stone, tile, and other materials together.
But once epoxy resin has had ample time to cure, it will be pretty hard to break down and remove without damaging the material. Therefore, you should only use this adhesive if you don’t intend to dissolve the bond it forms later on.
Epoxies are also more durable, which means they can withstand heat, chemicals, and moisture better than most wood glues. This is why many outdoor structures utilize epoxy in some way.
Prolonged exposure to the elements won’t break down epoxies, whereas it could break down wood glue in a short period of time.
That said, the durability of epoxy is in large part determined by the hardener it’s mixed with
The material epoxy is used on also plays a role in determining its durability. For example, if epoxy is applied to a wood surface that has many pores, it won’t be able to form the strongest bond, as the pores will prevent this.
But the bonds epoxy can form with metals and other non-porous materials are much stronger because these materials lack pores.
And just as the strength of epoxy comes from its composition, so does its durability.
Epoxy adhesives are generally more water-resistant than wood glues, with the exception being Gorilla polyurethane wood glue.
If this wood glue is applied properly, it can form a moisture-resistant bond that’s almost waterproof. The glue’s composition is what makes this possible.
This property is what makes this wood glue great for marine applications, like docks, boats, and offshore structures.
The one thing you need to know before using polyurethane glue is that it expands as it cures, which means if it’s applied to porous wood it could expand and even fracture the material.
And this is another adhesive that’s difficult to remove once it’s started curing.
A lot of homeowners use this kind of wood glue on their doors and windows to form water-proof seals.
Most epoxies are more expensive than wood glues, and that’s mainly because more components are used to make epoxies. Plus, these components are generally more expensive than the components used to make wood glues.
That said, some wood glues are more expensive than some epoxies. For example, some quick-drying, clear wood glues are more expensive than some low-grade epoxies because of the properties they boast.
To be more specific, a liter of wood glue will run you about $40, whereas a liter of epoxy resin (that has the hardener already mixed in) may run you $80.
And if you use a top brand like Gorilla, expect to pay a little more just for the name.
Epoxies take longer to cure, and even those that are “quick-drying” take longer to cure than most wood glues. Again, composition in large part determines how much time is needed for curing.
And remember that curing time and strength go hand in hand. Specifically, the longer it takes an adhesive to cure, the stronger it’ll be.
Advantages of Wood Glue
Wood glues are great for gluing wood and wood-based materials, and they’re also more affordable than epoxies. PVA glues can cost under $6 or $7, while an epoxy glue can run $8 or more.
Plus, there’s a wider variety of wood glues, and many woodworkers insist these look better with paints and stains.
Wood Bonding Alternative
Often, wood glue can be used instead of nails or screws, and it can also be used with either fastener to ensure a stronger bond.
Looking for the best wood glues? Check out the best wood glues for cabinets!
Wood glue can be dissolved and removed easily, whereas removing epoxy is difficult and often results in damaged materials.
Advantages of Epoxy
Epoxies are great when you need an adhesive that’ll form a strong bond. Not only can they withstand a lot of pressure, but they’re also resistant to moisture, heat, chemicals, etc. And because they’re strong and durable, they’re long-lasting and therefore cost-effective too.
Sealing a joint gap with epoxy is a great way to eliminate the gaps. It’s much harder to do this with wood glues. That said, you should be careful when using epoxy in this way, as too much could cause a buildup that’s hard to remove.
Clamps Are Unnecessary
Often clamps are used to speed up the wood glue drying process, but these aren’t needed when you use epoxies, and this is because epoxies are strong enough to form a strong bond without the assistance of clamps.
Is wood glue stronger than epoxy?
Generally speaking, wood glues are not stronger than epoxies. That said, a high-end wood glue, like Gorilla polyurethane glue, is stronger than a low-grade DGEBA epoxy.
Can epoxy be used as wood glue?
Yes, epoxies can be used as wood glue. Often they’re used for this purpose, as they’re strong, durable, easy to apply, and long-lasting. An epoxy glue can join many different materials and surfaces, which makes them a convenient adhesive to have.
So who’s the real winner in the contest of epoxy vs wood glue? Well, epoxies are generally stronger than wood glues, and therefore more durable and longer lasting.
But wood glues are more affordable, they’re easy to apply, and there are different kinds for different purposes.
In the end, you can’t go wrong with either wood glue or epoxy when working on your woodworking project. Both types of glue create strong bonds that can last for years when applied properly.