Choosing the Right Glue: Understanding Different Types of Wood Glue
Tackling repairs or a woodworking project where you need to join together wood pieces? You don’t always need screws or nails for this. In some cases, the right wood glue can do the job! But which type works best for your project?
Different types of wood glue for furniture or other woodworking projects are available. With several options to consider, knowing which to pick isn’t always easy. We’ll go over different kinds — and give you helpful tips on choosing the right one!
Types of Wood Glue
Why are there multiple kinds? Woodworking projects vary in terms of types of wood used, how strong an adhesive needs to be, and other factors. Different kinds of glue offer different properties and variations to meet these needs, such as:
- Strength
- Viscosity or thickness
- Cure time
- Drying time
Let’s explore the different types of wood glue available for woodworking.
Cyanoacrylate Glue (CA)
Have you ever worked with superglue? That’s what this fast-drying acrylic resin is! When you need instant bond, this is usually the best choice of glue. CA has a speedy curing and drying time compared to most other wood adhesives. You can use it to make quick repairs. Or you can use it for making the edges of MDF or other templates harder.
But there’s a catch — CA isn’t designed for permanent use. It’s a good choice for temporary connections. For example, let’s say you’re using something more durable and long-lasting, like polyvinyl acetate (PVA), on wood pieces. You can use CA to temporarily hold these pieces together while the PVA dries.
Properties of CA include the following:
- Instantly bonds
- Rapid open and clamp time of a minute or less
- Simple cleanup using acetone
Epoxy
Looking for wood glue to fill in knot holes or cracks in wood pieces? Epoxy is typically the right choice for this purpose. It’s a waterproof two-part glue that requires mixing, but offers a stronger bond than many other glues. Thinner epoxy is suitable for repairing wood. Thicker epoxy is better for larger projects, like building a boat.
Some epoxies dry in as little as five minutes, so working time is limited. However, like most adhesives, the longer it takes to dry, the stronger the bond it forms. It’s a good option for marine woodworking and other outdoor projects.
Epoxy’s properties include:
- Short set time
- Adjustable viscosity or thickness, depending on the thickeners you use
- Cleanup using acetone
Hide Glue
Did you know that hide glue is the oldest type of wood glue? It’s been around for thousands of years. This glue, made from animal hide tissues, creates a strong bond when joining wood pieces together. It’s available in pre-mixed form and in crystal forms that require mixing.
Hide glue needs a lot of time to work, similar to epoxy. But it also offers more bonding strength than some other glues, like CA. It’s not the easiest kind of wood glue to find, though, as it’s not used as much as PVA, epoxy, and CA.
Properties of hide glue include the following:
- Reversible when heated up — you can dissolve it and re-glue as needed
- Long open time
- Simple cleanup using water
Polyurethane Glue
Need an adhesive that’s waterproof or water-resistant? Polyurethane’s a good choice for these properties. This synthetic plastic resin works well in moist or humid environments. In fact, it can be a better choice compared to PVA for some projects.
Polyurethane glue isn’t a water-based adhesive, allowing it to hold oily or greasy wood pieces together securely. You can use it to connect end grains on your wood pieces. It’s able to penetrate wood deeply and uses moisture in the air to activate its bonding properties.
Other properties of polyurethane include the following:
- Low moisture levels for a lower risk of swelling
- Long open time before the bond starts to form
- Better results in warmer environments while woodworking — colder temperatures may cause the glue to fail
Polyvinyl Acetate (PVA)
Polyvinyl acetate, simply known as white glue, is a popular wood glues. It’s a highly versatile adhesive that you can use on nearly any kind of joint you’re making. It has a relatively fast set time — but takes about 24 hours to fully cure.
PVA seeps into wood, creating a powerful bonding strength that lasts for years. Just note that it may not be the best choice on visible joints, since it can creep and show up on surfaces. But it’s a great option for most projects.
What else makes it such a top choice for woodworkers? It offers the following benefits and properties:
- Long storage life for multiple uses over time
- Incredibly strong bond that’s stronger than the wood you join
- Quick working time that’s usually around 5 to 20 minutes
- Indoor use
- Affordability
- Easy cleanup using water
- High shear strength
Aliphatic Resin
This versatile adhesive, commonly called carpenter's glue or yellow glue, is the most popular of all wood glues. It combines easy application and water cleanup with superior bonding strength. Here are some other benefits:
- Long storage life
- Comes in water resistant and waterproof formulas
- Heat resistant
- Is sandable
- Dries translucent
How to Choose the Right Glue
How do you know which wood glue to use for your project? Consider all of the following factors to make your decision.
Viscosity
Do you need a thinner or thicker glue? Thinner wood glues are more suitable for smaller uses, like filling in cracks or making minor repairs. Thicker glues are better for creating a long-lasting, permanent connection between wood pieces.
Some wood glues, such as CA, have varying viscosities. You might also be able to add thickeners to glues like epoxy to get the viscosity you need.
Adhesive Strength
How much strength does your glue need to have? If it’s going to hold pieces of wood together for furniture, for example, it’s going to need a stronger bond. But you might not need as much adhesive strength in other situations, such as when you only need a temporary bond.
Choose a wood glue with high bonding strength, such as aliphatic resin, epoxy or PVA, for a more durable and permanent connection. You can use CA or other wood glues that aren’t as long-lasting when you need less adhesive strength.
Indoor vs. Outdoor Use
Is your woodworking project an indoor or outdoor one? Will it be exposed to humid conditions? These factors help you determine what type of wood glue to use. You’ll want something waterproof — like aliphatic resin, epoxy or polyurethane — for wood that’s exposed to humidity or water.
If those conditions aren’t a concern, you’ll have more options, such as PVA or CA — depending on other factors.
Working Time
Do you need an adhesive that dries fast? Or can you use glue that might need to sit overnight? Consider working time when choosing a wood glue. CA only takes about a minute to bond and dry. But PVA glues usually need a longer set time.
Shelf Life/Storage
How often do you plan on using wood glue? That depends on the kinds of projects you’re tackling. Or it might depend on how big your projects are. Note that wood glues have varying shelf lives. Some only last for months. Others, like epoxy, may last for years. Others, like CA, don’t last as long once they’re opened.
What happens if wood glue goes past its shelf life date? You can still use it — but it won’t work as well.
FAQs About Wood Glue
What Is the Strongest Wood Glue?
PVA, aliphatic resin, and epoxy are known for creating some of the strongest bonds when used for wood joints. In fact, PVA tends to end up being stronger than the wood it’s connecting! Different kinds of epoxy vary in bonding strength. But you can find epoxy that’s as strong — or even stronger — as PVA.
What Is the Best Wood Glue?
That all depends on what you’re using it for. What are you building? Or are you making repairs or filling in holes? What kind of wood are you using? Do you need it for indoor or outdoor use? Do you need something that works quickly or something that takes longer?
These are some of the factors to consider to find the best type of wood glue for your project.
How Long Does Wood Glue Take to Dry?
This varies based on the kind of glue you’re using. CA might only take a few seconds or a minute to dry. But PVA and hide glue might need several hours or overnight to dry.
What Glue Do Most Woodworkers Use?
PVA and aliphatic resin are the gold standards for many woodworking projects. They're the wood glues used most often. They may not be the best choice for all uses — but it’s a good idea to keep them in your shop.
How Long Does Wood Glue Last?
This can vary, depending on the type of glue. In terms of storage, some have a shorter shelf life. But in terms of application, some can last for years, such as PVA. Others don’t hold up as well over the years once they’re applied, such as CA. To extend the life of water-based glues, protect them from extreme cold where they may freeze.
What Are the Safety Precautions When Working With Wood Glue?
To keep yourself safe when handling these adhesives, do the following:
- Wear gloves to avoid getting wood glue on your skin
- Wear eye protection to prevent glue from splashing into your eyes
- Use clamps to hold your wood pieces securely in place while gluing
Eager to get started on your woodworking project? Make sure you have the right kind of glue first! Consider all relevant factors to determine which kind is best for your needs. With multiple options, you can find the most suitable type of wood glue for any project — from filling gaps to building furniture!