Wood glue is quite strong, and the bond that’s formed after gluing wood together is much stronger compared to using nails or screws. For example, if you’re taking apart a finished project, it’s easier to separate the pieces that are put together by using nails.
However, I remember the first time I tried to separate two glued pieces of wood, and I ended up splintering the pieces instead of separating them. Glue bonds are quite strong and, for this reason, using different types of wood glue can help you build long-lasting projects.
In this article, we’ll talk about the different types of wood glue and what kind of materials they should be used with for the most practical and effective woodworking experience!
Which Factors Influence Glue Choice?
Not all types of wood glue will be suitable for every project. Depending on what kind of wood you’re trying to work on and stick together, along with the utility of the finished project, there are some factors you need to keep in mind before deciding on the right glue choice for your requirements.
- Water-Resistant Features: If you’re making a small decorative ornament for indoor use, it doesn’t matter if your glue isn’t waterproof. However, the glue that you use for your lawn chairs has to be waterproof in order to make sure that it doesn’t come off due to the elements.
- Food Storage and Safety: While some types of glue are safe around food, some options can be toxic and cause health problems if food is stored anywhere near them. If you’re making a shelf that will provide extra storage in your kitchen, you need to ensure that the wood you’re using is food-safe.
- Type of Finish: Some wood glue will dry without leaving a trace, while some might leave a lot of white residue once it dries. If you’re planning on sanding the wood and finishing it up with a layer of polish once you’re done gluing it all together, you can use glue that leaves a residue. However, if your project is going to be finished once the items are glued together, you might need to use glue that dries and leaves no residue.
- Timing: Some glue takes a few minutes to dry completely, while others can take several hours. If you’re working on a large project that requires multiple steps of gluing in the process, you might want to go for a faster drying glue to avoid wasting time.
- Shelf Life: If you’re a regular woodworker and you go through several packages of glue every week, you don’t have to be worried about shelf life. However, for people who pick up the occasional DIY project, considering the shelf life of different types of wood glue is important in order to avoid wastage.
Types of Wood Glue
Now that you understand the kind of glue you should be looking for when it comes to your woodworking project, let’s talk about the specific characteristics and examples of the most popular types available in the market today.
PVA stands for Poly-Vinyl Acetate and is by far the most popular glue used for woodworking. An advantage of this glue is that it’s available in white, yellow, and brown, which means that it can easily be used with wood of different types and colors.
The glue is also extremely easy to use. You can just open the bottle and start using it without needing to preheat it or put it through any other process. Because of its popularity, PVA is also easily available, and you can pick it from any hardware store down the street or order it online.
Price is another aspect of this glue that works in favor of the average woodworker, as the glue is quite inexpensive. The price and availability of this glue make it a favorite among people who want to create projects from home.
PVA is also quite strong. For indoor projects like decorative items or even furniture, you don’t have to be worried about the bonds coming off. With the right amount and application, this glue will make your projects last for years before they need any extra maintenance.
With a long shelf life, PVA glue will usually last you for more than a year even if you’re not a regular woodworker.
However, PVA glue does come with its fair share of disadvantages. First, the glue isn’t waterproof, which means that it can easily be washed away with water. If you’re making something for your lawn or patio that might be exposed to environmental factors, this definitely isn’t the right choice for you. However, it would work perfectly for indoor products.
Another disadvantage you might want to consider is when you’re finishing up your project, you might notice that you cannot stain over dried PVA areas. Painting over the wood can be a breeze, but staining won’t be possible because of the absorption of the glue in the wood.
The cure time for the glue also isn’t low, and you might have to wait for up to 24 hours for the bonds to solidify. This means that if you’re working on a project that requires quick drying so you can move on to the next step of the process, PVA might not be the best fit for you.
Extreme temperatures or weather conditions aren’t the right fit for PVA glue. Areas with a lot of humidity might cause the bonds to weaken, and so will extreme cold. PVA doesn’t hold up well when it freezes, which makes it unsuitable for external use if you live in an area with harsh winters.
Epoxy is another popular option when it comes to wood glue, but I’ve found that people are often turned away by the slight complications that are involved when using it. While PVA glue can be used straight out of the bottle, epoxy comes in the form of two different materials, namely the glue and the hardener.
While experienced woodworkers know their way around using epoxy, it might be intimidating for beginners. You have to mix the contents of the glue and hardener into the right ratio in order to ensure the best possible result. While most people get it right after a few tries, a lot of beginners prefer to go with simpler options.
However, the complications that come with epoxy bring with them several advantages as well. The resin has high mechanical properties and excellent adhesion to different types of materials. This means that epoxy can be used both as a glue and a filler material.
The material is also highly resistant to corrosion, and you don’t have to be worried about epoxy being damaged by water, heat, or extreme temperatures. If you’re building furniture that is going to be affected by environmental factors, epoxy is the right choice to make.
Storage of this material is also quite easy. I’ve had containers on my shelf for more than two years that worked perfectly the next time I used them. Just make sure you always store it in a cool, dry environment and you should be able to enjoy it for years.
When glue is dried out and completely crystallizes, the process is known as curing. Your glue needs to be completely cured for it to achieve its maximum possible strength. Most glues shrink when they’re cured, but epoxy doesn’t shrink a lot, giving you the best possible experience when you’re using the resin as a filler material.
The ability of the resin to bond with all kinds of fibers also makes it fit for not only woodworking but multiple types of DIY projects. Whether you’re working with wood, metal, or plastic in the workshop, you can always rely on epoxy to get the job done. You can learn more about this resin by checking out this scientific article about epoxy.
The strength of epoxy is unparalleled. If you mix it in the right ratio and wait for it to be completely dried and cured, you’ll have a better chance of breaking the wood than having the dried bond come off. For this reason, you should consider all your epoxy bonds as practically permanent.
However, there are some disadvantages to epoxy. First, the mixing requirement is, of course, a disadvantage. Getting the ratio wrong means either increased or decreased curing times and bond strength.
Epoxy can also be expensive. While PVA glue is very affordable and easily available, epoxy is a much more pricey alternative. If you’re undertaking your projects on a budget, this might turn you away from this glue.
Curing time is another aspect of epoxy that can cause some problems. While epoxy dries out quite quickly and can be used in projects with multiple steps, the curing time for this resin can be as long as 72 hours. This might be an issue for people who are looking for quick turnaround times.
Safety is also an important aspect to keep in mind when you’re working with epoxy. Because of the chemical properties and strength of the resin, always make sure you wear long sleeve shirts and gloves when you’re working with epoxy. If you’re working on a cured piece and you’re sanding the surface, you should also use a mask or a respirator to make sure you don’t inhale the dust.
While polyurethane glue isn’t as popular in woodworking circles as the previous two options, it’s still a good choice to consider. It’s not quite as strong as epoxy, but it still holds its own in the matter of strength when compared to PVA glue.
A distinct advantage of polyurethane glue is its curing time. While PVA and epoxy expect you to wait for 1-3 days for maximum strength, the curing time for polyurethane is as low as 8 hours. If you’re expecting a fast turnaround time, this could be the perfect option for you.
There are certainly disadvantages to polyurethane glue. One thing you need to note about polyurethane is that it works well with water. In fact, you need to slightly wet one side of the surface that you’re going to be using the glue on. The chemical properties of the glue ensure that this forms a stronger bond.
Therefore, if you live in a very dry area, you might have to wait longer for the glue to be completely cured. Conversely, this is a great alternative for PVA or for people who live in humid climates. While the moisture content in the air might affect PVA bonds negatively, it makes polyurethane bonds stronger.
Yes, hide glue is exactly what it sounds like. The glue is made from the connective tissue of animals. Skin, bones, and animal tissues can be used to make hide glue, giving it a gelatin-like consistency that works well with wood. While hide glue comes in different types, the glue made from the hooves of horses works best with wood.
If you’re not looking for a permanent joint like you would get with epoxy, hide glue is an excellent option. The joints created by hide glue are quite brittle, so taking them apart is as easy as administering a high-impact blow at the joint. These joints can also be separated by using water or heat.
The most interesting fact about hide glue is that it’s reusable. For example, if you’ve used a lot of hide glue in putting together a piece of furniture that you no longer need, you can repurpose both the wood and the glue by applying some heat to it. Once cooled after reheating, the glue will obtain its original properties.
If you want to stain your wood after finishing your work, hide glue dries transparently, making it easy to work with. It’s also easy to clean and can be washed off quickly from items of clothing.
The reversible nature of the glue also means that if you make a mistake while woodworking. I remember my second or third time using hide glue when I accidentally glued the wrong piece to a table, making it seriously wobbly. Just applying some heat to the joint reversed my mistake, something that would’ve been practically impossible with other types of wood glue.
As mentioned, hide glue isn’t waterproof. This means that as long as you’re using it for indoor furniture or decorative items, it will not be an issue. However, if it rains during the night and you used hide glue for your lawn chairs, you might just wake up to a bunch of lumber in your yard.
Unlike epoxy, hide glue cannot be used for filling up joints. This means that you’ll have to be extremely accurate with your woodworking measurements if you’re planning on using this type of glue.
The Bottom Line
When I first got started with woodworking, probably like most of you reading this article, I was confused as to which option would be the best for putting the pieces together. In my head, nails and screws were the only options, and glue was something secondary. However, after having worked with different types of wood glue, I have found that there are multiple advantages and disadvantages of using them.
If you’re looking for immediate results like you get with nails, glue is probably not for you. There are drying times and curing times involved with using glue that might need you to take a few breaks from your project.
However, if it’s a strong bond that you’re looking for, options like epoxy will give you unbreakable bonds that might just break the wood before you can even separate it. For ease of use, options like PVC glue let you open up a bottle and quickly apply it, much like traditional glue that you use on paper.
I hope that this article has given you a good idea of which types of wood glue are suitable for which conditions, and how each of them has its advantages and disadvantages. You should be able to make an informed decision about what you want based on the information provided in this article.
If you’re new to woodworking, or even if you’re a seasoned woodworker looking to expand your area of expertise, Woodworking Toolkit has a lot of informational articles, reviews, and buying guides that can help you learn more and improve your skills. Please feel free to check them out!
Last Updated on October 11, 2021 by Tom Bradly
The post An All-Inclusive Guide to Different Types of Wood Glue appeared first on Woodworking Toolkit.