Picking the right type of wood glue is critical for your woodworking project. But what is the best wood glue for you and what are the differences between each? Read on for more and learn about the five types of wood glue and their uses.
5 types of wood glue
- Polyvinyl acetate glue
- Polyurethane glue
- Cyanoacrylate glue
- Hide glue
Types of wood glues at a glance
|Type||Bond strength||Setup time||Cost||Versatility|
|PVA glue||Medium||10-30 minutes||Low||High|
|Polyurethane glue||Medium||30 minutes||Medium||Medium|
|Cyanoacrylate glue||Low||Instant to several minutes||High||Medium|
|Epoxy||High||Several minutes to several hours||High||Low|
|Hide glue||Medium||20-60 minutes||Medium||Low|
1. Polyvinyl acetate glue
Polyvinyl acetate (or PVA glue) is the most common type of wood glue. If you have yellow or white wood glue sitting around in your home, it’s almost certainly PVA glue.
PVA glue is popular because of its low cost, versatility for indoor and outdoor projects, easy clean up, and bonding strength. When dried, PVA glue creates a bond that is stronger than the wood itself, and it packs in an incredible shear strength. PVA glue is also water-based and water-soluble, which makes for easy cleanup. Apply the glue to your project with a wood glue brush, finger, or a wood glue dispenser, and then wipe with a wet rag to quickly remove any residue.
With their popularity, it’s no surprise that there are many PVA glues to choose from, including Titebond Original, Titebond 2 Premium, and Titebond 3 Ultimate, and Gorilla Wood Glue. These options are all water resistant, except for Titebond Original. Only Titebond 3 Ultimate is rated as waterproof.
Assembly times for PVA glues range from 10-15 minutes, for some Titebond products, to as long as 20 to 30 minutes for others. They all share that most take 24 hours to fully cure, and they are best applied at temperatures of at least 50 degrees to 55 degrees Fahrenheit. Their bonding strength ranges from 3,600 to 4,000 PSI.
Some PVA glues are food safe and rated by the FDA for indirect food contact. Yes, this means they can be safely used for cutting boards.
2. Polyurethane glue
Polyurethane is a synthetic plastic resin that is both water-resistant and waterproof. Its bond is activated by moisture in the air, so it works well in humid environments. But it’s versatile in many other applications.
Polyurethane glue shines in a few unique scenarios where PVA glues fall flat. Polyurethane glues can bond end grain to end grain well, besides being a great fit for oily woods. The fact that water and oil don’t mix also applies to wood glues. This explains why PVA, water-based wood glues don’t perform well bonding oily woods whereas polyurethane glues excel in this area.
The same theme applies to joinery with tight tolerances. Polyurethane glues don’t swell woods as water-based glues can.
Another unique feature of polyurethane glues is that they offer long assembly times of up to 30 minutes, along with a short clamping time. Unlike PVA glues, polyurethane glues are the best adhesive for finished wood.
The downside with polyurethane glues is that they’re more toxic than other types of wood glue and they are more costly. They also are more difficult to clean up, but not impossible — just apply acetone with a rag to remove squeeze out, or use a chisel or sandpaper when dried.
3. Cyanoacrylate glue
Cyanoacrylate (or CA glue) is a fast-drying acrylic resin with a tight and rigid bond. CA glue is the hobbyists’ name for what everyone else knows as super glue or Krazy Glue.
CA glues have a few advantages over other wood glues.
Firstly, they cure fast. On the long end, CA glues cure in just a few minutes. An instant cure can be accomplished with accelerator sprays combined with a few dabs of CA glue. Just mist the part of your workpiece that doesn’t include the CA glue, then press the two blocks of wood together for an instant bond.
CA glues are also transparent when dry, they come in a range of viscosities ranging from as thin as water to as thick as gels, and they don’t need clamps to form a tight bond.
But don’t reach for a CA glue for critical woodworking joints or when shear strength is important. Whack your woodworking piece with a mallet, and most CA glue bonds will break.
These properties make CA glues best for temporarily joining woods. One common use for CA glue is to assist in clamping angled joints that use traditional wood glues. Attach with CA glue two blocks of wood to your workpiece and you’ve now got a temporary bond for your clamps to hold on to that would otherwise be impossible.
Epoxy is a type of polymer with an incredibly high tensile strength ranging from at least 5,000 PSI to upwards of 10,000 PSI. Most epoxy resins come in two parts and must be mixed to activate.
Epoxy is waterproof and the cure times do vary by a wide range. Woodworking-specific epoxies such as JB WoodWeld Epoxy are set in 6 minutes and cure in one to three hours. Other epoxies can take days to cure.
Epoxies are most commonly used in woodworking to fill in cracks and voids. These wood glue properties can come in handy when you have a misaligned joint. Just mix sawdust and epoxy together and rub them into any gaps. While you can do the same with other wood glues, epoxies take a finish better and blend well into the finished wood.
The downside with epoxies is that they are expensive. They also don’t work well with acidic woods or when a wood block has remaining moisture.
5. Hide glue
Hide glue is made from connective animal hide tissues. They have a strong bond that can be upwards of 5,000 PSI, but it’s more common for them to be in the range of 3,000 PSI.
Hide glues excel in a few key areas. First, there are no VOCs. Secondly, hide glues can be heated to soften the bond and separate two pieces of joined wood. This is impossible with PVA glues, polyurethane glues, and epoxies.
The downsides with hide glues explain why they’ve fallen in popularity when compared to PVA glues. They must be heated to be applied, they’re not waterproof, have a short 1-year shelf life, and are hard to find. Titebond Hide Glue is one of the few hide glues still available for sale.
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