5 Types of Wood Glue
Wood Glue Types
There are different types of wood glue and you need to about wood glue advantages and disadvantages for your project(s). The basic wood glues are:
- polyvinyl acetate (PVA)
- animal or hide
1. Polyvinyl Acetate Glue
The most common type of wood glue is polyvinyl acetate (PVA). This is the modern wood glue that replaced hide glue. Titebond, Elmer's Glue, and Gorilla Glue are some of the most common names that come to mind for PVA wood glues.
There are several benefits to PVA wood glue. One of the biggest benefits is that PVA wood glue is the most popular wood glue around and is easy to purchase at most every large retail store from Home Depot to Walmart. Some glues will change color with time, such as regular Elmer's glue which is a PVA glue but not intended for wood and generally a weaker solution but some will use it for small projects. But PVA wood glue won't yellow over time and it will stay somewhat flexible and this helps keep the sheer strength strong over time.
The fumes are not foul or harmful, and is only toxic if you ingest it. A strong suggestion to make sure not to ingest PVA glue is being stated right now. There is little to no break-down over the years with PVA wood glue, although if the glue-up is poor quality it will still come apart.
PVA glue has several different variants, there are water resistant, dyed, water-proof, and probably many more that I don't know about. Depending on if the project is interior or exterior determines what type of PVA glue I will use. The other choice that helps my decision is cost, most of the PVA glues are about the same in my opinion. Although, I am liking the for interior work because it is thicker and dries fairly quickly. It was developed for miter work on trim etc. and is recommended by Titebond for end grain to end grain glue-ups. Titebond No-Run, No-Drip
This type of glue is used for pretty much every type of woodworking project. The biggest considerations are price point and what environment your project will be in. I know plenty of people who use Titebond III for pretty much everything, although this can be more expensive in the long run. PVA is a great general woodworkers glue to use, although for fine wood projects there are precautions that need to be taken so no surface is discolored or imperfect.
2. Polyurethane Glue
Polyurethane glue has a very strong adhesion if used correctly. Polyurethane glues do take some getting use to but it is recommended by professionals like Craig Thibodeau. Some of the benefits of a polyurethane glue is that doesn't have a high moisture content and doesn't make the joint swell like some water-based glues do. This is because polyurethane glue is not water-based and wood pores don't draw this type of glue in as much.
An interesting aspect of polyurethane glue is that you can still glue together finished pieces instead of having to glue the piece together first and then finish it. This is because the bond doesn't require an uptake into the wood pores and adheres the pieces together differently than other types of glue.
Another unique feature with polyurethane glue is that the glue cures from a chemical reaction to moisture. This makes gluing wood with a high moisture content or an oily wood easier to glue over a glue such as PVA, which would have difficulty bonding these types of surfaces at all.
There is a long cure time with polyurethane and I would suggest leaving the pieces clamped for 24 hours in order to assure proper adhesion. Although, you can use mineral spirits to clean excess up or a scraper and sandpaper to clean up squeeze out.
3. Cyanoacrylate Glue
Cyanoacrylate (CA) glue is most popular as super glue, but this is not the extent of CA glue. There are many one part CA glues, Super Glue, Krazy Glue, etc. The holding properties are good, but the sheer strength is not the best. These glues are great for gluing wedges to pieces and using them for clamping assistance, then because the sheer strength is low you can hit them with a mallet and pop them off when the adhesive has dried. This type of glue can be used for general purpose gluing, but it is more expensive than PVA and other glues. This is a glue that is great for crown molding, trim, and furniture repair because it is clear and can cure quickly.
I personally use CA glue for inlays. Since there are different viscosity ranges for CA glue, I use the with Insta-Cure+ and this goes throughout the powder or dust I am using and creates a great bond for the inlay and then treat with Insta-Cure+ to cure and create a solid inlay. Bob Smith Industries Super Thin
4. Animal or Hide Glue
Hide glue is the original glue. This is still widely used for bow making, instruments, and traditional woodworkers. Hide glue, animal glue, and rawhide glue are one and the same, but the term hide glue is more common. Hide glue is easiest enough to make as well. Although, there are synthetic hide glues on the market. Titebond Hide Glue is one such product that has a slight edge over natural hide glue. Natural hide glue does have more tack than the synthetic but the holding power of a synthetic is about the same with a better storage state. Below is a youtube video by Greg Pryor Homestead on making hide glue. A good mixture is 1 part rawhide to 2 parts water.
5. Epoxy Glue
Epoxy glue is another strong adhesive. This type of glue is a two part mixture that has a chemical reaction when combined, both of these parts are liquids. Epoxy is waterproof and makes a good filler as well. The cure times for epoxy can vary a great deal, but a general rule of thumb is the longer it takes to cure the stronger the bond is. This is an advantage that epoxy has over PVA glue. Epoxy is a good choice if your joint is off and needs a little filling, you can mix saw dust into the mixture for the wood texture.
A disadvantage to epoxy is that acid and moisture can interfere with the adhesion so there are some woods that are harder to glue-up with epoxy. Oak is a good example of an acidic wood that may have difficulty with epoxy. Another down side is that epoxy is more expansive than PVA and hide glue.
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© 2018 Chris Andrews