Wood glue comes in many forms. Each manufacturer claims that their stuff really gets the job done. So, what is the best glue out there. The answer turns out to be relatively simple.
PVA Glue Type I
This glue is as good as it gets (Tilebond III). It's waterproof and it's stronger than anything else. Don't get fooled by the space age ingredients on designer glues. For woodworking there is nothing better.
The only limitation this glue has is its short open time. You only have about 5 minutes to get your joints assembled. The bond will be stronger than the wood around the joint. This stuff really is the "ultimate wood glue".
PVA Glue (Yellow glue)
The cheaper stuff (Tilebond I) is only marginally weaker than the Type III. In most cases it reaches up to 99% the strength of the Type I glue.
Yellow glue is the cheapest wood glue on the market. Unless you need a waterproof bond, it's hard to recommend anything else.
Slow-set Epoxy
Epoxy glue (Gorilla glue) is as strong as type I glue. It sets slower and is also waterproof. It should be considered equivalent to PVA type I. If you are looking for long open times, don't hesitate to use this type of glue.
Hide Glue
Used for thousands of years hide glue (Tilebond hide glue) has finally been surpassed by PVA glue. It's joints are somewhat weaker, but only slightly. It sets slower, which may be an asset.
Hide glue is commonly used in reproduction pieces that are built to match their period original. It's also natural product and renewable resource.
Polyurethane
This type of glue (Franklin Polyurethane glue) is well off the pace. Studies have placed it at 3/4-1/2 the strength of a PVA bond. It is particularly weak on lose joints. The strength polyurethane glue achieves, however, is still plenty strong for load bearing applications in furniture.
On the plus side, polyurethane glues have the longest open time of any wood glues. Use this type of glue for large, cumbersome assemblies that take a long time to glue.
Summary
While all glues create a strong bond, there are clear favorites. Your base glue should be plain yellow glue. It achieves the same strength of the much more expensive glues.
If you need a waterproof joint, use Type I PVA glue. If you don't mind the extra expense, use this type of glue exclusively. It creates the strongest bond possible.
If you need a glue with more open time, look for a slow setting epoxy or polyurethane glue.
