A Guide to Different Wood Glue Strengths
Using wood glue for a project can help it turn out strong and sturdy or, in a worst-case scenario, flimsy and weak. This will depend on the strength of the glue. Most people do not know that there are different strengths of glue. The "gap filling" qualities of some wood glues are substandard compared to others. Some wood glues bond well to wooden surfaces but not to themselves. Therefore, they cannot cope with excessive weight or too much movement.
Resin wood glue is one of the strongest, if not the strongest, types of wood glue. It is a durable and strong glue with high levels of resistance to water, solvents, and other substances. Resin glue is always made from a compound of liquidized resin mixed with a catalyst powder.
Phenol Formaldehyde Resin
Phenol formaldehyde resin is usually associated with the manufacture of plywood. It is the resin glue that is used between the layers of wood to create the ply. Therefore, using it as a wood glue for projects that involve plywood is perfect. It is a "gap filling" glue and it will bond perfectly to itself or other types of wood. It is also highly "creep" resistant and will not move under the strains of heavyweights.
Super glue, or cyanoacrylate to use its correct name, is a fast bonding and tight holding glue which is appropriate for almost any project. Super glue will bond metal to wood, wood to wood, metal to metal, and many other materials together. It bonds in seconds and holds for a long time. It is not susceptible to extreme heat or cold.
Many hobbies involve the use of balsa wood or other light woods and hobby glue is made for these projects. It is not a good glue for heavy wood projects like furniture or joinery but it will suit a modeler or hobbyist well. Hobby glue is commonly known as school glue or PVA glue and it totally non-toxic.
Epoxy glue, sometimes referred to as epoxy resin, is probably one of the most commonly used glues in the making of furniture. It has extremely strong holding power and is resistant to varying levels of heat, moisture, and cold. It will stick and bond to most other types of dried glue but it is affected by saltwater and UV light rays. Epoxy, therefore, is not suitable for outdoor projects.
Polyurethane glue is highly water resistant and can be used on wood projects in moist conditions and room like bathrooms. Its popularity and uses has increased over the last few years and it is becoming widely used in more of a variety of projects in place of previously preferred glues. Do keep in mind, however, that water-resistant does not mean waterproof and if polyurathane becomes saturated, it will be less durabile.