Many people might think of the brand names Super GlueTM or Krazy GlueTM as the strongest glue in the world. Those glues are actually a class or type of adhesives called cyanoacrylates, also known as instant glues. Remember that commercial of a man dangling from a metal bar with his hard hat attached to it? If you’re looking for glue in a strength-to-volume perspective, then cyanoacrylates probably do supply the strongest bond and they are very resistant to most chemicals, water and mild heat. However, they are not flexible so any amount of bending, expanding or contracting, they become brittle and break.
Others may think its two-part epoxies because they are strong, flexible, waterproof and resistant to heat, cold and chemical exposure. They are high-performance adhesives used in the construction of aircraft, automobiles and boats, and they can be developed to suit almost any application for wood, metal, glass, fiberglass, stone, and some plastics. While these adhesives provide high adhesion, low shrinkage and high fatigue resistant, the downside is it requires a lot of surface preparation, have a long cure time and can have a low peel strength.
Then some people may think of Gorilla GlueTM. This glue is a polyurethane adhesive that, like two-part epoxies, can bond to a variety of substrates, is resistant to water, heat and cold, and can be used for a variety of purposes. It’s faster setting than epoxy adhesives yet expands after it is applies, and, unlike epoxies, can be sandable, paintable and stainable. Polyurethane adhesives, however, generally do not have as high “lap shear strength” as epoxies. This lap shear strength is a measure of an adhesive’s ability to endure the force applied to bonded substrates that get pulled in opposite directions.
There are other adhesives out there that are considered the “strongest” but only relative to the application. For example, there are chemical adhesives that actually chemically bond two surfaces becoming as strong as the substrate they are applied to. There is even a bacteria that can attach to solid surfaces which is the strongest glue known to exist in nature but only develops in the presence of water.
So, in the end, being the strongest glue really depends on what you put the adhesive on, what the intended use is for, and how it is applied. Hence, it’s all relative. If you want to learn more about the available types of adhesives perfect for your adhesive applications, contact us at 440-486-7185.
Lynette Filson, Communications Manager