Types of Adhesives Explained: What to Use and When

Contact adhesive is an elastomer-based adhesive and a popular choice for tradies and DIYers. To work, it needs to be applied to both surfaces that are to be bonded. It's a rubber-based glue that cures without a chemical reaction. After application, it's left for around ten minutes so that the solvent can evaporate before the two surfaces are pressed together to form an instant, strong, and flexible bond.

It's a highly versatile adhesive, capable of bonding a wide range of materials including rubber, metal, leather, wood, and textiles - hence it's popularity.

Commonly known as threadlocker, this thermoset adhesive is a type of anaerobic glue that cures in the absence of air. It's specifically formulated to secure threaded fasteners like screws and bolts. Applied directly to the fastener before assembly, it forms a very strong bond once dry, which helps prevent them from vibrating loose.

The benefits of thread glue include enhanced resistance to shock and vibration, as well as protection against rust and leaks. This type of adhesive is typically used in industrial and automotive applications.

Wood glue, a thermoplastic adhesive, is designed specifically for joining pieces of wood. As you'd expect, it's common in carpentry and woodworking and can be used in conjunction with screws or nails to help increase structural integrity (e.g., when building a table or chair), or on its own for a neater, more polished finish.

While its non-toxic nature makes it popular for crafting, a significant drawback is its inflexibility, which makes it unsuitable for wood that could expand or contract in high-moisture environments. That said, when applied correctly, wood glue can last for many years. 

Glue sticks are a type of hot-melt adhesive to be used in glue guns. A thermoplastic adhesive, it's typically supplied in long cylindrical sticks and is melted in a glue gun before being applied. As it quickly cools, it solidifies to form a bond between surfaces.

Glue sticks can be used on materials like wood, glass, textiles, paper, and card. Although it dries very quickly, the bond it creates isn't as strong when compared to other adhesives. A key advantage is that the sticks themselves do not dry out if left exposed to air increasing their shelf life.

A type of thermoset adhesive, epoxy is a two-part system that consists of a resin and a hardener. When these two parts are mixed and applied, they react to create a very strong, rigid, and durable bond. Often referred to as epoxies or structural adhesives, they're highly effective when it comes to bonding different types of materials together, such as plastic to metal.

Considered one of the strongest adhesives available, epoxy can withstand high temperatures, stress, and other elements. Once cured, it can be sanded or painted, and it's suitable for both indoor and outdoor use making it versatile as well as tough.

Super Glue is a type of thermoset adhesive which cures rapidly at room temperature by reacting with moisture in the air or on the surface of the materials it's applied to. While it forms a rigid bond and is excellent for quick fixes and smaller projects, it doesn't expand as it dries, so it's not suitable for filling gaps like a hybrid adhesive / sealant.

It has a weak initial grab but sets very quickly, so surfaces may need to be held in place while it cures. It's also not effective on certain plastics, like polyethylene and polypropylene, due to their low surface energy, which prevents the glue from forming a proper bond.

Sometimes known as construction adhesive, grab adhesive is a type of elastomer that's designed to bond heavier materials to surfaces like walls and floors without the need for additional fixings like nails or screws. Its name comes from its strong initial "grab" or tackiness upon application. It can bond different materials, for example, metal to brick making it a versatile adhesive.

The curing process varies depending on the type, with some formulas curing through moisture contact and others via solvent evaporation. Some varieties may have a strong smell and can take up to 24 hours to fully cure, so keep this mind when using this type of glue.

Hybrid adhesive sealants are often based on silane-modified polymers (SMPs), which are a type of elastomer. They combine the flexibility of a sealant with the strength of an adhesive, making them incredibly versatile. They can be used on virtually all materials and are particularly good for bonding items that may be subject to movement or vibration.

Unlike most other glues, they remain flexible once cured, won't shrink when dry, and can be used to fill gaps. They're also UV stable, weather-resistant, and suitable for both indoor and outdoor use. Once dry, they can be painted over for a seamless finish, although they cannot always be sanded and can take a long time to fully cure.