2 Misconceptions About Adhesives

Adhesives play an important role in all stages of residential construction. From framing the house, to putting up the drywall, and even more. At TYTAN Professional we see two common misconceptions about adhesives: that all adhesives are the same, and more adhesive leads to stronger bonding. This article will address these misconceptions.

A common misunderstanding is that all adhesives perform identically, regardless of type or application. Glue is glue, right? In reality, adhesives are a diverse category of materials with different chemical and physical properties that lend themselves to specific applications.

Adhesives can be broadly categorized into natural and synthetic types, with subcategories ranging from animal glues to cyanoacrylates, polyurethanes, etc. Each adhesive’s bonding mechanism can vary greatly. For instance, some work via mechanical interlocking, others form covalent bonds, while some rely on Van der Waals forces (Pocius, 2012).

In the case of TYTAN Professional polyurethane adhesives, when the adhesive is applied to a surface, the molecules of the adhesive are attracted to the molecules of the material (like wood, plastic, or metal). This attraction, partially due to van der Waals forces, causes the adhesive to stick to the material, forming a bond that holds the two surfaces together.

While van der Waals forces do contribute to adhesion, they aren’t typically strong enough to form a durable bond on their own. They work in conjunction with other types of physical (mechanical interlocking) and chemical bonding (such as covalent or ionic bonding, depending on the specific materials and adhesive involved) to create a robust adhesive bond.

Additionally, the effectiveness of adhesives can depend on the surfaces to which they are applied. An adhesive that works well on porous surfaces like wood might not adhere effectively to non-porous surfaces like metal. It’s also crucial to consider factors like temperature, moisture, and stress, which can affect adhesive performance. Therefore, it is paramount to choose the appropriate adhesive for each specific application.

The principle of “more is better” does not always apply in the context of adhesives. Contrary to popular belief, applying more adhesive does not necessarily result in a stronger bond. In fact, it can sometimes lead to weaker bonds or even bonding failure. By “more” I do not mean “denser” adhesive, I literally mean more adhesive. I have seen users that want to just layer the adhesive on over and over, resulting in this pile of adhesive that does not help your application.

As per Pocius (2012), the ideal bonding layer should be thin and uniform. Thick adhesive layers can lead to longer curing times, and uneven stress distribution, which can compromise bond strength. Thus, using an excessive amount of adhesive could prove counterproductive.

In the below gif, you can see our product manager James applying an appropriate amount for his application:

There’s also a practical concern that arises from using excessive amounts of adhesive: cleanup and aesthetics. Excessive adhesive often squeezes out from between the surfaces it’s meant to bond, leading to waste and necessitating cleanup. Depending on the application, this overflow could not only mar the appearance of your substrate but may also potentially damage surrounding materials or mechanisms. Beyond these optimal points, the adhesive’s ability to cure properly can be compromised, leading to lower bond strengths. Thus, judicious use of adhesives, taking into account the manufacturer’s recommendations for application (such as on our Technical Data Sheets), can enhance both the aesthetic and performance outcomes.

In conclusion, adhesives are not a monolithic category of materials, but rather a diverse and multifaceted group, each with their unique properties and uses. The principle of “more is better” does not apply to the use of adhesives, and they serve multiple functions beyond simple adhesion. Understanding these points is crucial to utilizing adhesives effectively and ensuring the longevity and reliability of adhesive bonds.

If you are interested in learning more about our polyurethane adhesives or have questions about a specific application, please reach out to your local TYTAN Professional Representative. You can also give us a call at (817) 381-4427.

Sources

Kinloch, A. J. (1987). Adhesion and adhesives: Science and technology. Springer.

Pike, Roscoe A. (2022). “adhesive”. Encyclopedia Britannica.

Pocius, A. V. (2012). Adhesion and adhesives technology: An introduction. Hanser Publishers.