Acrylic structural adhesives are commonly used to bond glass to metal in areas that light cannot reach. Examples include bonding metal clips and hinges onto glass doors and furniture.
Epoxy adhesives are the best choice for applications that require high temperature, environmental or chemical resistance. Such as bonding optical lenses in medical devices that will undergo autoclave sterilization.
UV Curable adhesives offer the most diversity and are found in a large variety of applications. They are ideal for both high speed production and manual applications. Generally speaking, the adhesive will not cure until it is exposed to UV light and will only cure during that exposure. However, a variety of hybrid adhesives are now available.
One of the hybrid adhesives is UV curable adhesive with a secondary anaerobic cure mechanism. One of the substrates (glass) allows UV light through, and the other substrate (metal) activates the anaerobic cure mechanism. The resulting process allows for an instant set with UV while the metal component activates the adhesive and continues the cure. Other hybrid adhesives include a secondary moisture cure system.
Although many manufacturers desire UV curable adhesives for high speed production lines where fast curing is desired. In other applications, such as in artistic bevel bonding, a slow cure is desired. The artisan prefers to set the glass in place with a partial cure, clean away any excess adhesive and then apply more UV light to complete the cure.
Industrial adhesive solutions for bonding glass are as varied as the items being produced. Typical glass bonding adhesive applications:
It goes without saying that the requirements of the glass bonding adhesive for a crystal figurine would be considerably different from the industrial adhesive solution required for stemware or headlamps.
To determine which will best suit an application, there are several factors to consider. Review the following and contact Permabond.
Substrates – Does the application involve other substrates, such as metal? When bonding dissimilar substrates, we must take the different coefficients or thermal expansion into consideration if the assembly will see temperature variation.
Obstructions – Can UV light reach the entire bond area? Some glass may block or attenuate UV light. In other applications (for example, a metal clip bonding onto a glass cabinet door) it may be difficult to get light between the glass.
Temperature – Understanding the upper and lower temperature limit as well as the ramp or shock time to reach the extremes is helpful.
Bond Area and Gap – The total bond area is helpful in determining strength. The gap is a critical factor in determining the correct adhesive.
Stress – Some adhesives are very strong in tensile, but don’t fair as well with impact. Knowing what type of stress is on the bond will aid in the selection of a quality adhesive. Others may do well with impact stress but not tolerate a lifetime of dishwasher cycles.
Please contact Permabond for more information or to help you select the best glass bonding adhesive for the application.