The best products to fasten metal surfaces: structural adhesives
What are the best products to fasten metal surfaces? It is well known, metals are materials particularly suitable for the use of adhesives, due to their high surface energy. It is therefore possible to easily forego classic methods for the assembling of metal elements, such as welding, the use of screws or rivets, employing, instead, one of the many different products meant for fastening metals. The advantages are many: for example, noisy and vibrating processes, such as drilling, can be avoided; it is possible to completely eliminate any impact on the design, without having to deal with either screws or obvious welds. Moreover, adhesive fastening is instantaneous, homogeneous, and does not add weight to the product or to the metal structure.
In short, there are many elements that should push companies to consider the idea of using the best adhesive products to glue together metal surfaces. Adhesive products can be divided into different categories: there are adhesive tapes or double-sided metal tapes, sealing systems, as well as structural adhesives. Here, in this guide to choosing the best products for the fastening of metal surfaces, we will focus on structural adhesives meant for use on metals.
What are structural adhesives meant for use on metals
From a certain point of view, it could be stated that structural adhesives are the best products to fasten metal surfaces. Just because of the simple fact that these are the most powerful adhesives, which means that they have a higher load capacity: structural adhesives meant for use on metals offer, in fact, higher performance than tape rolls or adhesive sheets, even higher than acrylic foam tapes. The best structural adhesives for use on metals reach an overlapping shearing strength of 40 megapascals, thus bearing over 400 kg/cm² (5689,33 lb/in²) of surface.
When to use liquid adhesives for metal fastening
It’s clear, then, that liquid adhesives can be stronger than sheet or double-sided tape rolls. But beware: it is not entirely accurate to say that structural adhesives are the best products for fastening metal surfaces. It all depends on the application field.
It is necessary to consider the application in and of itself. Sometimes, quite simply, very high performance is not needed. Other times, the surfaces are so large that it is absolutely convenient to use thin adhesive tapes or sheets. When fastening thin metal panels, for example, in most cases it is preferable to use thin adhesive sheets: in this scenario, using structural adhesives could be useless or even harmful, as the cost would be higher.
To figure out how to choose between structural adhesives and double-sided adhesive tapes for metals, then, it’s best to consider the type of material, the available surface, the load to be borne, the presence of vibrations, the temperatures at which the object will be exposed, and so on: comparing these conditions with the characteristics of individual adhesives, liquid or strong double-sided adhesive tape, then, will reveal the best products for your needs.
Two examples of structural adhesives meant for metals
Because of their high performance, structural adhesives are among the best products for fastening metal surfaces. Here are two examples of 3M products, both from the Scotch-Weld line. These are, then, two-component liquid structural adhesives, which are characterized by high load and shock resistance, as well as high overall performance. How can these two adhesives differ from one another?
DP8407NS 3M™ Scotch-Weld™: not just an acrylic adhesive, but also epoxy. So, this structural adhesive mean (not only) for metals includes the characteristics of both these adhesive families, with moisture resistance, adhesion speed, ability to glue even powder-coated metals, and so on. It can be used with satisfactory results virtually on any metal surface: steel, stainless steel, aluminium, galvanized steel, copper, brass, bronze, powder-coated metals, epoxy, or polyurethane paints. In short, a powerful and very versatile structural adhesive.
DP490 3M™ Scotch-Weld™: This structural adhesive is less versatile than the 8407 model we have just discussed, while still showing good stability performance with static loads and dynamic loads, resisting both shock and vibration. It is, therefore, in these latter cases that this adhesive truly shines. However, the 490 model works well on almost all metals, from steel to aluminium, from copper to bronze, but not on painted surfaces.
To use the 3M liquid structural adhesives belonging to the Scotch-Weld line, you will need to operate the appropriate manual applicator, that is, a manual “gun” allowing you to dispense the adhesives from their special Duo-pack cartridges. The 3M application system also includes plungers and special mixing nozzles.