Joining and Assembling Metal
You’ve made it this far. You’ve got a high quality design, all the specified Metal parts, and the manpower to get the job done. Now, it’s just a matter of Assembly. Depending on how your project is designed and specified, you might follow one (or more) of five or so assembly methods.
Here we’ll take a look at what these methods involve as well as the advantages of each.
Welding is, perhaps, the most common way to join metals together. In this method, applied heat melts and fuses metal parts together so that they become one solid piece. As a practice, Welding focuses on strength, durability and, most importantly, permanence. The main idea behind the welding process is to create a joint that is strong and can withstand stress over the long term.
There are a couple of variations of welding and these include MIG and TIG welding, seam welding, oxy acetylene, electric arc welding, and spot welding. While each of these methods employs the same heating and fusing process, the type of material being welded and tools being used may differ.
In mechanical assembly, hardware and fasteners like bolts, screws, and nuts are used to attach various metal parts. Unlike some other assembly methods, this type of assembly is not permanent. And in comparison to a technique like welding, mechanical assembly is also less durable as it frequently requires maintenance, adjustments, and replaceable parts.
Brazing and Soldering
Brazing is a process that uses a heated brazing rod, also known as a spelter, to join materials like steel and copper. The rod, which is an alloy of copper and zinc, acts as a filler to join the metals together. It’s usually heated to very a high temperature, often somewhere between 870 and 880 degrees Fahrenheit.
Soldering is nearly the same process, but with two exceptions. The first is that the heating temperature can fall way below 800 degrees. The second is that soldering is mainly used to make electrical connections, such as in electronics and circuit boards.
There are two types of soldering for joining metals: hard soldering and soft soldering. In hard soldering, the lowest melting point is 625 degrees Fahrenheit. And in soft soldering, the melting point is about 200 degrees Fahrenheit.
Although similar in practice, brazing and soldering are different in theory. Brazing works more like an adhesive to fuse materials together. Soldering, on the other hand, is about making that electrical connection we mentioned earlier.
Rivets are permanent mechanical fasteners that come into play when welding is either difficult to do or illogical for the application. Rivets can easily achieve the desired assembly with as much strength and permanence as a traditional weld might offer. They’re most noted for their shear strength and ability to be used on assemblies with different types of materials.
Another way of forming a strong and durable bond between metals is to use adhesives. Adhesives form a permanent bond that cannot be broken without destroying certain components of the initial assembly. In order words, once you use an adhesive, it sticks forever (in some form or another). Adhesives take many forms including liquids, pastes, emulsions, and tapes. These can either be applied manually by hand or by brush or semi-automatically with extrusion or spray guns.
One of the advantages to using an adhesive, like tape for example, is that it can significantly reduce the weight of the assembled application. Adhesives are light in weight compared to mechanical fasteners and other assembly components, making them ideal for applications where weight is an important factor. Another advantage to using adhesives is that no weakening or distortion occurs during the assembly process which preserves the integrity of the metal.