Soldering and Adhesive Bonding

Introduction to Soldering and Adhesive Bonding

While working with metals to create products, the components of that object are separately made and have to be joined together to construct the finished product. Soldering and Adhesive bonding are the techniques implemented to achieve this objective. In soldering, a variety of metals are bonded together by melting with the help of “solder.” We would later find out what solder is. In Adhesive bonding, we join two surfaces together to lead to the formation of smooth bonds. We achieve this with the help of certain helpful materials called Adhesives. Both techniques are widely used in industries.

Soldering

Soldering is the process where we use the third element to join the surfaces of two elements. This third element is called the solder. It usually has a lower melting point than the two elements we are joining.

The difference between soldering and welding is that in welding, we melt the surfaces to join and fuse them into a mechanical joint. where as in soldering, a completely different substance acts as glue.

Since soldering isn’t an actual mechanical joint, solder joints are generally weaker than welded ones. Solder is actually a metal alloy generally, which consists of tin and lead, which is melted using a hot iron.

Adhesive Bonding

It is also a process of joining two surfaces using a third element. It is not only used for manufacturing purposes but also for repairing products. It is widely used not only in industries but also in households. Here the components are joined together using substances called ‘Adhesives.’ The bond created using Adhesive bonding is smooth.

The adhesives used are epoxy, glue, cement, and a wide range of plastics, acrylic, hot melt, silicone, etc. The bond is created by either evaporating the solvent or providing heat, pressure, time to adhesives. When the adhesives begin to solidify, the internal strength or cohesion of material increases resulting in the creation of strong bonds.

Welding

Another process helps in binding two surfaces together, but here instead of using an external substance, the original two surfaces are fused together on their own. This involves melting those two products using heat and then allowing them to cool, which causes them to fuse together. These elements are usually metals or thermoplastics.

Basic Principle of Welding

The basic principle of welding is to fuse two surfaces together through heating and cooling with or without pressure and usage of some filler. The bond or connection formed is called weld-seam. There are over 50 kinds of welding. Soldering also qualifies as a type of welding. Adhesive bonding is not.

Types of Welding

• Fusion Welding: Here, we form the bond using only heat and no pressure or filler metal.
• Pressure Welding: Also called ‘solid welding.’ As the name suggests, pressure and current are used to form bonds.
• Brazing: It is somewhat similar to soldering, where a substance with a lower melting point is used for bonding.

Metal Adhesive

Metal adhesives are also called metal glue which is a great way to join two metals for a range of purposes from simple DIY projects to industrial usage.

There are generally three categories of metal adhesives- superglues, epoxy, and polyurethane.

Epoxy Adhesives:

 In Epoxy adhesives, the Adhesive bonding is high-performing. They are mostly used for carpentry or other woodwork. So, it’s important while making furniture. Along with that, it’s also used for making creative costume jewellery.

Various types of epoxy exhibit different properties such as:

• transparent or opaque

• Fast or slow
• Rigid or flexible

Polyurethanes:

Their general use is for metals. Its main benefits are that it is water as well as UV- resistant. It also takes very little time to get settled. Polyurethanes are used for purposes such as repairing floors.

Superglues:

They work for a wide range of materials and are useful for almost all household fixes. It’s quite strong and simple to use.

Metal to Metal Adhesives

Let’s understand metal to metal adhesives. 

• Cyanoacrylate: works best for metal-to-metal joins. It’s like superglue and works very instantly. They work very well for metals on the condition that those metals are not reactive. Hence, they’re most suitable for brass and copper rather than steel. Due to its quality performance, it’s quite popular among miniature and modeling hobbyists.

Anaerobic metal adhesives: They are strictly used only for metals as they require the presence of metals and the absence of Oxygen to perform. However, they cannot be used for sheet metal bonding. It’s also not flexible; hence cannot hold out against flexible joint movements.

Conclusion

Soldering and Adhesive bonding– are the two most popular methods of joining two surfaces. Both of them require a third element that is adhesive or solder, to perform the bonding. Welding is yet another in-demand method and can be seen implemented from small industries to the largest ones. Here two surfaces are fused together on their own.

In order to join two metals, the metal glues or metal to metal adhesives come in handy. They include epoxy adhesives, polyurethanes, Cyanoacrylate, Anaerobic metal adhesives, etc. All of them provide different benefits, and we have to choose the suitable one based on their characteristics.