What is the difference between soft soldering and brazing?

We need soldering when we want to repair electronic equipment, but not only. We can also join metal plumbing components together or use the process for flashings. It is a very useful skill when we need to join two materials together. Then we can be sure that the connection is permanent and will not break so easily. To a large extent, we distinguish between two types of soldering - soft soldering and brazing. How do they differ and where do we use each? You can find out by reading this article.

Soft soldering

This type is characterised by soldering temperatures of up to 400-450 degrees Celsius. Most often, the process occurs as low as 320°C. We will use solder made of tin and lead or tin and copper. It is sold on the market in the form of sticks or powder. By soft soldering, we join metals such as copper, steel, brass, zinc and their alloys. A binder containing cadmium, bismuth or tin is used for this process. It is increasingly rare to find traces of mercury and lead in such a binder - they are poisonous and therefore worth paying attention to. Lead binds well, but is harmful to the body. This type of soldering can be used to join electronic parts, but will also work well in water installations or central heating assembly. Various types of wires can also be soft-soldered. A flame torch will work well for this process.

Brazing

Compared to the previous type, brazing is characterised by a higher process temperature, which can be as high as 900°C. There are many materials from which brazing is made. Copper is a metal that only melts at temperatures of over 1,000 degrees Celsius. Silver is often used in industry. Note that this solder should not be used to join copper and magnesium. Solders made of gold do not oxidise at high temperatures due to the chemical properties of this element. In addition, brazing can be made from cobalt and nickel. Brazing is recommended for joining stronger materials such as pipes, gutters and heating systems. It is also ideal for air-conditioning and refrigeration systems. The process can be carried out with propane-butane or acetylene torches.

How to solder?

Before soldering, the materials to be joined must be thoroughly cleaned. There must be no dirt or grease on them, as this will make the joint unstable. Then we choose which flux we are going to use. It is important to know that when joining the two copper components using copper-phosphorus solder, flux is no longer used. In other cases, it is needed. Once we have heated up the materials and the soldering iron, we can finally solder. We connect the required areas by making contact with the soldering iron and applying solder in the form of sticks or powder. The binder changes its state of aggregation and thus we obtain a liquid substance. When it dries, it will form a permanent and strong connection. When the process is complete, we can switch off the soldering iron and clean up the area where we worked. Regardless of the type of soldering, the process looks the same. So the only differences are the melting temperatures and the types of solder we will use.

If you want to expand your competences in soldering and welding, sign up for a course at the OSO Operator Training Centre. Here you will learn the necessary regulations and get to know these processes inside out. Our qualified staff will prepare you for any eventuality! Please do not hesitate to contact us!