Brazing refers to the art of joining metals in which two or more metals are joined together by way of melting and then flowing a filler metal into the joint. This technique works by using a filler metal that has a lower melting point than the metals being joined together. Just as in the case with welding, soldering and related works, brazing is primarily pursued as a trade. However, there are rare instances where this art may be pursued as a hobby as well.
Due to apparent confusions between brazing and similar metal works, it has not been crystal clear what differences exist between the various forms of metal works. This article seeks to demystify that question by delving into all the details about brazing.
Differences Between Brazing and Soldering
The first difference between brazing and soldering lies in the melting point of the filler metal used.
In both cases, the filler metal used should have a melting point lower than that of the pieces of metals to join. In the case of brazing, the melting point of the filler metal should be more than 450 degrees C but lower than that of the base metal while in the case of soldering, it should be lower than 450 degrees C.
Another difference between brazing and soldering is in regards to the temperature conditions necessary for either of the two processes to be completed. In the case of brazing, it is observed that temperature may go up to 600 degrees C while in soldering, the favorable temperature is one that only goes up to 450 degrees C.
When it comes to heating the base metal before the joining can take place, we see that brazing requires metals to be heated, albeit below their melting point. On the other hand, soldering does not require the base metals to be heated at all.
Lastly, the strength of the joints is also a point of difference between the two processes; it is observed that joints made through brazing are stronger as compared to those made through soldering.
Differences Between Brazing and Welding
To start with, the most noticeable difference between brazing and welding lies in the use of filler metals. While brazing solely relies upon filler metals to have two pieces of metals joined together, welding uses heat or pressure to join two pieces of metals, with or without the filler metal.
The temperature conditions for these two processes are yet another difference. As already seen, brazing requires a meager 600 degrees C to ensure the success of the process. However, for any two pieces of metals to be welded together, a whopping 3800 degrees C is required.
The melting point is yet another significant difference between these two processes. While brazing requires the metals to be heated below their melting point, welding calls for the metals to be heated till each of the reaches their respective melting points.
It is also noticed that the changes in the mechanical properties of base metals is often negligible in brazing but in welding, these changes are more profound due to heating and cooling.
Lastly, brazen joints are weaker compared to welded joints. The latter are by far the strongest joints of metal work, stronger than both the brazen as well as soldered ones.
Howcast has a nice video explaining the differences between brazing, soldering and welding. You can watch it below.
What’s the Skill Level Needed for Performing Brazing?
For one to become a brazer or brazing technician, you must have gone through training in the relevant technical institutes that offer courses in this area. The intensity of the training programs vary depending on the institution that offers the training programs as well as the desired level of knowledge required.
As a general rule, however, the training program ranges from three weeks to a couple of months and it involves both theoretical lessons in a classroom as well as on-site practical lessons.
Aside from vocational-technical institutes, formal brazing training is also offered in many high schools, vocational schools community colleges as well as private brazing schools. In addition, there is an arrangement where an employer may sponsor on-the-job training. Knowledge in chemistry, metallurgy, mechanical drawing, physics, mathematics and computers is key to the success of a brazing training program.
Once you are through with the training program, you receive certification which involves going through a practical test in an independent testing lab. Once you pass the tests, you are graded by certain codes and standards based on your ability.
In addition to the education qualifications of a brazer, he should also posses other skills such as hand-eye coordination, manual dexterity, good vision and resilience to work longer hours bending or in any other awkward position.
Various brazing accessories
There are many accessories used in brazing work, the following are just some of those.
Brazing alloys – Used for joining, maintenance and repair of steel, stainless steel and copper parts. Copper to copper rods– Used for several brazing needs. Powdered flux – Used for a variety of brazing applications. Filler materials – Used for joining the metals together. Brazing torches – Used for joining together the pieces of metals to be brazen.
Dangers and Cautions During Brazing
Brazing is as dangerous an activity as it is important. For starters, the first risk associated with this activity is that it poses to your eyes as a result of the radiant energy emitted during the process. It is advisable you wear protective eye shades to reduce the effects of this light which could cause impaired vision in the long run.
It is advisable you wear protective eye shades to reduce the effects of this light which could cause impaired vision in the long run.
Secondly, it is important to note that brazing also exposes you to smoke and fumes that could threaten your respiratory health. In order to safeguard against this, you could invest in proper gar masks.
Additionally, brazing exposes you to fires and explosions that could cause a series of injuries such as burns. This calls for extra caution when working in the workshop as some of these hazards can be prevented or at least managed better if detected early enough.
Lastly, there are long-term effects associate with using braze alloys with Cadmium. These alloys are known to contain carcinogenic properties that may threaten the life of the brazer in the long run. To remedy against this, it is advisable to use alloys that are free of Cadmium.
Applications of Brazing
The first use of brazing is in the electrical and electronic industries for binding pieces of electrical materials.
Brazing is also used in the transport industry to repair and join different movable parts of transport vessels.
The appliance industry is not left behind either. Appliances such as air conditioners, condensers, evaporators, refrigerators and freezers all use brazing technology in one way or another.
Last but not least, brazing technology may be used in the manufacture or repair of jewelry and related items.
Leading Manufacturers of Brazing Equipment
The following is a list of some of the leading manufacturers of brazing equipment in the world