Brazing and Soldering Skills Required
Within the well established HVAC-R (Heating, ventilation, air conditioning and refrigeration) industry there are few skills so highly sought after and desired as the ability to perform brazing to a high standard.
Brazing is an essential skill within HVAC-R, and to be successful within this industry, the skill of brazing is absolutely something that you need to master. But for many who are new to the industry, there is some confusion as to what brazing actually is. This is typically because the term brazing is often (incorrectly) used interchangeably with soldering. There is, as it happens, quite a clear definition of what the two actions are, and although they are similar, it is important that the difference is observed.
Brazing is the action of joining two metals together by melting a non ferrous metal at above 800F. Soldering is the same process but is actioned at a lower temperature. This description makes the process all very straight forward, but it would be a mistake to consider that there is anything easy about the process. It takes time and effort to learn the techniques of both brazing and soldering. Once mastered however, they will surely help with your HVAC jobs.
To perform a brazing joint, you need some very serious pieces of equipment. It is important that you learn exactly what equipment that you will need for this. There are all different kinds of welding kits available, but until you know anything about the process, it would be unwise to set up your own kit.
It goes without saying that welding with a lit torch is exceptionally dangerous, and should only be performed by those that have had adequate training and support to learn the skills correctly. The secret to ensuring that your training is successful is to make sure that your teacher knows exactly what it is they are doing. The bottom line is that experienced teachers make for well drilled pupils. Since this is one of the most potentially dangerous activities within the HVAC-R industry, it is doubly important that you know exactly what you are doing when it comes to brazing and soldering.
Gas welding is a highly dangerous process, with the torch reaching very high temperatures. Add to this the risks of using compressed canisters of gas, and you have the recipe for a fairly major incident on your hands. Training for gas welding, whether brazing or soldering is hugely important.
With so many nuances to gas welding (brazing or soldering) there is no wonder that there is so much demand within the HVAC-R industry for those who have completed training on this subject.
There are techniques for every step to brazing, all of which the HVAC-R technician not only needs to be aware of, but needs to know every detail of how to perform them.
The initial step for brazing, soldering or most other forms of gas welding is to clean the two parts of the join, so as to ensure no oxidization on the joint. There are various techniques to this, each carrying their own benefit.
There are also various forms of flux that can be applied. Flux is what is used to ensure that the molten metal does not drip away from the joint, but rather falls where it is meant to. Once again, there are different options for flux, each with their own properties.
You would then be faced with numerous questions in order to connect the joint. Questions such as, ‘what temperature should I set the torch to?’ The answer to this is simple – the temperature of the gas welding torch should be higher than the joining metal, but only just. It has long been an understanding within the world of brazing that the lowest possible temperature should be used.
You are then faced with the question of ‘wetting’ which is the process of coating both sides of the join in the metal joining material. The hotter the gas welding torch, the more the material is melted down and becomes more runny and harder to use.
This article only really scratches the surface of the world of brazing and soldering within the HVAC-R industry. Brazing is an important skill, one which needs to be learned, and needs to be learned well.