Welding, soldering, and brazing. Do you know the difference?

Are you someone who likes to know about things and is curious to know more every day? Or are you someone who believes they can/should do everything on their own? A lot of people like to do things with their hands either because they don’t like to depend on others for little things or because they want to save money. Among other things, welding, soldering, and brazing techniques intrigue many people because of how similar they seem. Despite their similarities, these are three different techniques serving different purposes. Let’s get to know them one by one.

Welding

Welding has the most long-lasting results when it comes to joining two metals. It joins them permanently and can be used to fill the gaps between two pieces of metal too. The most important thing to know about welding is that it works for two similar metals i.e. the two pieces you are joining should of the same metal. You cannot weld a piece of iron with gold using this technique. Welding takes place at a very high temperature. The welder uses an extra piece of metal while welding. This metal is called filler.

The filler binds the metal pieces together when melted at extremely high temperature. As mentioned earlier, welding has the most long-lasting results out of the three techniques. If the welder has not made any mistakes, the welded metal should be just as strong as the metal around it. However, a small mistake such as overheating the metals and fillers can result in a weak weld. Once two pieces of metal have been welded, they are like one piece.

Welding joints

 

Welders can join the metals in multiple ways using different joint types. The five main types of joints are:

  1. Lap
  2. Corner
  3. Butt
  4. Edge
  5. Tee

In addition to joints, there are four different techniques of welding. These techniques are called:

  1. Gas Metal Arc Welding
  2. Shielded Metal Arc Welding
  3. Gas Tungsten Arc Welding
  4. Flux Cored Arc Welding

Let’s go into the details of each welding techniques.

Gas Metal Arc Welding

Also known as MIG (Metal Inert Gas) welding, involves the use of a shielding gas. This gas helps in heating the two pieces of metals that you wish to join.

However, in order for this technique to work, you have to maintain a constant supply of voltage. You also need DC power source to weld metals with this technique. The good thing about this technique is that it is quite easy to learn. If you want to join metals at home, you will not take much time to master it. It is best that you use this technique to join metals like aluminum, stainless steel, and regular steel.

Shielded Metal Arc Welding

Welders often call this type of welding “stick”. This technique is quite basic and requires you to form an arc between the metals and the stick. Due to the fact that it is a basic technique, you can learn and use it at home to do basic repair work. Metals that you can weld using this technique include copper alloys, steel, iron, and nickel. This welding technique is commonly applied when constructing structures made of steel during industrial processes

Gas Tungsten Arc Welding

In this type of welding, workers use a non-consumable electrode made from tungsten to heat the base metal, resulting in a puddle of weld metal that melted off. In this technique, the autogenous weld is made when two metals are melted together. To use a gas tungsten arc welding for repairs and industrial purposes, it’s required that the user have plenty of skill before implementing it in a critical situation. This is due to the complex nature of the process. This type is usually applied when it is desired that the finish is of high quality but there isn’t enough time for grinding or sanding, later on, to clean up.

Flux-Corded Arc Welding

This particular welding method was developed as an alternative to shield welding. The procedure is similar to that of Gas Metal Arc Welding but with the exception that, in Flux-Corded Arc Welding, shielding gas is not required as much and a unique tubular cable packed with flux is employed. This particular welding process is commonly described as being easier and cheaper to master. Nonetheless, there are quite a few limitations, including the fact that this type of weld doesn’t always bring a pleasant aesthetic when compared to other techniques. For construction projects, the semi-arc variation of this type is applied since it welds quickly and the tools are convenient to carry.

While all these types of welding can be used in the repair, manufacturing and construction industries, there are still some differences when it comes to the durability, longevity, and finish of each weld. For this reason, it’s better to have enough knowledge about all four types so you can make an informed decision as to which one would suit your needs best.

Soldering

A skill commonly employed in the field of electronics and mechanics, soldering is a process that is quite often confused to be the same thing as welding. While there may be various similarities, including the process of melting, the two are quite different. Welding combines two different mental components – melting them together. Soldering, on the other hand, does this using a filler metal that joins both the components instead.

The filler metal- called solder- that is used to join two parts of differing metals has a melting point that is slower than that of the metal parts that have to be joined. This is so that small important metal parts are not damaged by melting. This explains why soldering is used in developing electronics and not welding. The skill has been practiced for centuries and has now developed to have more sub-techniques that can be used for specialized applications.

Soldering can be classified into different types like the image below.

In all of these sub-techniques, the process is similar to the extent that filler metal is melted and added to the area between closely spaced metal surfaces using an effect called capillary motion. The kind of solder applied depends upon the type of soldering technique being practiced and the metals that need to be joined together.

Soft Soldering

This type of soldering is commonly observed in industries like plumbing and electronics. The reason why this type is employed is it helps in creating small and minute electrical connections and connects metal-based electronic parts to the main circuit.

In plumbing, soft soldering is used for joining pipes and their connectors mostly made from copper. The solder metal used in this process needs a melting point lower than copper so a mixture of metals, such as tin, is used.

When applied for plumbing, workers add flux, a substance that’s acidic in nature, to the solder metal used to connect two pipes. This is so both pipes fit tightly together. The soft soldering process doesn’t require much heat, just a minimal amount of it from a soldering iron that’s powered by electricity or gas. Despite being the most commonly applied soldering technique, it creates weaker bonds compared to the others.

Hard Soldering

Compared to soft soldering, hard soldering requires higher temperatures to create robust and strong bonds using a solder with a higher melting point. Commonly, soldering metals that are used to connect two components are silver or brass, even.

These aren’t melted using a simple rod, and a worker will need to employ a blowtorch so that it can melt. The base metals are heated until the solder melts and as the combination slowly cools, a strong bond is created between the two.

When silver is used as the solder metal in hard soldering, the technique is called silver soldering. Although a silver solder has a lower melting point than brass, it’s a much pricier option.
In soldering, three different types of tools are used to get a good bond between two base metals. There’s a conical, chisel and spade shape. The simple conical shaped tip is commonly thought to be the only type of soldering tip but this isn’t true, though it’s easy to understand why. It comes with a slightly rounded tip, like a ballpoint pen, that allows for the smooth application of melted solder over the space between base metals.

The chisel type tip is also used for most soldering applications like the conical tip but the difference is that it offers a lot more surface area in comparison. A greater surface area is required if you want to be able to transfer heat easily from the heating iron to the base metal or electrical part. When there’s better transfer of heat, you’ll find that the melted solder flows more smoothly and gives a better finish.

Brazing

Lastly, brazing is a technique that lets you create sound and sturdy bonds by using a filler metal between two separate parts. Brazing is different from welding because it makes use of a filler metal instead of simply melting connectors of the metal parts themselves to create a joint. Moreover, a crucial difference is how one can create a sound joint between two dissimilar metals by brazing but can’t do the same with welding because the process requires that both metals be the same.

Brazing vs. Soldering

There is a minute difference between both brazing and soldering, with many experts calling them versions of each other. Essentially, soldering makes use of a filler metal with a lower melting point, below 840oF, to be exact. Meanwhile, brazing takes place when the solder alloy melts at a temperature higher than 840oF.

Despite being similar processes, there is a vast difference between the bonds created by each technique. Because of requiring a filler that melts at a higher temperature, brazing creates a stronger bond than solder. To be specific, the bond is stronger at the base of the connection where the filler comes in contact with the base metal.

The brazing technique is highly praised for creating a bond without causing any of the base metals to melt. Commonly, this practice is employed when the desired weld has to be seamless, strong and achievable within a scope of temperatures.

Filler metal is selected based on the shape and size of the metals that need to be joined and the type that a welder generally likes working with. This can be in the form of wire or stick. Start by setting the temperature on your torch so it melts the filler but not the base materials.

Process

Heat the joints of the base metal you’ll be connecting with the filler and then place your filler alloy on the joint. After positioning the filler over the joints correctly, heat it so that it melts and flows into space between them. You can make use of a flux to clean the surface thoroughly of any debris that can cause clumping and help the filler flow smoothly into the spaces. The melted filler will flow into the base of the weld so when it cools, creates a strong bond that can’t be broken.

Filler

There is a wide range of filler alloys that can be chosen from, to connect joints of the base metals. Each brazing filler metal is made using a combination of commonly combined base metals out there. For example, aluminum-silicon filler is used to bond aluminum and its alloys; copper-phosphorus is mostly used to bond copper and copper but can also be used for tungsten and silver. A magnesium filler joins alloys made from magnesium while a cobalt filler joins copper-based base metals.

Brazing Joints

There are only two types of joints used for a bond created by brazing; the lap and butt joint. The joint is selected based on the base metals being used, and whether, if either joint is applied, will allow ventilation of gasses and flow of flux material for a better spread of filler.