MIG welding and brazing are both useful techniques to know in order to make strong, reliable repairs or to just join pieces of metal for do-it-yourself projects. While these techniques have a few similarities, they also have quite a few differences. So, what are the differences between MIG welding and brazing?
Here are the differences between MIG welding and brazing:
- Different process of how the weld is formed.
- The temperatures used
- The types of materials used
- What happens to contaminants on the metal
- The welds look different.
- Different applications for MIG welding and brazing.
During this article it may become apparent that these processes have some very similar aspects, but the differences between them is what sets them apart. Continue reading to discover exactly what those differences are and the advantages that come with using these techniques.
The Differences Between MIG Welding and Brazing
If you are ever in need of making repairs or just enjoy making objects using metal, then MIG welding and brazing are two skills that could really come in handy. They are both process that join pieces of metal together by using heat.
Both are fairly popular and simple to learn, but what are the differences between the two?
The Process of Making the Weld Is Different
One of the biggest differences between MIG, also known as metal inert gas, welding and brazing is the process by which a molten pool, or weld, is made. The molten pool is the material that will cool and harden to join the pieces of metal together.
In MIG welding, the molten pool is formed from welding wire that is being fed through a type of welding gun, which is typically powered by an electric or gas welding machine. This welding wire will make an electrical path with the piece of metal that is being worked on, also known as the parent material.
Once the electrical path is made, an arc is formed. The arc is the heat source that melts the two pieces of metal together so that they can be joined in a process called fusion.
In brazing, a propane or oxy-acetylene torch is used for the heat source. The torch is then used to melt a brazing rod, which is commonly copper, silver, or nickel alloys. Once the brazing rod has been melted onto the workpiece, it flows over the workpiece through capillary actions.
In other words, MIG welding requires a welding machine with welding wire to make an electrical circuit with the workpiece so that a molten pool can be made, while brazing only requires a torch and brazing rod for a molten pool.
The Melting Points for the Materials Used Are Different
Another big difference that sets these two apart from each other are the temperatures that are used to make the molten pool.
For MIG welding, it is essential that the welding wire have a much higher melting point than the workpiece. This will cause the parent material and the filler metal to melt together and form a strong joint once the weld pool has cooled.
The welding wire is commonly carbon steel, stainless steel, or aluminum, which have very high melting points. Temperatures for MIG welding reach up to about 3000 degrees Fahrenheit (1,650 degrees Celsius).
In brazing, the brazing or filler rod has to have a much lower melting temperature than the parent material, so that the rod is the only thing that is being melted. The parent material will not melt. It will, instead, keep the molten pool on its surface without any properties of the base metal being changed.
As mentioned earlier, these brazing rods are typically metal alloys which have low melting points.
Here are some of the most commonly used types of metal alloys for brazing rods:
- Nickel alloy
The temperatures for brazing are much lower reaching only to about 850 degree Fahrenheit (450 degrees Celsius).
The Types of Materials Used Are Different.
The next thing that sets MIG welding and brazing apart is the materials that are used for these processes. Not only do they require different materials to make molten pools, but they also require different materials to work on. There are a few guidelines to keep in mind for both MIG welding and brazing.
For MIG welding, all of the metals need to have similar properties. Metals that are too different from each other just simply cannot be welded together. So, you have to use the two same alloys in MIG welding in order to make a strong weld.
For brazing, the materials do not have to have similar properties. It would make the best weld to use metals that do have similar properties for brazing, as well, but it is not necessary.
The reason why this is possible for brazing is because the two different metals do not come together in a fusion process like they do with MIG welding.
The Way Contaminants React to the Different Processes Are Different.
Another big difference between MIG welding and brazing is what happens to the contaminants in the weld pool.
Contaminants can be anything that was not cleaned off of the piece of metal that you will be working on. This can be dust or dirt and anything else that does not belong on your clean workpiece.
Since MIG welding requires extremely high temperatures, the contaminants will mostly burn off or get mixed into the molten pool. While this may seem like it is okay to not clean your piece of metal if you are MIG welding, that is not true.
Any contaminants in the weld pool can cause porosity, which will cause the weld to be weak and unreliable.
For brazing, the temperatures used are much lower. In fact, too low to simply burn off any unwanted contaminants that did not get cleaned off. So, during brazing, the heat will, instead, change the contaminants into layers in the molten pool.
The layers that are formed from the contaminants will prevent bonding. It is extremely important, for both processes, that the metal workpiece is cleaned thoroughly before you begin working on it.
The Welds Made from Each Process Look Different.
The next difference between MIG welding and brazing is how the welds look when the processes are completed.
Since we already know that MIG welding requires much higher temperatures in order to make a weld, it will probably come as no surprise that a MIG weld or joint can sometimes look a bit rough. The high heat can cause distortion in the metal, making the weld look rigid and rough.
A secondary finishing is required to clean up the weld in MIG welding which will also help to make stronger joints.
Brazing on the other hand does not use those extremely high temperatures which causes there to be less distortion and damage in the metal. This makes for a neat and clean joint without even using a secondary finishing.
Different Applications for Each Different Process.
The last difference between MIG welding and brazing is the applications that each are used for. While they are both used to join metal, each process works best for different types of repairs and work.
Here are some applications that are made from MIG welding:
- Mostly used in repair shops
MIG welding is typically used in cases where a very strong joint is required, and the appearance of it does not necessarily need to be approved by a customer.
Here are some applications that are made from brazing:
- Electrical work
Brazing is typically used in situations where two different pieces of metal need to be joined that have dissimilar properties. You will also use brazing in a situation where you would not want to change any of the metallurgic properties of the metal that is being worked on.
Since joints that are made from brazing look clean and smooth, it is commonly used in situations where a customer would notice the weld and joint and want it to look perfect.
The Similarities Between MIG Welding and Brazing
Now that we know what the differences are between MIG welding and brazing, let us take a look at the similarities between the two.
Here is how MIG welding and brazing are similar:
- Both are metal-joining processes. Each process achieves a solid, reliable joint in very different ways, but the goal for both is to join two or pieces of metal together.
- Both use heat to achieve a solid joint. The temperature ranges may be completely different for each of these processes, but they both still require enough heat to melt at least one piece of metal.
- Both use flux. Flux is a protective coating that protects the molten pools from the air so that a strong joint can be made. MIG welding uses a flux-core wire, while brazing rods are typically coated with flux.
Knowing the differences and similarities will better help you to understand which one you would need to use for a certain project. Next, we will go over the advantages that MIG welding and brazing have.
The Advantages and Disadvantages of MIG Welding
Most people would agree that MIG welding and brazing are not better than the other, necessarily, they just work better for different types of projects.
With that being said, each have their very own specific advantages that should be noted in case you are ever stuck deciding which technique you should use to join metal together.
Pros of MIG Welding
The advantages that come with MIG welding include:
- MIG welding is easy to learn. Compared to other types of welding, MIG welding only takes less than a day to learn.
- The process is fast. Since the filler wire is continuously fed through the gun, you do not have to stop constantly to change filler rods or clean the weld the second the heat is removed.
- The end result is a strong and neat weld. Since the fusion process takes place during MIG welding, the weld is very strong because the metals are fused together rather than being almost glued to each other, like with brazing. MIG welding also allows for great visibility where you can easily see the molten pool, which makes for a neat weld.
- It is a clean process. The shielding gas from the flux filler wire prevents most of the splatter that comes with other types of welding. It is also not required to scrub the weld as much as possible or chip away unwanted shards while the molten pool is still extremely hot.
- MIG welding is versatile. Many manufacturing companies use MIG welders for their products, but it is also common for many people to have MIG welders at their homes. This means that you can use MIG welder for big, intricate jobs and little home projects, whether it be repairs or metal crafts.
- The process is easy and fast to complete. With the continuously fed filler wire, fast learning process, and the advantage of not having to clean the weld so often, MIG welding makes doing jobs very simple and quick!
Some of the disadvantages for MIG welding are very minor but are things to be considered when thinking about MIG welding.
Cons of MIG Welding
The disadvantages for MIG welding include:
- It can be expensive. A MIG welder can cost a good amount of money, especially if you are looking to buy one of the best welders. There are also other pieces of equipment that will need to be replaced frequently, which can be expensive after a while. These other pieces of equipment include:
- Replacement tips and nozzles
- The molten pools cool very quickly. This may seem like an advantage, but if the molten pool cools too quickly when a mistake has been made, it will become difficult to correct.
- This process cannot be used on very thick metals. The fusion process is more difficult to complete with very thick metals. It is best to used thinner metals.
Now that we know everything that comes with MIG welding, it is time to look deeper into blazing and the advantages and disadvantages that can come with it.
The Advantages and Disadvantages of Brazing
Just like with MIG welding, brazing is an excellent and useful skill to know if you are looking to join pieces of metal together.
The Pros of Brazing
The advantages for brazing include:
- Different types of metals can be joined together. This just makes it easy to prepare your working materials. With brazing, it is not necessary to make absolutely sure that your metal alloys are the same to make a strong joint.
- The protective metal coating on the parent material will not be compromised with brazing. Since the temperatures with brazing are much lower than MIG welding, brazing causes minimal change and damage to the parent material.
- There is no need for a secondary finisher. The joint that is made with brazing is clean, with barely any ridges and shards that need to be chipped off. It is not necessary to do anything t the joint after it is completed.
- Brazing is economical. The only things required for brazing are the torches and filler rods. There is no expensive equipment or multiple parts that need to be replaced frequently.
- Brazed joints are mostly corrosion resistant. The joints made with brazing will not rust in the elements.
- Pipes and other thin pieces of metal that cannot be joined using welding can be achieved with brazing. This all goes back to being ablet o use different materials with brazing.
There are plenty of good things that come with brazing, and it can also be a very easy process to learn. There are also some downsides that come with brazing that you should know about before using brazing to join metal together.
The Cons of Brazing
Here are the disadvantages that come with blazing:
- High temperatures can ruin the joints. Since the melting points for the metal alloys that are used for the filler rods are much lower, any joints that are caught in extremely high temperatures could begin to melt.
- The color of the joints usually do not match the parent material. This is due to the filler rods usually being a different type of metal than the parent material so that it will melt without melting the parent material.
- Brazing provides weaker joints than MIG welding joints. Since brazing works mostly like a glue to combine pieces of metal, the joints are much weaker than with MIG welding.
Both advantages and disadvantages are things to always keep in mind before using any type of process.
In conclusion, MIG welding and brazing are two different types of techniques that are used to combine pieces of metal. While neither is better than the other, there are a few differences.
Here are the differences between MIG welding and brazing:
- The process of making the weld
- The temperatures used to make the weld
- The types of materials that are used
- How the contaminants react to the different temperatures used
- The welds look different.
- The applications for each are different.
While they are completely different processes there are also similarities, advantages and disadvantages that come with both of them. It is always important to do a little digging to find out which method is the best one to use for you.