How to choose a good welding machine?

Welding is the manual (MMA/TIG) or semi-automatic (MIG/MAG) process that allows two pieces of metal to be permanently joined into a single joint.

There are various types of welding machines and welding processes that are more or less suitable depending on how you work if you are a DIY enthusiast or a skilled worker who works in a shipyard. Basically, they do the same thing but with different methods. How can we choose a welding machine that suits our needs?

Advantages and disadvantages of coated electrode welding

It is the most widespread method because it is used by hobbyists and is among the cheapest and easiest to use, even for those approaching the world of welding for the first time.

To begin welding with electrodes, all you need is an inverter welding machine, electrode holder clamp and ground clamp, and a package of coated electrodes.

This process is versatile because with the advancement of technology welding generators have been smaller and lighter, allowing them to be moved even in places difficult to access.

Welding with coated electrode does not require shielding gas because the mix of minerals that covers the core of the electrode during fusion creates an oxygen-free atmosphere rich in deoxidizing gases, which protects the weld pool and deposits a "coat" of protection on the weld bead called slag.

The appearance of the weld bead created by the coated electrode process is not aesthetically pleasing compared to other welding methods, but it does have its advantages. We will discuss this issue later and we will try to answer the question: which electrode welding machine should you choose?

Advantages and disadvantages of MIG/MAG continuous wire welding?

It is the most widespread process in carpentry at industrial level, but it is also used at hobbyist level.

This welding method has many advantages over other processes.

One of the most appreciated qualities of continuous wire welding is that this welding method makes it possible to weld for a long period of time without having to interrupt the work process to reequip the welding machine, unlike with coated electrodes during MMA welding.

Continuous wire welding makes it easy to weld pieces with a large gap between them, acting as a filler as well as a weld.

The weld bead is aesthetically pleasing and quite clean with few spots, obviously if the welding parameters and shielding gas supply have been set correctly.

If flux-cored wire (no gas) is used, the welding spots increase, similar to coated electrode welding. At the end of the welding process, the slag must be cleaned before the next welding. To obtain good results with flux-cored wire, it is recommended to use it on a material more than 2 mm thick, otherwise the risk of piercing the base material is very high! Are you wondering how to choose a MIG/MAG flux cored wire welding machine?

TIG welding is the process that undoubtedly makes the weld bead look better than all other processes, because it does not produce any slag, since it is easily controlled thanks to the stability of the arc.

TIG welding is the most complicated process because it is usually performed with both hands, one to move and direct the TIG torch that delivers the welding arc and protective gas, and the other to place the rod of filler material in the welding pool to give strength and structure to the weld.

TIG welding is great when working on thin parts or on parts that do not need to be finished or painted at the end of welding. Some types of high-end TIG welding machines are also suitable for welding electrodes with MMA cellulosic coating.

HOW DO YOU CHOOSE A WELDING MACHINE?

The most important question to ask to avoid making a mistake is how to choose a welding machine that is right for you. What process will you use? What material do you want to weld? How much do you have to weld? What thickness are you going to work on?

Which electrode welding machine should you choose?

How to choose an MMA welding machine? The first thing to consider is the type of coated electrode (basic, rutile, acid, cellulosic) which you have to use to weld correctly.

This factor will help us choose between the various types of welding machines available on the market. A welding generator with a more or less high vacuum voltage facilitates ignition and maintenance of the welding arc of the electrodes being used.

Next, you have to consider the electrode thickness, and it will be easier to choose a welding machine which develops a more or less high amperage. This factor will help you choose a welding machine which meets your needs.

Another parameter that will help you understand which electrode to choose is the work cycle, which is the welding machine’s ability to maintain a given current for 10 minutes at a temperature required by the standard at 40 degrees ambient. Normally, the work cycle is the factor that influences the price of a welding generator the most, and it is the difference between professional welders and hobbyists.

Obviously, if you work at high amperages, the work cycle is reduced.

It is important to remember that the new types of welding machines have systems that help the operator do the job more easily

-Arc-force: voltage compensation to prevent the welding arc from extinguishing when, by mistake, the electrode moves too far away from the base metal.

-Hot-start: adjustable voltage peak to facilitate the ignition of the most difficult electrodes.

-Anti-stick: system that stops the welding machine when the electrode sticks to the base material, preventing the electrode from becoming unusable and burning.

-PFC: prevents absorption peaks from the power supply network, to better use the full power of the welding machine even with the standard 3kw power of the domestic network.

How to choose a MIG/MAG welding machine?

As mentioned above, the choice of the welding machine depends on how you are going to use it.

For continuous wire welding machines, there are various parameters to evaluate, in addition to the work cycle and the maximum amperage that the generator can handle, and the power supply available.

First of all, the thickness of the pieces that you are going to weld is a key factor, the greater the thickness, the greater the diameter of the wire.

One element distinguishing the various types of continuous wire welding machines is the wire roller unit, which may be supplied with 2 or 4 rollers.

Wire roller units with 4 rollers have more power and a better grip on the wire. Generators that are equipped with 4-roller units can normally handle large wire coils and are great for thinner wires. The 4-roller units guarantee a regular supply with MIG/MAG torches longer than 3 meters even with soft wires and therefore more difficult to pull, such as 0.8 mm aluminum wire. They commonly have a high working cycle for intensive use.

For optimum results, the correct shielding gas must be purchased according to the material that you are going to weld

Mixture (80%Ar 20%Co2) for iron, mixture (98%Ar 2%Co2) for stainless steel, Argon for aluminum.

How to choose a TIG welding machine?

The most important factor before proceeding with the purchase of a TIG welding machine is undoubtedly the material that you are going to weld.

If you are working with soft iron and stainless steel, a DC (direct current) generator is enough. If you also want to weld aluminum, the generator must produce AC (alternate current). Welding machines capable of producing AC/DC are not cheap, as they fall into the semi-professional or professional category.

Having said this, the choice of a TIG generator is quite simple, also depending on the type of control panel you prefer to have. A more complete control panel allows you to set more specific parameters (e.g., slope-up and slope-down, pre-gas, post-gas, pulsed, spot time, etc.) and consequently you can weld materials that have a thickness in the order of a tenth of a millimeter, which is normally intended for more experienced operators or TIG professionals with professional welders. Otherwise, you can buy a simpler welding machine where you only need to set the main parameters.

Also, do not underestimate the work cycle and maximum amperage that the generator produces, but the choice will vary based on your needs.

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