AC vs DC Welding: Differences, Pros, and Cons
The welding community has been seeing a good amount of expansion throughout the years. But not all of the users fancy welding certifications. For that reason, understanding the topic of AC vs DC welding can be a bit tricky.
However, no matter how much of a newbie you are, you can view the complete picture pretty easily after going through the in-depth information regarding the topic. And that is exactly what we plan to deliver through this article.
But what makes us capable of offering that? Well, we have used both the AC and DC welding devices thoroughly for years. And at this point, we know every single thing that makes them different. So, without further ado, let us dive right into the topic, shall we?
Allow us to start with the AC welding process. It refers to alternating current, and this current alternates from positive to negative. Basically, it does not remain stable. If you have a look at the waveform of this current, you will notice a wavy line.
This type of current is what most of the home outlets supplies to your devices. For that reason, it is possible to connect the welding devices directly to this current. There will be no need for any conversion, nor will there be any need for modifications.
What Does AC Welding Have to Offer?
AC welding is known for having many practical applications. The advantages that it has to offer make repairs easy in industrial settings. But what benefits are we talking about? Well, allow us to go through them, shall we?
Can Be Used on Workpieces with Magnetic Field
As you know by now, arc wandering is something that most welders are not okay with handling. But with AC welding devices, handling these types of scenarios becomes pretty easy. Arc wandering basically happens when there are magnetic currents. It makes the arc get out of alignment with the electrode.
Unlike the other types of welding devices, the AC welding ones are not susceptible to this issue. And this capability can surely come in handy when you plan to make a repair on heavy machinery. Construction machines, forklifts, and logging equipment will become easy to work with.
Operates When 220 Current Is Not Available
When there are limited power options available, most of the other welding devices might not work. But you will be capable of using AC buzz box welding devices even when the 220 current options are unavailable. That is why it is a go-to option for a small garage or home shop.
Tig Welding Aluminum
Aluminum materials are usually coated with a layer of aluminum oxide. Even though the layer is comparatively thin, it can interfere with the welding bead. That makes the other welding devices pretty much useless on the surface.
However, the quick polarity jump of the AC welding devices will offer you a scrubbing action. This will let you break up the layer of aluminum oxide and work on the surface efficiently. It will also be possible to keep the joint from contamination.
Drawbacks of AC Welding
When it comes to preferred polarity, AC welding is not really the first choice for most welders. Usually, it does not make the workpiece look pretty. But that is not all; there are some common disadvantages of AC welding. And they are:
One of the most common drawbacks of AC welding is the loss of arc. It happens because the current is fluctuating between each of the poles. And the arcs need to restart each time the current flows from positive to negative.
In some scenarios, the arc will not restart itself. That means you would need to do it manually. And that is not a favorable situation because it creates a breaking point in the weld. That point can make the weld weak. In fact, you might have to break the weld and restart from the beginning if that happens.
As we have mentioned above, AC welding can not make the workpiece look pretty. Wondering why is that? Well, there will be splatters when you are working with the arc. These splatters will form tiny bits of debris on the spot. It happens because of the fluctuating current.
To make the workpiece a little bit good-looking, you would need to grind the splatter manually after working it. That can make the whole welding task feel a bit troublesome and time-consuming. If you want to know why spatter happens and what to do to reduce it, here's an article we wrote. Also, there are anti spatter sprays available.
As the name suggests, these welding devices will use direct current. The current will flow through the electrode that will join two pieces of metals together. And if you look through the waveform of the current, you will not notice any wavy line. Instead, it will be straight, which makes the flow of current stable.
Basically, the current will not stop from one arc to another while going through the electrodes. The positive and the negative will maintain the same specific polarity. While the negative polarity will maintain the current flow from the device to the electrode, the positive will flow the current from the welder to the workpiece.
What Does DC Welding Have to Offer?
There are plenty of circumstances where the DC welding devices will get the most priority. In fact, when it comes to making welds pretty, the go-to pick will be DC welding instead of the other forms. But it has loads of other things to offer as well.
Applicable for Most of the Scenarios
DC welding can be used for most of the welding tasks. To illustrate, you can use the DC welding devices for chassis, large fuel tanks, tow hitches, and other large-scale projects. The reason behind DC welding being a perfect pick for these projects is the welding quality it can offer.
Unlike the AC welding devices, the DC will not produce that many splatters. That will offer you the ability to retain the overall looks of the project. You can get exceptionally smooth and aesthetically pleasing welds on surfaces. And as these do not leave that much splatter, intense clean-ups will not be necessary as well.
Less splatter directly translates to better welds. For that reason, DC welding devices are the go-to picks for welders for projects that require strong and long-lasting bonds. The non-changing polarity also means that you will not have to worry about changing the electrodes that much.
In fact, the welds that these devices offer will let the projects withstand the higher load, heavy pressure, and abuse. You can basically count on the weld to last for a prolonged time.
Drawbacks of DC Welding
Even though DC welding holds the ability to produce a clean and smooth-looking weld, it does have some drawbacks. In fact, some of the flaws of this welding process can make it hard to use in the applications where it shines the most. Nonetheless, let us go through each of the drawbacks briefly, shall we?
Requires Internal Transformer
As you know by now, the outlets will offer AC. And DC devices can not use AC at all. That brings a transformer to the equation. It will do the work of transforming the AC to DC and make the device operational. But this transformer adds complexity and additional weight to the DC welding devices.
The added complexity and weight will translate to higher costs. Also, to operate a DC welding device, a 220 volts circuit is necessary. It will also mean to set things up — you would need to rely on an electrician.
Magnetic currents that are present on the welding metal can pull the arc. That will make the arc misaligned with the electrode. As a result, there is a higher chance of the bead getting ruined. For that reason, whenever a project has a magnetic field, welders will opt for AC welding devices.
As the polarity flows and flips too fast from one electrode to another, arc blow is not a big problem for AC devices.
Unlike the other welding devices, DC ones will require a good amount of skills. That makes these non-beginner friendly. You would need to have a fair set of skills to get a proper weld out of these.
If you are serious about welding and want to use TIG or MIG, the DC device is for you. For that reason, you will notice most of the professionals are using DC welding devices.
Can You Use DC Rods in AC Welder?
No, it is not possible to use DC rods in an AC welder. You can not even do the opposite thing: use AC rods in a DC welder. However, if you have an AC/DC welder, you can use either of the two. But even in that case, you would need to adjust the machine accordingly.
The filter metals for each of the welding devices are different. There are a couple of conditions that vary significantly between the AC and DC devices. Therefore, you will be facing an absolute disaster if you use the wrong stick for the devices.
The main takeaway from AC vs DC welding is that each device is different and has its own benefits. One can produce clean and smooth welds, while the other can mitigate the arc blow. However, there are additional criteria too. So, we can not really state one is better than the other.