The Battle of AC vs DC Welding: Which One Is The Best?

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Which one is more STABLE, Ac or Dc welding?

It’s a question that drives you nuts, right?

Can’t BLAME you!

Welding is a vast field. And most probably you are a starter. No wonder, the term AC/DC looks like rocket science to you.

Don’t you just hate it when it’s puzzling?

Well, let me help you. AC is basic welding, used brazing and Carbon Arc welding. It’s upgraded into DC power, improving the ease of welding first.

Still not convinced?

Keep reading, and you’ll find out the arc welding basics stuffs about industrial equipment and the difference between ac vs dc welding.

Related: Can You Weld a Magnet: Yes It’s Possible!

Difference between AC and DC welding machine: An in-depth comparison

dc welding is preferred over ac welding because of


Welding is the joining or connecting of two or more metal parts normally by melting them together. Like any electrical current, a welding arc has a polarity, designed with a positive and negative pole.

I know you are getting bored and disturbed why I am touching this technical term like polarity, but This Welding Arc Polarity is closely related to Ac and dc welding.

So what is Welding Arc Polarity?

Polarity has a significant effect and the strength of a weld. Meanwhile, Electrode-positive, also known as reverse polarity causes a penetration then electrode-negative polarity (reserve). So usually there are two types of polarity.

  • welding reverse polarity
  • welding straight polarity

Straight and reverse polarity is so common term in Arc welding.

Get it?

In most of the time, DC is the preferred welding polarity. Now let’s see what the difference between AC vs DC welding machine.

In a hurry? Check out the quick comparison table then.

PointAC Welding MachineDc Welding Machine
SizeSmall in SizeLarger in Size
WeightLight in Weight Heavy in Weight
Price RangeReasonablePricey
Arc Blow Comparatively Easy Difficult to Control
Operating Cost CheaperHigher
Voltage drop rateLessHigh
Energy consumption3 to 4 kWh6 to 10 kWh

1. Overview of DC welding

DC welding

“A great option for beginners learning the welding”

DC refers to direct Current, a process where the charge travels in only one direction and returning a constant polarity. As I mention earlier, in welding there are mainly two electrode connections. These are:

  • Current electrode positive (direct)
  • Current electrode negative (direct)

Hence, Electrode negative or straight (DCEN) is faster in its process, as well as the melt-off of the electrode is relatively quick.

So have we got that straight?

The straight current produces less heat than the positive electrode. That’s why it is used widely on thinner substrates.

What is the dc welding machine working principle?

In DC reverse polarity method, the electrode is positive; on the other hand, current flows from its workpiece to the electrode.

Advantages of DC Welding

  • Less splatter.
  • Easy to start.
  • Less sticking/ outages.
  • Better with vertical welding.
  • Leave a smoother arc.
  • Great for thinner metals.

Downsides of DC Welding

  • Not well enough to fix arc blow.
  • More expensive.
  • It’s doesn’t work well for high-intensity heat.

2. Overview of AC welding

AC refers to Alternating Current where the electric charge moves in one direction half of the time and then for the other half flows in the opposite direction.

Can’t understand anything?

In plain words, the flow of electrons always keeps switching directions and going back and forth. Hence, it can even change its polarity 120 times; yes it’s for per second.

Now let’s be honest.

AC should be a secondary CHOICE in welding. Of course, there are a few instances where AC welding would be preferred. For example, entry-level, low cost, machines sometimes run only AC power.

Let’s see the advantages and disadvantages of ac welding machine.

Advantages of AC welding

  • Magnetized materials
  • comes at affordable price
  • For use on aluminum
  • Highly portable

Disadvantages of AC welding

  • Creates more spatter
  • Don’t expect smooth cut as DC

Key differences between AC vs DC welding and how they impact your work

There are some big differences that have a big impact on whether the Ac or dc welding is right for you.

First, let’s talk about size. AC machines are small in size. As a result, weight is also pretty light. On the other hand, DC is relatively larger, weight is also pretty heavy.

Now come to Voltage drop. In A.C welding machine, the Voltage drop in A.C. is less, therefore can be used at large distances. On the contrary, the Voltage drop of D.c is relatively higher and can be used at a short distance.

Wait, there is much more.

Where DC has a higher operating cost, AC machine is comparatively affordable.  Meanwhile, less electric energy consumption need for per kg of metal deposited on AC welding.

The uses and applications make a huge difference between the two. With the A.C. power supply, only a few machines can be used which need low power factors.

Types of welding using AC

  1. TIG welding aluminum
  2. In shipbuilding
  3. Downhand on heavy plate

On the other hand, DC can be used anywhere with machine engine driven D.C. generator or even by rectified A.C. supply.

See the difference?

In short, it supports a good amount of machine and more versatile. Have a look at the Types of welding using DC:

  1. Cast iron.
  2. Overhead.
  3. Vertical.
  4. Sheet metal.
  5. Rivets.
  6. Heavy aluminum.
  7. Arc bronze rod.
  8. Low hydrogen.

The last one but not least, the maintenance of AC welding is more economical and easier than DC.

So which one is the best?

As we can see, both come with some particular areas where each one will be UNBEATABLE. So AC and DC welding are used for completing different tasks.

But yes, in most cases, DC welding machine is more advantageous compared to AC welding. Hence, in certain cases, classic AC will also be a better choice.

No matter what you choose, don’t forget to use the best welding gloves and protective gear like a welding helmet.

Which works better for a stable welding arc: AC or DC?

There are many factors that go into making a stable arc welding joint. The welding current’s magnitude and direction should be constant, and the electrode should be properly balanced. In AC welding, the magnitude of the current alternates, so it is not always constant. This can cause the arc to become unstable.

In DC welding, the direction of the current is always constant, so it is easy to stabilize the arc.

Can you do stick welding with AC and DC?

Stick welding is an arc welding process that uses a consumable electrode to create the weld. The electrode is a piece of metal that is connected to the welding machine and melted down to create the weld. Stick welding can be done using alternating current (ac) or direct current (dc).

Frequently Asked Questions (FAQs)

Question: Is MIG welding AC or DC?

Answer: Well Yes, technically ac source can be used for MIG welding and also is cheaper than dc source.

Question: Does the stick welding stainless steel ac or dc?

Answer: DC stick welding ensures more advantages over AC when stick welding steel, including more stable and smoother arcs, easier starts, less spatter, and overhead welding.

Question: Do you use AC or DC to weld aluminum?

Answer: Ac is preferable for weld aluminum.


In conclusion, AC welding is better for general welding, while DC welding is better for welding metals with a high electrical resistance. If you’re not sure which type of welding to use, AC welding is a good place to start.