How to Choose the Right Current in Stick Welding

  • By: Monica Shulz

Do you have a welding project coming up? You must know how to determine the right current or amperage setting for successful arc welding.

No need to worry about it though for it is nowhere near rocket science. Keep scrolling, and I will explain everything you need to know about the appropriate current setting.

What are the steps involved?

Instead of going the complex route of explaining the process, in this video, I adopted a much simpler approach that is both easy-to-follow and easy-to-understand.

Here is what you can do to make the correct determination of your stick welding current.

Replicate The Welded Part

To demonstrate and compare different electrode performances under varying currents, find a piece of metal of similar thickness with the part you wish to arc weld.

You will use this sheet of metal to make several welds using the different electrode types under different currents and observe the varying outcomes.

Choose The Best Electrode

The correct arc welding amperage and current depends on among other things the type of electrode used. The electrodes vary in diameter, welding position, and amperage range. The two major classifications of electrodes are the Rutile Coated electrodes and the base Coated electrodes.

The Rutile Coated Fincord Electrode used in this video has a diameter of 2.5mm, its preferable welding current is alternating current (AC) but if you decide to go with direct current (DC), use electrode negative connection, takes all welding positions except vertical down, and its range of recommended welding current starts from 65 Amperes with a maximum of 90 Amperes

On the other hand, the Base Coated Spezia Electrode has a diameter of 2.5mm, uses direct current (DC) electrode positive, takes all welding positions except vertical down, and its recommended welding current ranges from 59 Amperes to 95 Amperes.

Usually, Rutile Coated electrodes require more current than the same Base Coated electrodes.

Rutile Coated Electrode Negative 65 Amperes

This is the first weld we are going to make. From closer observation, it is clear the weld puddle is quite cold, the metal spreads rather poorly on the details, and the welding process is too slow.

It is also plainly noticeable that the arc burns dimly. That means it is unstable and constantly moving from side to side while burning, affecting the outlook of the seam. After cleaning the weld, you will notice that the seam’s form is incorrect; it is extremely narrow and high.

Furthermore, on the border between the weld and the base metal, there are some visible dark spots in form of small holes. That signifies poor fusion between the weld and the base metal.

Rutile Coated Electrode Negative 78 Amperes

With these electrodes, the liquid metal spreads better on the details, welding is faster, and the arc is more stable hence deeper penetration. Once you have made your weld, properly clean the slag and then keenly inspect the weld.

You will notice that the weld has a flat top and is wider than in the previous case of 65 Amperes. There is visibly no evidence of poor fusion between the weld and the base metal.

This would be the most appropriate welding current, but I would suggest adding about 5 to 7 Amperes for the best outcomes.

Rutile Coated Electrode Negative 95 Amperes

Making a weld under this current results in a few observations. First, the weld puddle is very fluid hence quite difficult to manage. Secondly, the metal excessively spreads over the surface, and quite a lot of large and small weld spatters are produced around the weld. Welding using this current is very fast, and the arc is extremely bright.

Proceed to clean over the slag and closely inspect the weld. What do you notice? First off, the width of the weld is more than necessary. What’s more, the weld’s top is excessively flat. There is also a huge amount of weld spatters all around the weld, which is not typical for rutile electrodes.

Base Coated Electrode Positive 50 Amperes

Switching gears now to base coated electrodes under 50 Amperes produces the following outcomes: the burning of the arc is not very bright, the liquid metal spreads rather poorly, and the weld has a narrow and high shape.

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Notice the appearance of the slag produced. It differs sharply from a slag produced with a rutile electrode. It is a lot denser, more fragile, and more difficult to clean than a slag made with a rutile electrode. You will require much more time to clean up the weld.

The shape of the seam is similar to the seam welded by rutile electrodes. It is too narrow and high meaning that the current is not enough.

Base Coated Electrode Positive 73 Amperes

I would confidently term this the optimal welding current. Why? Because the metal puddle is well managed, welding is relatively fast and produces low spatters, and the liquid metal spreads well on the plate.

That means it lets you operate the electrode without the slag running much ahead or behind the arc. It, therefore, covers the entire welded scene. This helps to protect the welded metal from the influence of air.

Pay attention to the final piece of the weld. The defects are more likely to occur at the beginning and the end of the welding. Clean the slag and observe the changes. The seam has a regular geometric shape with a flat top and a smooth transition to the base metal.

This form of a weld is obtained through a proper combination of different factors, including the:

  • Welding current
  • Welding speed
  • Electrode slope
  • Length of arc

Base Coated Electrode Positive 90 Amperes

With this current, the puddle is practically difficult to control because the liquid metal instantly spreads in all directions. This further makes electrode manipulation difficult. It becomes rather challenging to achieve identical width and height over the entire length of the weld.

Moreover, looking at the slag covering, you notice several gaps and discontinuities that ultimately lead to defects in the welded piece. Note that because of the high current value, the electrodes have to move more quickly hence affecting the weld’s uniformity. Narrow sections can be seen alternating with broader ones.

What Is The Right Current In Stick Welding

The best range between 72 Amperes and 78 Amperes preferably with a base coated electrode.

In conclusion, therefore, welds of insufficient currents have a sharp contrast to welds of average currents and high currents. Using extremely low or extremely high currents results in crooked welds that aren’t so appealing.

If you want look at videos of the steps above, please watch the youtube video below from Oleg Suvorov. If you like his video, please go to his channel also to get more videos such as the one below.

Photo by Oleg Suvorov / CC BY 3.0