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Overlap Welding – 4 Main Causes & How To Prevent It

The welding process is introduced to avoid defects, but sometimes various defects occur. This happens due to some manual defaults or inexperienced individuals. Overlap welding is one of the most common defects arising in welding.

It is not a very harmful defect that weakens the joint but destroys the weld’s beauty and cleanness. In this article, we will discuss the causes, effects, and solutions. To get a deeper insight, keep reading on.

What Is Welding Overlap?

Welding is done by fusing the base metal and the filler metal, but sometimes, it doesn’t go as planned. The filler metal exceeds its limit and doesn’t fuse with the base metal properly, due to which it overflows.

It appears like a weld pool just like a swimming pool where water overflows when the limit exceeds. This overflow of weldment is known as overlap. This overlapping occurs when the weldment protrudes the weld toe or root. This leads to discontinuity or gap.

4 Main Causes Of Overlapping & How To Prevent It

Overlapping is not considered a top defect but affects the weld’s quality. No matter how fragile it is, no welder would want to have it. Therefore, you must know the four main causes and their remedies to not get it to lower your weld quality.

1. Amperage

Amperage is the most usual cause of overlapping. If amperage is not set right as it is required during the weld, it will cause the overflow of filler metal. The amperage can be set too high than required in this case.

To avoid this condition always make sure to ask it an experienced welder or consult a chart. After asking and setting your amperage, try it on a rough metal so that you won’t ruin the actual piece. If you see the overlapping on the trial metal piece occurring, keep lowering the amperage until overlapping doesn’t happen again. After setting the amperage, move to the workpiece.

2. Travel Speed

Overlapping also occurs due to a very fast travel speed. It is due to the deposition of the weld pool that keeps accumulating. So if your travel speed is less than required it’ll most possibly accumulate and cause an overlap. This can be easily solved by enhancing the travel speed but make sure to not exceed the limit. It’ll also be problematic. Find a moderate speed for your weld to avoid this overlapping.

3. Electrode Selection & Usage

Proper electrode selection is necessary to avoid overlapping. If you ignore this, it’ll cause your weld a hefty amount of damage. You must know the angle and size of your electrode to avoid this.

Electrode Angle

Even the angle of filler metal is essential to avoid overlapping. If the angle is not correct, the weld pool fails to penetrate enough and causes overlap. This is because of the improper amount of weld that stays on both sides and makes a crown. So always ensure your electrode angle before welding.

Electrode Size

The electrode is the filler that will be fusing base metal. So it is clear that the amount of the amount or size of the electrode decides the weld. If the electrode is large, there will be more filler metal overflowing eventually causing an overlap. But if the size of the electrode is according to the base metal. This never happens. So you must use the proper size of the electrode by asking an experienced welder or by consulting a chart.

4. Welding Technique

The welding technique contributes a lot to this process. Metal pre-preparation is inevitable if you don’t want any defect occurring. So always ensure the proper alignment of the edge, and cleaning of base metal to prevent any bumps in the weldment process.

How To Avoid Overlap Welding

You can avoid overlapping by following the measures below.

1. Utilizing Tiny Electrodes

The risk of overlapping decreases to a great extent by using small electrodes than larger ones. As it won’t let the weld pool flow eventually preventing the overlapping.

2. Utilizing the Appropriate Amount of Current

You must be using an appropriate amount of current (AC or DC) to prevent overlapping. If the electrode glows too shiny, it represents that your current is too high. You must decrease it to the proper limit as it’s necessary to have a precise weld.

3. Clean the Base Metal

Cleaning of the base metal is the most necessary measure to prevent any kind of weldment defect. It applies to the same for overlapping. As it helps in the removal of debris and intricate particles from the base metal and doesn’t make gaps left.

4. Keep a Moderate Speed of Travel

If the travel speed is not moderate, it’ll cause serious defects, including porosity due to the trapping of gases and undercutting. The travel speed must not be too slow to melt the base metal or not too high to run you into trouble. Make the travel speed moderate according to your base metal.

5. Learn how to handle Electrodes Correctly

This method depends on your work experience. All welders have different methods according to their ease. So you have to adopt yours which will come only by practice. See how the professionals do it and make your method which is in your comfort zone.

How To Fix Welding Overlap

Welding overlap is not such a big defect to be overwhelmed. It can be easily corrected once you are done with your welding. You can easily clean it by grinding it up from the toes. You just have to ensure the joint stays intact during the cleaning process. When you do it, it cleans off the extra filler metal that is accumulated at the toes. After cleaning this accumulation, polish the surface for smoothing, and you’re all set.


Overlapping is a frequent defect occurring due to various reasons and causes. But it can be easily tackled with some practices and ways. You just have to be patient and cautious while welding. As it can be easily removed once the weld is done without harming the joint. We have described the causes and remedies above but if you still got some queries, you can ask us in the comment section below.

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