Describe What A Lap Joint Is In Oxy Fuel Welding.?

The lap joint is one of the most commonly used oxy fuel welding (OFW) techniques, and has been employed for decades to join two similar or dissimilar parts together. In an OFW lap joint, two overlapping plates are tied together, allowing a tight fit with minimum welding pass. Although this joint type is more commonly found in a variety of industries, ranging from automotive and fabrication to aerospace, it’s estimated that more than half of all OFW applications involve a lap joint.

This article provides a detailed overview of oxy fuel welding lap joints, including common achievements, processes and recommended applications.

What is a Lap Joint?

A lap joint is a type of welding joint that is created by laying two pieces of metal on top of each other and welding them together.

The most common type of lap joint is an oxy fuel joint, where an oxy fuel torch is used to create a strong bond between the metals. In oxy fuel welding, the metal is heated until it becomes malleable and can be joined together.

Benefits of Using a Lap Joint

The lap joint is one of the most common types of joints used in oxy fuel welding.

It is a strong joint that can be used to join two metal pieces securely. Additionally, the lap joint is relatively easy to learn and can be completed quickly.

Creating a Lap Joint with Oxy Fuel

When creating a lap joint with oxy fuel, the fuel gas is used to preheat the two pieces of metal that need to be joined. This softens the metal, which allows the two pieces to easily slide together when the flame is removed. Once the two pieces are in place, the welder applies a filler metal, typically a rod or stick of the same metal that is being welded, to help create a strong bond between the pieces.

Step 1: Prepare Your Materials

The first step in creating a lap joint is to properly prepare the materials you intend to weld together. The pieces should be cleaned with a wire brush or other abrasive tool to remove any oil or contaminants that could prevent a strong weld.

The pieces should also be inspected to ensure that they fit together without any gaps or other defects that could prevent a successful weld.

Step 2: Pre-heat the Materials

Before welding the two pieces together, you need to preheat the metals with an oxy fuel torch. It’s important to not overheat the metal, as this can cause it to warp or otherwise be damaged.

The optimal preheat temperature for most metals is around 1820°F (1000°C).

Step 3: Apply the Filler Metal

Once the two pieces are preheated, the welder should apply a filler metal. This is normally done with a stick or rod of the same metal that is being welded. The filler metal should be applied in short strokes, working your way up and down along the joint to ensure that it is completely filled.

Step 4: Cool the Joint

Finally, the joint needs to be cooled down. This can be done by quickly spray the joint with water or air to cool it down. After the joint is cool, it should be inspected to ensure that there are no weak points or other defects in the weld.


Lap joints are an essential part of oxy fuel welding and can be used to create strong bonds between two pieces of metal. A properly executed lap joint requires preparation, preheating, and applying a filler metal with the correct technique. With the right technique and careful attention to detail, oxy fuel welding can be used to create strong, reliable lap joints every time. Citations :https://www. welding-advisers. com/lap-joint. htmlhttps://www. hobartwelders. com/resources/oxy-fuel-welding-techniqueshttps://en. wikipedia. org/wiki/Welding_joint

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