An Easy Guide to Welding Joints, Including When to Use Them

Following our look at different types of welds, let’s take a look at joints!

What is a welding joint?

A welding joint is the point where two or more workpieces are to be “welded” together. Most commonly, these are the material edge.

How many types of welding joints are there?

There are five main types of weld joints used in welding today. Each has their own purpose and advantages in a given job. They are as follows:

  • Tee joint: Exactly as the name suggests, a tee joint weld is two pieces of metal (or plastic), that meet to form a ’T’. This is usually at 90 degrees to each other. Common weld types are fillet or plug.
  • Butt joint: A butt joint consists of 2 pieces of the same thickness, meeting end to end. Resulting in them “butting up” to each other, forming a single flat sheet. Common weld types are groove or fillet.
  • Lap joint: A lap joint is two sheets of different thickness overlapping horizontally. This joing is usually used where a butt joint won’t provide enough strength. Common weld type is fillet.
  • Corner joint: Like a tee joint, a corner joint consists of two pieces meeting. But, they form an ‘L’ shape instead of a tee. Common weld types are fillet and groove.
  • Edge joint: Where the edges of two flat surfaces align, with the edges then capped with a weld. Common weld types are fillet, groove, and bevel.
Aluminium TIG Welded Box
TIG welded aluminium box by Josh Maynard.

Which is the strongest welding joint?

It’s commonly thought that a corner joint or tee joint are the strongest. Especially when combined with a penetrative groove type weld. It may not be appropriate for all jobs, so you are always best to check depending on each situation.

Which is the weakest welding joint?

An edge joint is the weakest type of weld join, so isn’t suitable for load-bearing jobs. Instead, it’s ideal for reinforcing metal and replacing worn and damaged metal.


Each type of welding joint has its advantages and disadvantages in different situations. Working environment, material characteristics and welder skill are all factors. A successful weld is the culmination of the right preparation and equipment too!
So do plenty of research to ensure the job is done once right, and avoid costly errors!
Check out this article from World-renowned knowledge centre TWI.

Note: Proper safety precautions are vital with all types of welding. This can be a dangerous hobby or career. Always wear a trusted welding helmet to protect your eyes, and appropriate protective clothing. Including welding boots, overalls, and tie back your hair.
Welding can cause respiratory diseases and cancer. Ensure ample fume extraction is available for a safe and comfortable working environment. Read more about fume extraction requirements here.

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