Tack Welding Vs Spot Welding – Know the Differences

In tack welding and spot welding, the welds that are created are very similar. The welds are small and do not run the full length of a seam or joint in the metal.

They are different welding processes that require different settings and skills, but what is the difference between the two?

Tack Welding

Tack welding is actually a method of joining two base metals together, and keeping those metals joined long enough for a true weld to be created. Because of this, you can say that tack welding is a temporary method of clamping two pieces of metal. The welds are never meant to hold for long periods of time.

When welders use a tack weld they create the welded clamps by doing a series of small welding bursts across the distance of the two base metals. Tack welding keeps the two base metals pulled together so they do not move as the final welding process is done.

If you were to see a problem with the joint of the two base metals a tack weld can be pulled off to allow you to realign or reposition the base metals. When a spot weld is created it is a permanent weld and you do not simply pull it off and then start again.

You perform the tack weld process using an MIG welding set-up just like you would use if you were about to spot weld.

Spot Welding

Spot welding is a permanent joining of two metals performed by applying heat and pressure to the seam the form of the metal when they are placed beside each other. The spot weld is small like a tack weld but it is designed to be a permanent fastener for the metal components.

Spot welds are primarily used with wire mesh, thinner sheet metal and welded wire mesh are being joined. It is a process that is used more than 5000 times during the construction of an auto body and frame.

Spot welding is used often when people are building metal furniture and some types of décor. Metal building components are often bonded together using the spot welds and electronic devices have a lot of spot welds on them holding pieces together.

Spot welding is a very quick welding process and it is very easy to do. This type of welding creates a secure bond between the metal items that are not easily broken or displaced.

An MIG welding process is used to perform the spot welding just like it is when you do a tack weld.

Spot welding VS tack Welding

Similarities

Spot welding and tack welding can both be completed using the standard equipment required for MIG welding processes.
Spot welding and tack welding create small welds that combine two pieces of material.
Spot welding and tack welding are both very quick to complete welding processes and they are both very easy to perform.

Differences

Spot welding is a permanent method of joining pieces together where tack welding is a temporary method of holding two pieces together.
Tack welds are made on all variety of base metals to hold them in position until the permanent weld can be made, but spot welding is primarily performed on thinner metals and smaller metal pieces.
Tack welds are easily pulled off if you need to reposition the metal pieces they are connecting, but spot welds are firmly in place and it takes a lot of grinding and work to remove a spot weld.
Tack welds do not have the same amount of strength that spot welds have and therefore they are not relied on for long periods of time.
Tack welds are not as neat or as aesthetically pleasing as a spot weld.
You would not use a tack weld process on sensitive items like electronics but spot welding is often performed on sensitive items.

Final Note

Tack welding and spot welding both have their places in the world of metal fabrication and they are very similar. Tack and spot welding are done mainly by more experienced welders who have a better understanding of the exact heat requirements, and speed of movement required to create these particular welds.

Last Updated on 2 years by Richard Boyer

Richard Boyer

Richard Boyer has been a professional welder for over 27 years of his life, and now he is a trainer and blogger providing critical information to anyone interested in welding. He is helping out both hobbyists, novice and professional welders to learn newer and better techniques. Read more about me

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