How Far Apart Should Spot Welds Be?

There are many factors to consider when welding, and one of the most important is the distance between spot welds. It’s easy enough for a professional welder to know how far apart they should be, but what about beginners? 

When it comes to spot welds, the general rule of thumb is that they should be 2.5 to 3 centimeters apart and roughly 10% of the exposed length. Experienced welders know not to go any closer than 1mm, but beginners may find this extremely difficult to do.

For those just starting out in welding, it can be confusing knowing how close or far away from each other these welds need to be in order to create a strong bond. Keep reading to learn exactly how you can make the perfect distanced spot welds.

Why Do Spot Welds Need to Be Apart?

Spot welds need to be apart to avoid cracking on the weld and for long-term durability. Spot welds that are far apart hold up better over time and produce stronger materials.

For starters, when you weld metal, heat is produced as a byproduct. If spot welds are too close together, that heat will increase exponentially and cause cracks between the joints. 

This is due to fusion defects like pinning or slumping – this kind of defect happens when layers of metal can’t bond tightly together. Generally speaking, spot welds should be spaced out 2-3 centimeters apart from one another as well as 10% of the length of what’s being welded. 

However, there are more complex factors at play here: some materials create more heat than others so personal preference will vary accordingly. Besides spacing out spots to avoid fusion defects, it’s important to keep them spaced apart for structural integrity.

Spot welds should never be directly next to each other because when they are, the joint will weaken and eventually break under stress. Your goal is to create a strong bond that can withstand pressure and heat without falling apart or breaking up into smaller pieces.

How Big Should Weld Spots Be?

Spot welds should have a diameter of about 0.003 inches, which in layman’s terms is just over 3/16 inches. Regardless of the material being welded, it should never be smaller than 3/16th inch and 1/4th inch for thick materials.

It’s not just the spacing between welds but the size of the individual spot welds themselves that are important. 

Seam or penetration welding is more successful when there is a diameter between 3/16 to 1/4 inch.

This is because, in thinner spots, there isn’t enough length for the heat to be contained and penetrate through the fluid metal before cooling down.

What Is the Best Method for Separating Spot Welds?

If you’re looking to separate the join between sheets of metal, it is best to use dual cutters. When using a screw extractor, pneumatic or manual on materials between 3/16 of an inch and 1/4 of an inch, a center punched mark should be made first before drilling the hole. 

Once drilled through two sheets with a hole saw (3/16″ if less than 1/2″) and pulled out with a right-angle connector.

The solution will show if they were successfully separated or not. This method yields a 100% success rate as long as you are careful enough when inserting the extractor into the hole.

You shouldn’t spot weld at home if you are an inexperienced welder for the following reasons:

  • The tools you need are expensive and if you don’t understand how to use them properly, then it could result in injury or property damage.
  • There are many ways that spot welding can go wrong even when you know exactly what you’re doing. You’ll need to consider different variables involved in the process, like where to make up for any lack of air pressure.
  • Even if a new welder has had some success at their own workplace with an experienced mentor, they will not have the same support at home.

If you believe you have the experience and tools needed, you should practice with scrap metal first and do it in a safe environment.

How Do You Get Rid of Spot Welds?

The best way to get rid of spot welds is with a screw extractor. Enlist the help of a friend, family member, or neighbor to stay safe. 

If this is not possible, use an air-powered pneumatic drill and other industrial gauge tools to cut out the sheet metal and welders pliers to remove old spot welds (only for material 3/16″ or thinner).

If you need to get rid of spot welds, here are a few steps you need to follow:

  • Identify the spot welds that need to be removed using a screw extractor, an air-powered pneumatic drill, or other industrial gauge tools. 
  • Use welder pliers to remove the old spot welds (only for material 3/16″ or thinner). 
  • Apply heat with an acetylene torch (just a few seconds) if you’re getting rid of welds on heavy materials. The heat will soften the adhesive joining them together and allow them to be pushed apart without any force applied by hand. 

You want to remove your spot welds if your welds are not tight, you want to change material (e.g., welding steel onto aluminum), or if the surface is going to be painted over and needs priming.

A spot weld that is not tight will cause problems by either tearing the material or not holding it in place.  

Do Spot Welds Need to Pass Inspection?

In all fabrication processes, spot welds or weld joints should be inspected under varying degrees of magnification. This is to ensure that joints are properly executed and free from defects.

You could find defects in:

  • Design
  • Materials
  • Mechanical condition
  • Welding conditions
  • Procedures

Inspections can also identify subtle variations in shielding gas flow rates into the base metal, which may not have been apparent at the time of production.

How Are Spot Welds Measured?

Spot welds are measured differently depending on the material being welded and what kind of projection is going to be made. It’s common to see spot welds measured in inches or centimeters. 

For example, a spot weld on steel might be measured from outside edge to outside edge with round head tooling or in inches for flat head tooling. 

However, when it comes to copper, measurements can range anywhere from millimeters up to centimeters per side.

Keeping Spot Welds Accurate

Keep your spot welds far enough apart so that they don’t experience any cracking over time. The closer they are, the more susceptible they will be to damage. As long as you are familiar with how you should be creating spot welds, your next project should hold together just fine.

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