What is the Best Way to Remove Tack Welds?

Tack welds are important in many welding operations. You use them to properly secure workpieces and prevent them from moving unnecessarily. Tack welds are easy to make and you use them to maintain the weld gap. However, not every part tack weld gets consumed after the welding process. Hence, it is necessary to remove excess heat tack welds for quality control.

Removing tack weld is important to improve product quality and increase customer satisfaction. As a tack welder, how can you go about this to achieve excellent results? Read on to find out what tack welds are about, their use in metal fabrication, and how to remove them after they’ve completed their purpose. 

What are Tack Welds and How they Work

Tack welds are small drops of welds that temporarily hold metal pieces in place before the main welding process. You can use tack welds alone or in addition to work-holding fixtures. This helps to properly align the workpiece and maintain the needed joint gap. Furthermore, these strong and tiny welds prevent unwanted shifting and vibration when welding the components. 

There are different techniques you can use to make tack welds. They include shielded metal arc welding, gas metal arc welding, and gas tungsten arc welding. The first step is to clean the workpieces using suitable agents. You then consistently feed in the wire electrode. Thereafter, create a small and controlled arc to form small weld beads in the desired location. 

Note that there are different types of tack welds in metal fabrication. The most common are standard, bridge, and hot tack welds. 

• The standard tack weld is small and is usually about ¼ inch in size. You use it mainly for repair and part assembly. 
• Bridge tack welds are longer and are ideal when there is a gap between the parts you are working with.
• Hot tack welds look like the bridge type. However, they are rougher and you use more filler materials.

Why Remove Tack Welds

As we’ve said, tack welds are temporary. Most times, you have to remove them if they do not become a part of the final weld joint. The following are some reasons you have to remove tack welds after welding or before you perform any finishing technique.

• Enhance Aesthetic Appeal

Tack welds when left alone can become exposed and visually unappealing in some instances. They create bumps and ridges that may increase surface roughness. This can be a turn-off for customers who want to make a purchase. For this reason, you should remove tack welds after it has served their purpose to enhance brand reputation.

• Reduce Material Thickness

Tack welds are excess materials that can increase the thickness of the workpiece. Furthermore, they add to the weight of the final part. Removing tack welds will reduce weight gain and the incidence of dimensional inaccuracies. This is important for automotive components where lightweight is key in improving fuel efficiency. 

• Improve Weld Quality

Tack welds can affect weld quality if they are not consumed during the final welding process. They can interfere during welding and prevent sufficient and consistent penetration. Furthermore, they increase the chances of creating different types of welding defects. Taking off tack welds reduces the risk of corrosion and increases structural strength.

• Ensure Part Fitment

Excess tack welds make it challenging for parts that need to be assembled or fitted into one another. These welds can create a barrier that makes assembling difficult. Furthermore, it can lead to damage if you try to force them to fit. 

What’s the Best Way to Remove Tack Welds

There are different techniques you can use to remove tack welds. They have their unique benefits and the type you use depends on your project requirements and the surface quality you want to achieve. Let’s look at some ways you can easily take off tack welds

Grinding 

A good way to remove excess tack welds is to use grinding wheels manually by placing them on a benchtop. These tools help to flatten the surface of the joint to give it a more refined look. Grinding provides total control to avoid removing too much or too little material. However, you should be careful because the abrasives may damage the base metal. 

Chipping

You can also use a welder chipping hammer to clear protruding rack welds. What the hammer does is break away excess material to create a flat surface. Chipping comes at a low cost and is not energy-intensive. However, you should use it for small tack welds that are easy to handle. 

Oxy-Acetylene Torch

Another ideal way to remove excess tack welds is the use of oxy-acetylene torch. This torch ignites a flame using a mixture of oxygen and acetylene. The heat generated is high enough to cut away parts of the protruding tack welds. Oxy-acetylene torch is versatile and suitable for many metals. You should be careful when using this torch because of the potential to create a large heat-affected zone (HAZ). 

Machining

Machining is another effective way to remove tack welds. There are various machining operations you can use including milling and turning. Your choice depends on the shape of the workpiece in question. This technique is accurate and does not compromise the quality of the surrounding material. The downsides are the cost and operator skill requirements. 

Plasma Cutters

The cutting tool used in plasma cutters is an electrically conductive gas. This gas heats a particular part of the tack weld to melt the excess portion out. Plasma cutters are fast and produce precise cuts. Additionally, they are safe and come with minimal heat-affected zones. However, plasma cutters only work with electrically conductive materials and small tack welds. 

Chemical Removal 

You can also remove excess tack welds chemically. Common chemicals include weld cleaning solutions or compatible acids. Chemical removal does not cause any form of mechanical damage to the workpiece. It is easy to apply and not labor intensive. However, you need to carry out the process in a ventilated environment to prevent work-related hazards. 

Dremel Tools

A dremel tool is another means you can use to remove excess tack welds. You attach suitable accessories to this tool which rotates at a high speed to polish and grind the tack weld. This tool is easy to use and produces a good finish. The limitation of using dremel tools lies in the frequent replacement of cutting discs because they wear off with time. 

Best Practices for Removing Tack Welds

Though removing tack welds is relatively straightforward, there are some considerations you should keep in mind to avoid mistakes. The following are common best practices in tack weld removal 

• Clean the surface of the workpiece properly to avoid contamination.
• Remove the tack welds immediately after the welding operation. 
• Use appropriate tack weld removal techniques.
• Carry out the process slowly. Avoid using excess force that may damage the base metal.
• Wear the necessary PPEs to avoid hazards.
• Use a properly ventilated environment when carrying out this process.
• When you are done, check for surface imperfections before taking the components to market. 

Conclusion

It is important to remove tack welds the right way to avoid destroying the surrounding material in the process. Some common removal techniques you can use are grinding, chipping, and machining. You can also utilize chemicals in some cases. Your choice depends on the size of the tack weld, the type of metal you are working with, and the desired surface quality. When removing tack welds, use the right technique, apply minimal force, and properly protect yourself from hazards.