Spot weld removal with the Powermax45 XP plasma system

In automotive body repair and other metal working applications, two pieces of metal that are spot welded sometimes need to be separated without damaging the base metal layer. The Powermax45^® XP plasma system with a handheld torch offers a fast, cost-effective solution to this problem.

Spot welding

spot welding is used extensively in the automotive industry. Spot welding uses electric currents to fuse metal pieces together. Manufacturers put two pieces of sheet metal together and use fitted electrode welding guns to apply current and pressure to the metal pieces. The pieces of metal generate heat by acting as a resistance to the electric current flow, liquifying and fusing the metal without the use of any filler material.

Spot welding is efficient, cost effective, and can be automated.

Traditional options for spot weld removal

Removing spot welds quickly and cost effectively without damaging the base metal layer can be challenging. Spot welds are frequently removed by drilling, cutting, or grinding the welds.

• Drilling – Operators use a drill to cut through the spot weld itself. The operator needs to be very careful not to drill through both layers of metal. Drilling spot welds takes about three minutes per weld.

• Cutting – Operators use a spot weld cutting tool to cut a circle around the spot weld. The operator needs to be careful not to cut or damage the lower layer of metal. Cutting spot welds takes about three minutes per weld.

• Grinding – Operators grind through the spot weld being careful to only remove the top layer of metal. When done correctly, this technique does less damage to the bottom layer of metal and takes less time than cutting or drilling, averaging two minutes per weld.

Spot weld removal with the Powermax45 XP

Using plasma gouging to remove spot welds involves gouging around the spot weld, making sure to go through only the top layer of metal. Operating at 10-amp output current and using the precision gouging nozzle and shield, an operator can use the Powermax45 XP to quickly gouge away the metal around the spot welds, allowing the pieces to be separated. The plasma arc can then be used to clean up – or wash away – the small amount of weld that is left on the base metal surface. (See video)

Precision plasma gouging using the Powermax45 XP offers several compelling benefits over traditional spot weld removal methods such as drilling or grinding:

• It’s considerably faster. Each spot weld can be gouged in seconds, not minutes.

• The operating cost is typically much lower. The process is faster, enabling increased efficiency.

• The process is less fatiguing on operators’ wrists, arms, and shoulders. The faster, less physically demanding process increases operator comfort and safety, particularly when removing a lot of spot welds.

The Powermax45 XP

The Powermax45 XP plasma cutter provides a recommended cut capacity up to 16 mm (5/8 inch), with fast cut speeds and automatic gas adjustment for quick, simple setup and operation. Duramax^® Lock torches support handheld and mechanized cutting of a wider range of metal thicknesses. The Powermax45 XP has an extensive array of application capabilities via specialty consumables, including fine feature cutting, extended reach cutting, gouging, precision gouging, flush cutting, and marking.

The Powermax45 XP is easy to use. Smart Sense™ technology ensures the air pressure is always correctly set and patented drag-cutting technology lets operators drag their torch right on the metal when cutting. Drag cutting is easier than holding a standoff and usually produces more accurate cuts.

Operators gain efficiency with the Powermax45 XP. Superior cut and gouge quality reduces time required for secondary operations like grinding and edge preparation. The torch disable switch enables faster, easier changeout of consumables, decreasing downtime and increasing overall productivity.

Perfecting spot weld removal with plasma

Perfecting using plasma for spot weld removal requires some practice. The trick is to hold the torch at a flat angle to create a shallow gouge and never let the top layer of metal get hot enough to impact the bottom layer. Operators can avoid damaging the bottom layer by releasing the trigger or flicking the torch up as soon as the metal of the top layer starts to melt.

1. To begin, set the amperage to 10 amp.

2. Place the plasma torch at a flat angle just beyond the spot weld.

3. Press the trigger and start the arc. As soon as the metal begins to melt, flick the torch up or release the trigger, allowing the metal to cool slightly.

4. Bring the torch back down or press the trigger to begin melting the top layer again. As soon as the bottom layer is revealed, flick the torch up or release the trigger.

5. Remove the metal around one half of the spot weld, then repeat the process on the other half.

Once the welds are gouged, the top layer should come off. If needed, insert a chisel between the layers to help separate them. The plasma cutter can be used to clean up any small amount of weld that is left on the base metal surface. 

Note: where the sparks from plasma gouging might be of concern, non-working areas should be protected with a screen or fire-retardant blanket.

Practice makes perfect

With practice, a skilled operator will quickly learn how to avoid gouging into the base metal layer or applying excess heat that could warp the workpiece. Once the technique is mastered, removing spot welds with the Powermax45 XP will be faster, easier, and more cost effective than alternative methods – saving time and improving working conditions for operators.

To learn how to maximize gouging performance with the Powermax45 XP plasma cutting system, contact a Hypertherm product expert.