Things You'll Need:
- 3 12- or 16-volt car batteries
- Welding wand (stinger)
- Protective eye shield
- 2 battery cables
- 1 ground cable (with clamp)
- Wire brush
- Welding rods
- Hammer
- Gloves
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Step 1
Arrange three 12- or 16-volt car batteries within reach of the broken parts that need to be repaired. Placed on a level surface, the batteries must be free from water and debris while welding. Clean the broken metal parts with a wire brush. Remove as much dirt and paint as possible from the areas to be welded. Use extra pieces of metal to create a bracket if two metal parts cannot be welded directly together because of damage. Clean the added material completely before you spot weld with a car battery.
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Step 2
Connect the ground cable to the no. 3 battery's positive post. Connect a shorter battery cable to the no. 3 battery's negative post and to battery no. 2's positive post. Connect a short battery cable to battery no. 2's negative post, and connect it to battery no. 1's positive post. Finish the battery circuit by connecting the welding wand to battery no. 1's negative post. The batteries are now joined in parallel. Rather than one big battery that produces 12 or 16 volts of power, the three batteries will be producing 36 or 48 volts of welding power. You can use a voltmeter to check how much power is being produced. Just use the meter leads to touch the ground cable and the welding wand "stinger" to get a voltage reading. Thirty-eight volts is plenty of power to spot weld with a car battery as the power supply.
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Step 3
Connect the ground cable to the frame of the vehicle being repaired. Use the ground clamp to grasp the frame of the vehicle near the repair. Make sure that you are connecting the ground wire so that when the welding wand and electrode are touched to the repair surface, the electric current can flow through the metal parts to the ground clamp. Without a closed circuit using both the welding wand and the ground clamp, welding cannot be accomplished. Clamp the ground as close to the repair as possible without obstructing the area that needs to be welded. Touching the ground clamp with the welding rod will only weld the ground clamp and not the area that needs repair.
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Step 4
Put on heavy gloves and eye protection. Brazing goggles can be worn if the protective glass has been exchanged for welding-grade protective shielding. Brazing goggles do not have a welding-grade protective glass to shield the eyes from damage. If a welding hood is not something you want to bring with you on your trip, use brazing goggles and welding glass during off-road spot welding with a car battery. Insert a welding rod into the stinger wand and tighten. Cover your eyes with the protective welding glass and goggles and touch the electrode in the stinger to the repair. If the electrode produces enough power to begin to weld, it will produce a bright electric spark and stick to the metal it has melted. Now the repair can begin.
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Step 5
Weld a bracket over the broken framing or join metal parts directly on the off-road vehicle. Hold the piece in position and tap the welding rod to the edges of the metal where they meet. You must hold the welding rod steady in place long enough for the two metals to be melted and the electrode to cause the joining of the repair metals and the elements of the welding rod. Once a weld has started, move the electrode down the length of the seam steadily and with enough control and speed to melt the seam together evenly. Using a car battery to spot weld does not produce the best results. Remember to repair the broken parts enough to get the vehicle home for a professional fix later.
