Stick welding, also known as Shielded Metal Arc Welding (SMAW), is done by using an electric current to create an arc between a coated electrode (the stick) and the base metal, melting both together to form a weld.
Here's a breakdown of the process:
Understanding the Process
The stick welding process relies on a few key components working together:
- Power Source: A welding machine that supplies the electric current.
- Electrode Holder: This holds the welding electrode.
- Electrode (Welding Rod): A metal rod coated in flux. The core metal becomes the filler metal for the weld.
- Base Metal: The metal you are welding.
- Ground Clamp: Connects the welding machine to the base metal, completing the electrical circuit.
Steps for Stick Welding
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Preparation:
- Clean the Base Metal: Remove any rust, paint, or contaminants from the area to be welded using a wire brush or grinder. A clean surface ensures a strong and sound weld.
- Select the Correct Electrode: Choose the appropriate electrode type and size based on the type and thickness of the metal you're welding, and the welding position. Different electrodes are designed for different materials (e.g., steel, stainless steel, cast iron).
- Set Up the Welding Machine: Adjust the amperage (current) on the welding machine according to the electrode manufacturer's recommendations and the thickness of the metal.
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Strike an Arc:
- Scratch Start: Gently scratch the electrode against the base metal like striking a match. Lift the electrode slightly as soon as the arc is established to maintain the arc.
- Tap Start: Tap the electrode against the base metal and quickly lift it to create the arc.
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Maintain the Arc Length:
- Hold the electrode at a consistent distance from the base metal, typically equal to the diameter of the electrode's core wire. Too long of an arc results in a weak, spattery weld. Too short of an arc can cause the electrode to stick to the base metal.
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Travel Speed and Angle:
- Travel Speed: Move the electrode at a steady pace along the joint. Too slow results in excessive heat and penetration; too fast results in insufficient penetration and a weak weld.
- Work Angle: The angle of the electrode in relation to the direction of travel.
- Travel Angle: The angle of the electrode in relation to the weld joint. These angles are determined by the joint configuration, the position of welding, and other factors.
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Make the Weld: As the electrode melts, it deposits molten metal onto the base metal. The flux coating on the electrode melts as well, forming a slag that protects the molten weld pool from atmospheric contamination.
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Break the Arc: To stop welding, quickly pull the electrode away from the base metal.
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Clean the Weld: Once the weld has cooled, chip off the slag using a chipping hammer and wire brush. Inspect the weld for any defects, such as porosity or cracks.
Key Considerations
- Safety: Always wear appropriate personal protective equipment (PPE), including a welding helmet, gloves, and protective clothing.
- Practice: Stick welding requires practice to master. Start with simple welds and gradually increase the complexity.
- Troubleshooting: Be prepared to troubleshoot common problems, such as sticking electrodes, porosity, and undercut.
Advantages of Stick Welding
- Portability: Stick welding machines are relatively compact and portable.
- Versatility: Can be used to weld a wide variety of metals.
- Cost-effectiveness: Stick welding equipment is relatively inexpensive compared to other welding processes.
- Outdoor Use: Less susceptible to wind compared to some other welding processes because the flux shielding is not disrupted as easily as a gas shield would be.
Disadvantages of Stick Welding
- Slag: Requires chipping off slag after each weld.
- Lower Deposition Rate: Slower than some other welding processes.
- More Skill Required: Generally considered to require more skill than MIG welding.
- Electrode Changes: Requires frequent electrode changes.
