Corner welds might seem intimidating at first, but for anyone starting out with a Jasic welder, they’re a fundamental skill that unlocks a world of fabrication possibilities. Whether you’re joining two pieces at a 90-degree angle for a box, a frame, or a workbench, mastering the corner weld is crucial.
This guide will walk you through the practical steps to achieve strong, clean corner welds with your Jasic machine, focusing on both outside corner and inside corner (fillet) joints.
Understanding the Challenge of Corner Welds
Corner welds present unique challenges:
- Heat Concentration: Corners act as “heat sinks,” meaning heat can build up quickly, leading to burn-through, especially on thinner materials.
- Fit-Up: Gaps or misalignment can make strong welds difficult.
- Positioning: Holding the torch correctly and maintaining a consistent travel speed is key.
- Visibility: Especially on inside corners, seeing the weld pool can be tricky.
But don’t worry! With a Jasic machine’s reliable arc and the right technique, you’ll overcome these challenges.
Before You Strike an Arc: Essential Prep
Preparation is 80% of a good weld. Don’t skip these steps!
- Safety First! Always wear your auto-darkening welding helmet, flame-resistant gloves, jacket, and closed-toe shoes. Ensure good ventilation.
- Material Selection: Start with mild steel in a manageable thickness (e.g., 1.5mm to 3mm / 16 to 11 gauge). This thickness is forgiving for beginners.
- Cleanliness is King: Grind away any rust, paint, oil, or mill scale from the edges and about an inch back from the joint area. Contaminants cause porosity and weak welds.
- Fit-Up is Crucial:
- Outside Corner: Ensure the two edges meet as tightly as possible with no gap.
- Inside Corner (Fillet): The two pieces should meet at a perfect 90-degree angle, forming a clean corner. Use clamps, magnets, or a welding jig to hold them firmly in place.
- Set Up Your Jasic:
- Process: For beginners, MIG welding (GMAW) is highly recommended due to its ease of use and consistent results. Ensure your Jasic machine is set to MIG.
- Polarity: For solid wire and shielding gas, your Jasic should be set to DC Electrode Positive (DCEP), meaning the welding gun is positive and the work clamp is negative.
- Shielding Gas: For mild steel, use a 75% Argon / 25% CO2 mix (C25) for MIG. Ensure your gas cylinder is open and the flow rate is set correctly (typically 10-15 liters per minute for shop use).
- Wire Type & Size: For mild steel, ER70S-6 wire is standard. Start with 0.8mm (0.030″) or 0.9mm (0.035″).
- Settings (Your Jasic’s Sweet Spot): Refer to your Jasic machine’s helpful chart (often found inside the wire spool cover) for starting voltage and wire feed speed (WFS) settings based on your material thickness and wire size. For 1.5-2mm steel, you might start around 16-18V and 4-6 m/min WFS. Always test settings on scrap material first!
The Weld: Techniques for Inside and Outside Corners
A. Outside Corner Weld (Lap/Edge Joint Variation)
This is often the easiest for beginners as you’re welding on a flat plane.
- Torch Angle: Hold the MIG gun straight into the joint, at a 90-degree angle to the workpiece, or with a slight push angle (5-10 degrees in the direction of travel).
- Stick-Out: Maintain a consistent wire stick-out (the length of wire extending from the contact tip) of about 10-15mm (3/8″ to 5/8″).
- Initiate Arc: Position the wire at the start of the joint and pull the trigger.
- Travel: Use a steady “push” technique. Move the torch smoothly along the joint.
- Weaving (Optional, for wider welds): For slightly wider welds, a small “C” motion or back-and-forth “Z” motion can be used, focusing on fusing both edges.
- Observation: Watch the weld puddle. It should be wetting into both pieces of metal. If it’s building up on one side, adjust your angle slightly.
B. Inside Corner Weld (Fillet Weld)
This is where the real skill comes in, as you’re filling a “V” shape.
- Tacking First! Always tack the pieces together at the start, end, and along the joint. Tacks prevent movement and maintain the angle.
- Torch Angle is Key: This is critical.
- Work Angle (Sideways): Aim for a 45-degree angle to each piece of metal. This ensures equal heat distribution.
- Travel Angle (Push/Pull): For MIG, a push angle (5-10 degrees) is generally preferred for better visibility and less spatter.
- Stick-Out: Maintain 10-15mm (3/8″ to 5/8″).
- Initiate Arc & Weld Pool Formation: Start at one end. Observe the weld puddle forming in the very corner. You want it to “wet out” and fuse with both the vertical and horizontal pieces.
- Travel Motion (Weaving Recommended):
- Small Circles/Figure 8s: For a consistent bead, use small, tight circles or figure-eight patterns. This helps fill the corner and ensures good fusion.
- “Whip and Pause”: For beginners, a simple “whip and pause” motion can be effective. Push forward a little, pause slightly to let the puddle fill, then whip forward again.
- Observation: Focus on the leading edge of the weld puddle. It should look like a “wetting” action, where the molten metal flows smoothly into both parent materials. If the puddle is too large and soupy, you’re too slow or too hot. If it’s too narrow and tall, you’re too fast or too cold.
Common Problems & Jasic Solutions
- Burn-Through (Especially outside corners):
- Jasic Solution: Lower your voltage or wire feed speed. Increase your travel speed.
- Lack of Fusion / Cold Lap (Weld sits on top, doesn’t penetrate):
- Jasic Solution: Increase your voltage or wire feed speed. Slow down your travel speed. Ensure your work clamp has a good connection.
- Excessive Spatter:
- Jasic Solution: Adjust your voltage/WFS for a smoother arc. Ensure proper stick-out. Check your gas flow. Some Jasic machines have inductance control which can reduce spatter.
- Inconsistent Bead:
- Jasic Solution: Focus on maintaining a consistent torch angle, stick-out, and travel speed. Practice, practice, practice!
Final Tips for Success
- Practice on Scrap: Never go straight to your project. Use scrap pieces to dial in your Jasic settings and refine your technique.
- Listen to the Arc: A good MIG arc sounds like sizzling bacon. A crackling or popping sound indicates problems (often too much voltage or too little WFS).
- Watch the Puddle: Train your eye to read the weld puddle. It’s your best indicator of what’s happening.
- Post-Weld Cleanup: Chip off any spatter (a good anti-spatter spray helps!), and grind the weld smooth if needed for aesthetics or further fabrication.
Your Jasic welder is a powerful tool designed for ease of use. By understanding the principles of heat control, torch angles, and consistent movement, you’ll be laying down strong, beautiful corner welds in no time. Happy welding!