The Beginner's Guide to Welding Sheet Metal

It's perfectly understandable to feel a bit apprehensive about welding, especially if you’re new to it. After all, you’ll be handling high temperatures, powerful machinery, and permanent alterations to sheet metal—there’s no easy fix if something goes awry. But don’t worry, with the right approach, protective gear, and tools, you can achieve strong, clean welds while minimizing risks.

The good news? Our team at Clickmetal has years of experience working with various types of sheet metal. We’ve learned exactly what it takes to ensure safe and successful welding. Keep reading for our comprehensive beginner’s guide to welding sheet metal, covering everything from essential equipment to step-by-step processes.

What Equipment Do You Need?

Unlike simpler methods like screwing, welding requires multiple specialized tools. Here’s what you’ll need to begin:

The Right Welding Machine

When it comes to sheet metal welding, two main types of welders are commonly used: MIG (Metal Inert Gas) and TIG (Tungsten Inert Gas) welders.

MIG welders are widely preferred for sheet metal welding because of their ease of use and versatility. They use a continuously fed consumable wire electrode and an inert gas shield to protect the weld from contamination.

If you choose a MIG welder, you’ll also need a gas cylinder filled with a shielding gas, usually a blend of argon and carbon dioxide. This gas shields the weld from atmospheric contamination, ensuring clean and robust welds.

TIG welders, on the other hand, utilize a non-consumable tungsten electrode and an inert gas shield. While they provide more precision, they demand greater skill to operate. Therefore, we’d recommend starting with a MIG welder for your initial attempts.

Wire Selection

The type of wire you’ll need depends on the metal you’re welding and the thickness of the sheet metal. Always match the wire diameter to the sheet metal thickness to avoid delivering too much heat, which could lead to warping or melting.

For MIG welding common metals, here are the standard wires:

• Aluminum: Use ER4043 or ER5356 aluminum filler wire.
• Mild Steel: Solid steel electrodes matching the composition of the mild steel being welded, such as ER70S-6 or ER70S-3.
• Stainless Steel: Solid stainless steel electrodes corresponding to the type of stainless steel being welded, like ER308L for 304/304L stainless steel and ER316L for 316/316L stainless steel.

Essential Consumables

• Shielding Gas: As previously mentioned, a mix of argon and carbon dioxide is often used for MIG welding. Avoid using 100% CO2 since it encourages deep penetration and can cause burn-through. Opt for a 75% argon / 25% carbon dioxide mix for better control.
• Contact Tips: These small components link the welding wire to the welding gun and must be compatible with the wire diameter you’re using.
• Nozzle and Diffuser: These parts help manage and direct the gas flow properly during MIG welding.

Additional Tools

Depending on your project, you might also need extra tools such as clamps, cleaning tools (like a wire brush or grinding wheel), and a welding table. For more detailed guidance, refer to the manufacturer’s recommendations for the specific metal and welding process you’re using.

How to Stay Safe

Welding sheet metal presents certain dangers, but there are many ways to protect yourself. Here’s where you should focus:

Wear Proper Safety Gear

• Welding Helmet: This is your primary defense. Pick a helmet with the appropriate shade rating for your specific welding process. Most helmets have a shade guide printed on them, or you can consult a welding supply store for recommendations based on your welding technique and materials. Ensure the helmet offers good visibility and a comfortable fit for extended work periods.
• Respirator: When ventilation isn’t sufficient, wear a respirator with the proper cartridges or filters for the metals you’re welding.
• Welding Gloves and Protective Clothing: Wear heavy-duty welding gloves, a welding jacket, and flame-resistant clothing to safeguard against sparks, heat, and molten metal.

Practice Safe Techniques

• Welding produces fumes that can be toxic. Always weld outdoors whenever possible to allow fumes to disperse. If indoor welding is unavoidable, use a Local Exhaust Ventilation (LEV) system to capture fumes and contaminants at the source before they spread throughout the workspace.
• Have a fire extinguisher easily accessible in your welding area in case of sparks or flammable materials nearby.
• Regularly inspect your welding helmet, respirator, and gloves for signs of wear and tear. Damaged equipment can compromise your safety; replace any faulty components immediately.

Missing out on any of these precautions can result in serious injury, so always prioritize safety. If you’re unsure or lacking confidence, consider practicing under the supervision of an experienced welder or seeking their advice first.

How to Weld Sheet Metal

Once you’ve gathered your equipment and ensured you’ve followed all the safety practices outlined above, you’re ready to begin your first weld! This guide focuses on MIG welding, as it’s the most beginner-friendly method. Mastering this technique will make learning other methods much easier later on.

Before moving on to your actual project, you may want to practice on scrap pieces to get comfortable with the settings and technique. This will allow you to experiment and find the optimal settings for your material thickness.

Ready to make some sparks fly? Follow these steps to create your first bead!

Step 1: Prepare the Metal

First things first, you need to prepare the sheets themselves.

Contaminants can interfere with a good weld, so thoroughly clean the weld area with a wire brush or grinder to remove dirt, grease, paint, or rust.

Next, decide on your joint type (butt joint, lap joint, etc.) and shape the metal edges accordingly. Beveling the edges can be beneficial for thicker materials (around 1/8” and above) to enhance penetration.

Step 2: Set Up the Welding Machine

Now, let’s get your welder set up! The exact steps may vary depending on your machine, so be sure to consult your welder’s manual for specifics. Here’s a general guide to get you started:

• Install the correct size MIG wire according to your machine’s recommendations and the thickness of the sheet metal you’re welding.
• Set the gas flow rate according to your manual (typically 20-25 cubic feet per hour). The gas flow rate helps shield the weld pool from contamination and ensures a clean weld.
• Begin with low voltage and wire feed speed settings. A good starting point is referencing a welding chart for recommended settings based on your material thickness, then fine-tuning as needed.

Step 3: Position the Sheet Metal

Position the pieces to be welded and secure them with clamps or tack welds if necessary. Clamps keep the pieces aligned during welding, while tack welds create temporary connection points for lap joints or to prevent warping on longer seams.

Step 4: Load the MIG Gun

Load the MIG gun with your chosen wire and ensure it feeds smoothly into the device. Any stuttering or erratic wire feeding can cause inconsistencies in the weld.

Step 5: Begin the Weld

Turn on the power switch on the welding machine and hold the gun to the metal. Then:

• Maintain a very short arc length (around 1/16”) between the contact tip and the metal. A long arc length increases heat input and can melt through thin sheet metal.
• Use a “stitch welding” technique. Make short, quick welds (about 1/2” long) with a slight pause (1-2 seconds) in between each weld to allow the metal to cool down. This prevents overheating and minimizes the risk of burn-through.
• Keep the travel angle between the torch and the metal at 10-15 degrees, pushing the torch slightly ahead of the weld pool. This angle focuses the heat on the leading edge, allowing for better penetration and creating a good bead profile.
• Focus on creating a consistent bead profile without excessive heat. A good weld bead should be slightly crowned (raised in the center) and have a smooth, regular appearance.
• Allow the welded area to cool down completely between weld passes. This prevents overheating and potential cracking in the weld.

Step 6: Finish Up

After finishing the welding, inspect the joint for quality. Look for cracks, porosity (air pockets trapped in the weld), or incomplete fusion. You can chip away any slag (the glassy byproduct of the welding process) with a chipping hammer and clean the area with a wire brush. You can also grind the weld seam for a smoother finish, but be cautious not to overheat the thin metal. Excessive grinding can create notches or gouges that can weaken the joint.

Don’t be discouraged if you don’t get it perfect the first time—welding is a specialized skill that takes years to master. Just keep practicing, and you’ll notice improvement with every arc you strike.

Elevate Your Welding Skills With Precision-Cut Sheet Metal From Clickmetal

Ready to dive into your next welding project? Get the exact sheets you need with Clickmetal! We offer a wide variety of high-quality sheet metal in different thicknesses, all cut to your precise specifications. Choose from:

• Aluminum (grades 1050H14, 5251H22, 6082T6, and 5083’0’)
• Stainless steel (grade 304)
• Galvanized steel (grade DX51DZ+275MAC)
• Mild steel (grade CR4)

All our sheet metal is manufactured in-house with top-of-the-line equipment, so you can be confident you’re receiving top-notch quality with every order. We process most orders within 3-5 working days, followed by next-day delivery through a reliable courier service, so you can get started as soon as possible.

Don’t waste time searching for the right sheet metal. Browse our extensive selection online and find the perfect fit for your project today!