Welding is an essential process in industries ranging from construction to automotive repair. However, before striking an arc, selecting the right metal is crucial for ensuring strong, durable welds. Whether you're a seasoned welder or just starting, understanding the key factors when purchasing metal for welding can save you time, money, and frustration.
Know Your Metal Type
Not all metals are created equal, and different welding processes require specific materials. The most commonly welded metals include:
- Mild Steel - Affordable, easy to weld, and commonly used for general fabrication. Works well with MIG, TIG, and stick welding.
- Stainless Steel - Corrosion-resistant and durable but requires special care due to its heat sensitivity. Best welded with TIG or MIG processes using the right shielding gas.
- Aluminum - Lightweight and strong, but it requires precise heat control and proper filler materials to prevent warping and cracking. TIG welding is often preferred for aluminum.
- Cast Iron - Brittle and tricky to weld due to its high carbon content. Typically requires preheating and slow cooling to prevent cracking.
Before purchasing metal, ensure that it matches your project requirements and welding method.
Understand Metal Thickness
The thickness of the metal affects the welding process and equipment needed. Thicker materials require higher amperage and a more powerful welder, while thinner metals demand lower heat settings to prevent burn-through.
- Sheet Metal (Thin Gauge) - Requires precise heat control. MIG welding with a lower voltage or TIG welding is ideal.
- Medium-Gauge Steel - Common in automotive and structural applications. Can be welded with MIG, TIG, or stick welding.
- Thick Metal (1/4" and above) - Requires higher amperage and may need preheating. Stick and flux-core welding are commonly used for thick materials.
Choosing the right thickness will ensure proper penetration and fusion without excessive distortion.
Check for Coatings and Contaminants
Some metals come with coatings, oils, or rust that can negatively impact weld quality. Before welding, consider the following:
- Galvanized Steel - Contains a zinc coating that produces toxic fumes when welded. Always remove the coating near the weld area and use proper ventilation.
- Painted or Oiled Metals - Must be cleaned thoroughly before welding to prevent weak welds and excessive smoke.
- Rust and Corrosion - While some rust can be welded through, heavy corrosion should be removed with a wire brush or grinder before welding.
Proper surface preparation ensures cleaner, stronger welds and minimizes health risks.
Match Your Filler Metal and Shielding Gas
Different metals require specific filler materials and shielding gases to achieve strong welds:
- Mild Steel - Typically welded with ER70S-6 wire (MIG) or E7018 electrodes (stick). Uses CO2 or a CO2/argon gas mix.
- Stainless Steel - ER308L wire or rods and argon-based shielding gas.
- Aluminum - Needs ER4043 or ER5356 wire/rod with 100% argon shielding gas.
- Cast Iron - Uses nickel-based electrodes and may need preheating and slow cooling.
Choosing the correct filler metal and shielding gas ensures better weld quality and prevents defects.
Consider Metal Storage and Handling
Once you've purchased the right metal, proper storage and handling are essential to maintain its weldability. Store metals in a dry area to prevent rust and contamination. If your metal has been exposed to moisture, clean and dry it before welding to avoid porosity in the welds.
Selecting the right metal for welding is a crucial step that impacts the strength and durability of your welds. By understanding metal types, thickness, coatings, filler metals, and storage, you can ensure a successful welding project with minimal issues.
For expert advice on choosing the best metals, welding supplies, and equipment, reach out to Baker's Gas and Welding! Give us a call at 877-930-5690 or email support@bakersgas.com for all your welding needs!
