Welding seems to be effortless, primarily when you work on thicker material. However, welding metal sheets can be tricky. Small mistakes can result in wrong welding or creating holes in sheets. This brings a question: How to weld sheet metal? Knowing the answer is crucial to weld two metal sheet pieces.
Remember, welding sheet metal can be complicated if you don’t have the right tools. You could end up with weak welds. In worse scenarios, you could cause damage to the sheet metal. However, you don’t need to worry. This in-depth guide to welding sheet metal will give you everything you need to get going. So, let’s get started!
Overview of Metal Sheet Welding
Let’s start with the basics of the welding process.
Welding is the process of joining two metal sheet pieces together. This process uses an additional material called filler. The high beam melts the material and adds filler between the two pieces. Upon cooling, the melted filler creates a joint between the two pieces. This is the best way to create bonds between metal pieces.
We can use welding sheet metal for many different purposes. Sheet metal can be cut into various shapes and sizes and welded together to join. People often use it for car body panels and other structures. Metal sheet welding requires proper technique and tools for strong welding.
As I said, the welding process melts metal sheets. However, this melting can be difficult when the sheets are thin. Therefore, when welding thin sheet metal, it is essential to be mindful of the heat applied to the sheet. Too much heat can cause warping and blow-through.
Therefore, I recommend running a series of short welds in small sections when welding sheets. You should avoid trying to run a single bead across the entire thickness. This will reduce the heat that must be put into it and strengthen the joint. If you do so, the metal sheet might melt excessively, damaging the sheets.
Tools & Equipment Needed for Welding
Welding sheet metal is a highly technical process requiring many tools. You’ll need protective gear and some measurement tools to keep yourself safe. Here is a list of some other key tools and equipment.
- A metal file is an excellent tool for removing slag and burn marks from a weld.
- In addition, a wire brush can be helpful when cleaning up welds and other areas.
- Another essential tool is a sheet metal gauge, which helps you determine how thick the metal is.
- You should also use argon gas or an argon-CO₂ mix. This helps avoid contamination on the weld’s surface.
- You should arrange C-clamps or locking pliers to hold the welding materials. This enhances the ease of welding.
- A scribe is another tool for marking workpieces before cutting or welding them. A high-quality scribe with a tungsten tip will last longer.
How to Weld the Metal Sheets? Step-by-Step Process
Once you have the tools and equipment, you can start welding. I will discuss how you should weld in steps in the section below. I aim to go step by step so that you get a complete understanding of welding. So, let’s jump in!
Step 1: Clean the Metal
First, you should clean the metal sheets carefully. Generally, sheets have impurities and other contamination on their surface. These contaminants can affect the welding process and induce oxidation on the surface of the weld. Therefore, you should use a wire brush or sandpaper. I recommend using both of these cleaning tools for the best results.
Step 2: Clamp the Metal Sheets Tightly
Generally, welders neglect the importance of clamps. However, I recommend that you use these clamps. The reason is that they keep the metal sheets stable at one position. The sheets won’t slip away during welding, which is a significant benefit. Once sheets are clamped, you should double-check that they don’t move. You can use either C-clamps or locking pliers, depending on your preferences.
Step 3: Set Up the Welding Machine
Other MIG and TIG welding machines can weld metal sheets. You can use any of them, depending on your preferences. The TIG machines use filler rods to create the weld. On the other hand, the MIG generally uses a thin wire to make the weld.
Whichever machine you use, set the voltage to a low point. This ensures that the metal sheets don’t melt during welding. You can gradually increase the voltage if the sheet is of higher thickness. This will help avoid unexpected events or accidents. Generally, TIG welding machines create very smooth welds, and vice versa.
Step 4: Create Small Welds or Tacks with Short Brust
I don’t recommend thoroughly welding the metal sheets. Instead, you should do it in tacks, which means there should be welds at an inch’s distance from each other. This will ensure that metal sheets don’t melt excessively due to bulk welds at the same point.
Moreover, you should use pulse welding techniques when joining metal sheets. In this method, you apply heat for 1 to 2 seconds. This small (shorter) burst will ensure smooth welds on the surface. A long burst might melt the sheets more than necessary.
Step 5: Finish the Weld with Post Processes
The cooling process ensures the strength of the weld. After welding, you should give the weld enough time to cool and solidify. If you are in a hurry, you can apply water mist to the weld, speeding up the welding process.
The last step is post-processing, which includes grinding the welds to make them even and smooth. Different machines are used in post-processing. Some welders apply a thin layer of coats to increase the weld signs. Moreover, the painting of the weld also improves the visual appearance of the metal sheets.
Common Metal Sheet Welding Methods
Welding is a stand-alone technique that joins two metal pieces. However, there are different ways through which this process is done. Each welding technique is different and has its pros and cons. Let’s discuss the various welding processes:
1- MIG Welding Process For Sheet Metal
MIG, or gas metal arc welding, is an excellent method for welding sheet metal. It combines a continuous solid wire electrode with inert shielding gas to form a weld puddle. This welding process uses aluminum, stainless steel, and mild steel.
It produces high-quality, consistent welds and is popular for many projects. In MIG welding, the welder feeds a continuous solid wire into a weld puddle, which melts and forms a weld bead. Inert shielding gas surrounds the puddle to prevent atmospheric contamination.
Choosing a wire smaller than the metal is best when welding sheet metal. This reduces the energy it takes to melt and minimizes the appearance of burnout. The compatibility of filler with the properties of the material being welded is key. I highly recommend avoiding choosing incompatible fillers.
Quick Highlight: Choosing thinner filler is always inefficient and results in weaker welds. Therefore, I suggest you use filler with a higher thickness. This will create a more robust weld with excellent strength. It will melt and have more power to hold the two metal pieces. Thinner filler can melt quickly without making a weld of enough strength.
2- TIG Welding Process for Sheet Metal
The TIG Welding process is an effective way to weld sheet metal. What I like about this process is that it helps avoid the material’s distortion. It involves establishing an electric arc between a non-consumable electrode and a welded part. This technique requires a tungsten electrode and a shielding gas.
The shielding gas is generally a combination of argon and helium or pure argon gas. Typically, a tungsten electrode with the most minor diameter is preferred. Why? Because it avoids burning or melting the sheet during TIG welding sheet metal. The 0.020 and 0.040-inch thoriated tungsten anodes and the 1/16 inches of created tungsten are ideal for this process.
When welding sheet metal, make sure you use a high-quality TIG torch. It is necessary to ensure the safety of the welder and the arc. TIG welding is very versatile and compatible with various metals. It can easily weld sheet metal, including aluminum, steel, and stainless steel.
Many seem to be confused when choosing between MIG and TiG. You should consider the type of material you’ll work with when deciding between TIG vs. MIG welding. For example, MIG welding is better for thicker materials like sheet metal and steel. On the contrary, TIG welding is better suited for thin materials, such as aluminum or stainless steel.
3- Laser Welding Process for Sheet Metal
Laser welding is an effective way to weld sheet metal. As a result, many industries, including aviation and automobile manufacturing, use it. Its advantages over traditional welding processes include the following:
- High Speed
- Small Deformation
- Beautiful Weld Seam
The base metal is heated and vaporized during laser welding, creating a narrow tunnel called a keyhole. This tunnel allows the laser to penetrate deeply into the metal. Depending on the type of metal, the depth of the welds can vary from 2 mm to 25 mm. However, a few key factors determine how deep the welds are.
Welding Stainless Steel Sheets
Performing stainless steel welding can be challenging, mainly when working with thin-gauge metals. Stainless steel is much more sensitive to heat input and can warp or burn if exposed to too much energy.
So, choosing the correct welding process for stainless steel sheets is essential. Controlling the heat applied to sheet metal and the filler metal is crucial. Selecting a suitable gas for your welding machine when welding sheet metal is also essential.
A tri-blend shielding gas with argon and helium is usually the best option for MIG welding stainless steel. We shouldn’t use a low-carbon dioxide blend too often to boost heat transfer to the workpiece. It can lead to oxidation.
Welding Aluminum Sheets
Welding sheet metal, especially aluminum, needs skill and the right tools for good results. Choosing the right shielding gas is vital. So is the pre-weld and post-weld processing. Both steps must follow specific specifications. Welding Aluminum also poses other challenges due to its following properties:
- High thermal conductivity
- Rapid heat transfer
- Formation of an oxide layer during welding.
It is crucial to consider these factors before we start welding aluminum metal sheets. You should also use the proper methods to ensure strong and dependable welds. Using the right tools will lead to successful aluminum sheet metal welding projects.
Another challenge is porosity, which results from hydrogen in liquid aluminum. Once the aluminum and filler material solidifies, the hydrogen can no longer hold onto it. Instead, the filler absorbs the metal, producing porosity.
A welder should use more argon in the shielding gas when welding aluminum. This is because argon doesn’t react with aluminum, unlike oxygen. In addition, it helps prevent oxidation, which can damage the weld.
Conclusion
Welding sheet metal is not rocket science. However, it can be tricky to complete if you don’t know the process. Moreover, you must have the right equipment and materials. It includes sheet metal, welding rods, a welding machine, and a clamp.
Manufacturers use the welding machine to generate the heat needed for the weld. Once you have all the materials and tools, you can start welding. In this article, I have explained the welding process in simple steps. Moreover, you’ll also learn about the standard welding methods used for metal sheets.