How to Weld with a Torch

Most people think that you can only weld with a welding machine. The second you start learning more about welding, you realize that isn’t true. There are many ways to weld without a welder, including with a torch.

Torch welding uses a combination of gas and oxygen to create a combustible fuel, which you use to melt metal. It is a very effective form of welding that is very popular in certain industries and DIY communities. Plus, you can use the torch for other tasks, such as brazing and soldering.

Here is your guide to using a torch for welding.

Can You Weld with a Torch?

Before getting into the details, it’s important to firmly establish what you can and cannot do with a torch. If you have one in your DIY shed, you’re a very lucky welder. You absolutely can weld with a torch. Torches are also much more versatile than welding machines.

However, there are a few caveats. One is the type of torch you are working with. The best torches for welding are oxygen and acetylene gas-based torches. These torches can reach temperatures of over 5,000 degrees Fahrenheit, which is hot enough to melt most metals. 

Butane torches, propane torches, and regular utility torches you find in your average home improvement kit are usually not powerful enough to weld. However, you can use propane torches to weld softer materials with a lower melting point, such as brass. Propane and butane torches are also effective for other techniques, such as brazing

Another important thing to consider is the material you are working with. You can weld softer metals such as silver and aluminum with a torch. For metals with a higher melting point, such as steel, it is better to use electric welding. I prefer it anyway for working with steel since you are far more secure with your joint.

oxy acetylene torch in action

How to Weld with a Propane Torch

Propane torches are similar to acetylene gas torches because they use a combination of propane and oxygen to produce burning gas. These torches reach a higher temperature than butane torches. You can easily weld with them as long as you are working with the right materials. Make sure you are not using metals with very high melting points, such as steel.

Here are the steps to weld with a propane torch.

1. Prepare Your Propane Torch and Workspace

The first step in any welding process is preparing your equipment and workspace. Make sure your metals are clean and free of debris. Clean and declutter your workspace. You don’t want to accidentally set any other materials on fire! Clamp your pieces in position.

Then, prepare yourself. Put on safety equipment such as gloves and goggles. Make sure you are wearing sturdy shoes and long clothing to protect your skin.

Finally, prepare your torch. Check the fuel and oxygen levels. Attach the torch securely to the propane tank. Once you check that everything is working, you can move on to the next step.

2. Light The Torch

The next step is actually to light your propane torch. This is not as simple as lighting a match or turning on a switch. 

First, you have to open the tank’s fuel knob, which usually has a label that says “Open” or “On.” This allows the fuel to flow into the torch. Then, carefully bring your spark lighter to the spark cup. 

Adjust the flame size according to your needs. You can do this by opening and closing the knob. More oxygen will create a bigger flame, while less oxygen will create a smaller, less powerful flame.

The flame should be a controlled burn, tinged blue since blue is the hottest a flame can burn. That means your torch is hot enough for welding. 

3. Weld Along the Seam

Now, you’re finally ready to start welding! Start by melting the edge of one piece until it turns into a liquid. Then, push the pieces together. Go over the seam again with your torch flame to seal the bond. 

As you’re welding, make sure you maintain a consistent, steady speed. If you go too slowly, the metal will overheat, and you really want to concentrate the heat on just the edge of the metal. If you go too fast, the metal will not get a chance to melt properly.

You also need to keep your arm at a steady angle as you weld. I usually aim for an angle of about 45 degrees.

4. Finish the Weld

Once you’re done welding and you’ve melted all the metal along the seam with your propane blowtorch, it’s not time to relax. First, you need to take care of your equipment. Make sure your propane tank is safely turned off. Store it safely where you know nobody can use it to get hurt. Clean up the rest of your workspace.

Don’t move your project right away because the weld needs time to set. I like to leave mine overnight, so I know that it hardened properly before I start working with it anymore.

How to Weld with a Butane Torch

The answer to how to weld with a butane torch is…that you can’t. 

The reason why is that butane torches are much less powerful than propane or acetylene gas torches. Since their flames are weaker, they cannot reach temperatures high enough to melt the metals you are working with. 

If you need to weld, it’s better to use other equipment, such as a stronger torch (I recommend propane torches for softer materials and acetylene torches if you’re really getting serious). It might also be time to invest in a welding machine.

If all you have is a butane torch, then you can use another method for joining two metals, such as brazing and soldering (more on those later). However, actual welding, where you directly melt the two pieces you are trying to join, is impossible with such a low-powered torch.

Types of Torch Welding

As we’ve established, torches are very versatile tools. So, torch welding includes a lot of different techniques. There are actually a few different types of torch welding, which I will explain now.

You can divide torch welding into different techniques, which are the following.

Cutting 

Usually, when people talk about torch welding, they actually mean metal cutting. Cutting is the most common welding process that uses a torch. Instead of using heat to melt metals and fuse them together, you actually use the torch to cut the metal.

Heating 

Heating is when instead of melting the metal, you use the torch to heat up the metal. Maybe you need to make it more pliable or prepare it for another process. Using a torch to heat metal is easy, but it burns more fuel than more efficient methods.

Welding

Finally, you have regular welding, which is when you use a torch to melt the edges of two metal pieces and join them together.

You can also divide torch welding into different types based on the type of torch you are using, for example: 

  • Propane torch welding, because you are using a propane torch
  • Acetylene torch welding, because this process uses acetylene gas and oxygen

What Metals Can You Weld with a Torch?

While torch welding is possible, it is less powerful than electrical welding with a welding machine. That means that you can’t use torch welding on all metals. The best metals for torch welding are the ones with a lower melting point. These metals are also softer and more ductile.

A list of metals you can work with using torch welding includes:

You can weld harder metals such as iron and steel using powerful acetylene gas torches, but I find it much easier to use electrical welding at that point.

How to Braze with a Torch

If the only equipment you have at your disposal is a blowtorch, and you’re worried that it is not powerful enough to weld traditionally, don’t worry. There are plenty of other methods for welding metals together, including brazing.

Brazing is a technique that uses a filler metal alloy to combine two metals. You melt the alloy, which has a low melting point, instead of the metal itself. That means you don’t need as much power as you do in welding, and you can use even a butane torch. Then, the melted alloy glues the solid metal pieces together.

Brazing with a torch is easy enough to master once you follow these steps:

  1. Prepare Your Materials. Clean and deoxidize the metals you are working with. Get your filler material ready. Make sure you are wearing safety equipment. Check the fuel levels on your torch.
  2. Add flux. Treating the metal you are using with flux is an important part of brazing. You want to prevent oxidation, which is more likely to happen when brazing than with traditional welding. 
  3. Turn on your torch. Open the gas tank and use a spark lighter to light the torch. Adjust the flame size. The flame should burn blue, showing that it is hot enough to work with metal. Wait a few minutes until it gets hot enough.
  4. Heat the metal. For brazing to work, you need to heat all components equally. Bring the metal up to temperature.
  5. Add the filler metal. Then, pour the metal alloy you are using as a filler into the seam. Make sure you are using the right alloy for the materials you are working with.
  6. Melt the filler metal. Finally, it is time to melt the filler metal, although the residual heat will do part of the job. Work your torch over the metal in small circles until you see a melting pool, then repeat across the seam.
  7. Turn your torch off, put it away, and let the metal rest.

How to Solder with a Torch

Soldering is another alternative to traditional welding if you only have a torch at your disposal. It is very similar to brazing because you combine two pieces by melting a filler metal between them. However, soldering only uses one very specific alloy called solder. 

Soldering is great for working with delicate materials such as gold or small pieces, for example, in electrical circuiting. Here is how to solder with a torch:

  1. Prep your torch. Butane is the best for delicate work because its low flame won’t damage sensitive materials. Add enough fuel to your butane torch. Get your materials ready, including the solder. Clamp everything in place.
  2. Light the torch. Turn on the gas and use a lighter to ignite the flame. Adjust the oxygen and gas levels to adjust the strength of the flame.
  3. Heat the wire. You’ll know when it’s hot enough once the wire starts to change color.
  4. Add the solder and let it set.

Equipment Required

Here is the basic equipment you will need to torch weld.

  • A torch
  • Fuel (butane, propane, or acetylene gas)
  • Oxygen tanks (depending on your torch)
  • Cutting and welding attachments
  • A spark lighter to ignite the flame
  • Cleaning supplies such as solvents and wire brushes to clean the metal
  • Clamps and other equipment to keep the metal in place
  • Protective gear such as gloves and goggles

Tips and Tricks

If you want to master torch welding, here are some tips and tricks to help you out.

Always check the melting points of the materials you are working with to see if you can torch weld at all.

Make sure you protect yourself. Although torch welding does not produce a flame that is as bright as arc welding, it can still hurt your eyes.

Move in short runs whenever possible. Trying to get through a long line with a torch is harder than with a welding machine, as the fuel-oxygen levels fluctuate.

Final Thoughts

Torch welding is a widely accepted technique. Acetylene torches are the most powerful, but you can also weld softer metals with propane. You can also use torches for other applications, such as brazing and soldering.