Forge Welding 101: What Is It All About and How Does It Work?

Do you want to experience the pure thrill of joining metal as our ancestors did for thousands of years? I’m talking about forge welding, of course.

You’ve probably seen it in the movies. You know the scene: a giant blacksmith hammers away at the red molten metal, joining a sword blade to its shaft.

Of course, they simplify things in the movies.

For instance, in the movies, they hammer away at the glowing metal. But when you’re actually welding, you want to make sure you hammer with soft, even strokes.

So why should you learn forge welding? Aside from fulfilling an anachronistic desire, forge welding is an incredibly useful way to join loose steel together. Plus, it is simple, quick, and doesn’t require specialized tools or equipment.

You don’t even need to look like a medieval blacksmith to do it.

Today there are many forge welding setups in clean, modern workhouses across the world. In fact, forge technology and robotic hammers only continue to advance! Still, there’s something undeniably cool about those medieval blacksmiths, isn’t there?

The History of Forge Welding

man wearing yellow hard hat

Image by Karl Allen Lugmayer from Pixabay 

The year is 4000 BC and you’re busy forging together two pieces of a bronze spear. Or, maybe you’re constructing a steel farming tool.

Either way, you’re forge welding. In fact, you’re one of the founding pioneers of the welding process!

But that’s only the beginning.

For the next 5,900 years, humankind forged tools out of bronze, steel, and other metals. All of this forge welding was performed by hand.

19th Century

But then along comes the 1800s and the modern industrial era. With the introduction of steam, electric, and hydraulic technologies, industries of all kinds emerged. Most importantly of which, at least for the world of welding, was the Bessemer steel-making process.

Suddenly forgers had access to cheap steel and the high-powered machines needed to forge it all together. But by the end of the 19th Century, these steam-powered hammers gave way to smaller, electric-powered hammers.

20th Century

World War II brought forth another huge shift. The end of the war also marked the end of the industrial era and the beginning of today’s information era.

When it comes to forge welding (and forging in general), the world saw a massive technological leap with the introduction of induction heating and solid state electrical induction heaters.

Induction heating uses electrodes to send electric currents throughout the metal, superheating it until it can be manipulated and welded.

This method is both fast and cheap. But it lacks a certain finesse, and welding through induction heating can be messy. That’s not to mention it can also be inaccurate.

Which is why in the later part of the 20th Century many people returned to forge welding. This change was not only thanks to a renewed interest in more traditional forging arts but also because forge welding is a fantastic way to get accurate welds for mass production.

Forge Welding Basics

welding aluminum

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By now, you’re probably wondering, “How can I start forge welding?”

Don’t worry, because we’ve got you covered. The great thing about forge welding is that you don’t need special licensing from the government to do it. However, if you want to work in an industrial shop as a forge welder, you’ll need formal training and certification from a school.

That said, if you’re working on your own projects you’ll need some basic starter equipment.

What you need

Obviously, you’ll need a forge. Your forge should consist of a firepot, a work surface, and a blower.

Keep in mind, forges come in all shapes and sizes. Some are brick, while others are iron. Some people even improvise with brake drums! The type of forge you choose is entirely up to you.

Next, you’ll need an anvil. A used anvil can cost less than $2 per pound, so look around before buying one.

Then, you’ll want some blacksmith hammers. A pein hammer, like the Picard Swedish Blacksmith’s hammer, will work fine for starting out. You’ll also need a good set of blacksmith tongs with which to reach into the forge.

Also, you’ll need some flux, which is the material that will bond the metal together.

Finally, you’ll need a vise. Stay away from machinist vises. These will fall apart under the hammer blows. Instead, get a blacksmith vise.


Before you do anything else, you’ll need to prepare your forge, anvil, and steel. Start by preheating the forge to 2,300 degrees Fahrenheit.

While your forge is heating up, you can prepare the anvil. You want a hot anvil, which will prevent heat from getting sucked away from your weld. To preheat the anvil, heat a large piece of steel in your forge and lay it across the top of the anvil.

Finally, you can prepare the steel for the weld. You’ll want a finely feathered scarf.

To do this, heat both pieces of steel until they are glowing orange. Then, hammer evenly (not too hard) to flatten the ends of the two metal pieces and prepare them for joining


Are you ready to get to the good stuff?

Now you can start the actual welding process. Once your scarf is prepared, place it into the forge. Be sure not to place it directly on the coals or heating surface. Instead, hold it above the heat source.

When the material is glowing a nice orange, sprinkle it with flux. Borax flux is the best. This creates a sort of insulation to keep the heat inside the steel.

Place the steel back in the forge and heat it to a yellow color. Now comes the tricky part.

You’ll need to remove the steel pieces, placing the scarfs together. You only have about two seconds before they begin cooling rapidly, so be sure you have everything ready before you remove them from the forge.

If they don’t stick, you need to start again. If they do, great!

Now, softly hammer them together until they’re joined completely. You’ve finished your first weld!

A word of caution

Before you start any welding, remember that flux is a powdery substance. After you apply it to the weld and place it in the forge, it will melt into an extremely hot, glass-like surface. But some pieces might remain loose.

When you pull your weld out of the forge, keep an eye out for clouds of hot flux dust.

No matter your level of welding experience, it’s always best to wear protective clothing. And above all, keep pets and children far away from you when you’re forging!

Helpful Tips and Advice

welder wearing blue uniform

Image by wyllyston ofman from Pixabay 

Forge welding can be a fun hobby or a useful skill. However, small mistakes here and there can turn a simple weld into a disaster. When you’re dealing with high heat and high pressure, you want to make sure you do everything right the first time.

Fortunately, following some practical forge welding tips can help ensure a great weld every time.

Welding tips

For starters, use coal in your forge. It’s better than gas and can reach a higher temperature than wood.

Also, make sure your forge is well-packed with zero air pockets.

Keep at least four inches of space between the coal and your metal of choice. Touching the heat source can introduce debris to your weld and jeopardize its final integrity.

Plus, take the time to wire brush your steel or iron before welding. That will help remove any impurities.

Heating tips

Do you wonder how you’ll know when your metal is ready for the weld? There’s no exact science, but you can use colors as a great guide.

For instance, when your metal reaches the same yellow color as the fire, it’s ready. However, if you see sparks it’s too hot.

That being said, if you see spots on your iron, like salt and pepper, then your metal isn’t hot enough.

Also, remember that both pieces of your weld need to be the same color.

Finally, high-carbon steel requires lower temperatures than mild steel or iron.

Now, you’re ready to get out there and weld!

Try Your Hand at Forge Welding

welding technique

Image by idobicollection from Pixabay 

Are you ready to try your hand at forge welding? Once you’ve assembled all the tools, you’re all set to go.

Remember that your first few welds are probably going to stink. Forge welding is more of an art than a science, and it takes both patience and practice.

You’ll want to begin with cheap iron or steel bars that you can reuse. You won’t make high-quality tools with this metal, but you’ll be able to practice over and over again without worry.

Once you’ve perfected this fine art, you’re ready to get productive. For example, you can make your own pein hammers. And when your friends complain that tools are too expensive, you could even have a nice side gig!

Do you have any forge welding tips? Leave us a comment below.

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