How Do You Weld Cast Iron

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So you have that piece of cast iron you’ve been thinking about welding but are just now finding time to get around to it. But can you even do this from home? Do you have the right tools to do it right? How do you weld cast iron? 

Welding cast iron isn’t impossible, but it’s also not the easiest task to perform, which is why we wrote this article to help you out.  

If you’ve ever wanted to learn how to weld cast iron from home, you’re in luck. In this tutorial, you’ll learn all that there is to welding cast iron. 

We’ll discuss everything from what you need to prepare for this project to what type of cast iron works best and lots more. Plus, you’ll learn how to safely perform this project, including using the correct protective gear and handling cast iron safely and without suffering from burns.

Ready to start? Let’s do this!

Prepping for a Cast Iron Weld Project

1. Identify the Alloy

Grey Cast Iron

Grey cast iron is a grey-colored iron. It is grey in color due to the graphite particles found in its fractures. This is typically caused by the main alloying elements being too weak to completely remove all the carbon. The result is a grey cast iron that usually has a dull grey appearance to it.

White Cast Iron

We are all familiar with cast iron that melts at a comparatively low temperature. However, there are some things that you may not know about cast iron. Some of them may be surprising. 

For example, the famous White cast iron, which we all use on the stove, is a type of cast iron that is made of a specific mixture of pig iron and carbon.

White cast iron is a type of wrought iron that contains 10 to 30 percent chromium and 5 to 10 percent nickel. It can be easily formed into shapes, and it has properties that make it useful for a range of industrial applications. 

Cast iron is a traditional metal that was used in the past to make cast items, such as pipes, pots, and pans.

Ductile, Nodular, or Malleable Iron

The terms Ductile, nodular, or malleable refers to a type of cast iron that can be easily shaped and formed. Its alloys are sometimes used to make castings, however, most of the time are used to make castings. 

It’s hard to imagine, but it’s true. Malleable cast iron is easily formed by heating and molding. This means that it is a great way to cut to a specific size, hold an exact shape, and can even be stamped out into a sheet metal.

2. Clean the Casting Thoroughly

This is a very important step before welding. Your casting needs to be super clean and not just wiped down with a rag. A grinder will be best for the difficult-to-remove materials. A good solvent will help immensely with cleaning. 

3. Select a Preheat Temperature

If you’ve ever had to weld cast iron, you know that it’s a tough job. The heat picked up by the iron is intense, and you have to work quickly or you can seriously damage the metal. If the job at hand is welding cast iron, you need to select a preheat temperature that will ensure that the metal is hot enough to minimize the risk of damage.

Also Read: How Do You Weld Brass?

Selecting a preheat temperature for your cast iron vessel is an important step to ensure that your weld puddle remains tacky. There are several factors to consider when selecting a preheat temperature, including the thickness of your weld, your skill level, the weld type, the amount of material (steel, cast iron, etc.), your desired heat treatment, and the area of the weld.

Select an Appropriate Welding Technique

1. Manual Metal Arc Welding (MMA)

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Metal Arc Welding (MAW) is a great method of joining metals together, but it requires a special type of torch and a lot of skill to perform without damaging the workpiece in the process. MAW is a type of equipment welding that uses an electric arc instead of the flame of a traditional oxy-acetylene welding torch.

2. MAG Welding

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MAG welding is the process by which cast iron is welded with a MIG (Metal Inert Gas) welding gun. The process is a semi-automatic process that requires you to hold the torch in the proper position for a short period of time, which is usually only a couple of seconds, to weld the cast iron. The weld can be deep or shallow, depending on the size of the piece you are working with.

3. TIG Welding

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TIG Welding is a welding process that uses two welding electrodes to weld the metals at the same time. This method is ideal for joining dissimilar materials like metals and plastics. The TIG welding process can also be used for repairing and assembling. The method is standard in the automotive industry.

4. Oxy Acetylene Welding

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Oxy-acetylene welding (also known as oxy-fuel welding or flame cutting) is a welding technique that uses a small amount of oxygen to combine or “burn” two pieces of metal in a controlled way. The process is also known as oxy or gas welding because the oxygen is delivered in a gas form. Most oxy-acetylene welders are gas generators that supply the oxygen to the weld.

5. Braze Welding

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Braze welding is a technique that involves using a special clamp or braze to secure the material being welded. With this, you can create welds from metals such as iron and steel. However, before you start doing this, you need to know some basic concepts concerning Braze welding.


Finishing up is the most critical time as that is when cracking is most likely to occur. Properly heating your piece is of course important but it’s the cooling portion of welding that’s even more important. 

When You Want To Weld In-House

It’s very possible to perform your welding in-house as long as you take your time and follow the steps above. We find that most mistakes occur when steps are missed or ignored. Save yourself the frustration and stick to the directions.


This term simply refers to adding pressure to heated metal. To better bond the metal or for straightening purposes. The purpose of this is to make the weld bead thinner. This reduces any further stress to the welding joint. 

Peening can be performed forma tool such as a chipping hammer, air gun, descaling gun or drilling tool using multiple flaps.

Post-Weld Heating

Post weld heating refers to heating a cast iron product after welding it. In the most common case, post-weld heating is used to remove the excess weld metal that is left on the metal being welded. The process also differs depending on the method of heating that is used. For example, some post-weld heaters rely on a torch, while others can be electrical.

Which Welding Rods Can be Used? 

99% Nickel Rods

99% Nickel is a special blend of Nickel, Copper, Molybdenum, and Zinc, which is a combination that is used often in welding applications. While 99% Nickel has been around for many years, it is only recently that this blend has become more popular, thanks to the current state of the economy. Why? Because 99% Nickel is an all-around welding rod that is also cost-effective.

55% Nickel Rods

55% nickel is much like the 99% variety except it is more economical. It works extremely well for welding cast iron sections.

Steel Rods

Although you can use steel rods, these are best suited to minor repairs. Steel rods are the cheapest option you should use for this application.

Frequently Asked Questions

Can Cast Iron Be Stick Welded?

Can Cast Iron be stick welded? Yes, it can. In fact, this method is probably used by more DIYs than any other welding method. It’s an effective way to make a repair especially if you are not at an expert welding level.

Can Cracked Cast Iron Be Repaired?

A cracked cast can certainly be repaired.  In some cases, you don’t even have to worry about welding. 

Naturally you can perform a metal brazing technique, but in some cases, you can also use a variety of epoxy putties or even cold metal stitching to make a repair.

Why Is My Cast Iron Seasoning Pan Cracking?

A cast iron seasoning pan can crack for any number of reasons, but it’s most due to being used in high heat situations. Cast iron pans can literally last for decades if they are properly cared for. 

Whether it’s used in a stovetop or oven, cast iron will definitely wear down because of high temperatures. Just think about it; To suddenly throw a cast iron pan into a 400-500 degree stove all the time puts quite a bit of stress on it. Naturally, they can be repaired even without welding in some cases by following the recommendation above. 


How do you weld cast iron? Now you know. We hope you enjoyed this article. As you now can tell, welding cast iron requires a bit of prep time and patience. But once you get the hang of it by following our steps above, you should be cast iron welding in no time. Happy Welding!


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