How to Fix Cast Iron without Welding

How to Fix Cast Iron without Welding?

Cast iron appliances are easily some of the most durable ones out there. They are extremely reliable and sturdy and tend to be very durable too. However, due to their hardness, they are also very brittle, meaning they are prone to cracking. The other ways of bonding metal to metal without welding might not work here.

The most common practice for fixing cast iron in welding, but that requires special skills and tools. If you are facing a cracking problem with your cast iron product and handy with light tools, this guide will show you how to fix cast iron without welding.

Step-by-Step Guide to Fixing Cast Iron without Welding

The easiest way to fix cracks on your cast iron product is with epoxy putty. For cast iron, try to get a steel-reinforced, cold weld epoxy. They generally come in tubes. You will need one tube of epoxy resin and one tube of hardener.

Step 1: Choosing Your Epoxy

You need to choose your epoxy according to the application of the cast iron product you want to fix. Regular epoxy will resist temperatures up to 270º-300º F. If you use the cast iron product for heating, get heat resistant ones.

Step 2: Clean Your Cast Iron Product

The cast iron may have rust buildup around the cracks. This will hamper the application of epoxy. Any dirt and pollutant will also make the repairing process harder. So, you will need to clean it up really well first.

  • Put on some disposable latex gloves and your safety goggles
  • Use coarse grit sandpaper (80 100 grits) to scrub off any rust and dirt
  • Use a straight-line motion to sand the rust, as a circular motion can worsen the crack
  • Wash the cast iron item well with soapy water to get rid of all the loose particles and rust bits
  • Dry the cast iron product overnight or by using heat
  • With a steel scrub pad or a stainless steel brush, clean the area near the cracks, so all lodged particles are well and loose

Now the cracked area is clean and free of any small granules that could disturb the repair.

Step 3: Preparing the Epoxy

At this stage, you will need to prepare the epoxy to be applied to the cracks. To do this, follow the process mentioned below.

  • Get a small piece of cardboard or a plastic sheet about 3” × 3” to prepare the epoxy
  • Read the instructions on the epoxy tube or the packet carefully if you haven’t worked with it before
  • Use equal parts of epoxy resin and the hardener to create as much putty as you require
  • Mix it well with a putty knife or a small stick

Step 4: Preparing Your Cast Iron Product

Now, you will have to get your cast-iron appliance ready for the repairing process. This means that if the cracked part completely came off from the main body, you will need to find a way to keep it in place. Make sure that you keep just a sliver of space in between so the putty can get in.

You should look to use tapes or clamps to keep the pieces together for the best results. If that isn’t possible, you can also use some kind of glue that is not water-based. Use as little as possible to make sure the broken piece doesn’t get detached.

Step 5: Apply the Epoxy Putty

Use your putty knife to apply the epoxy putty over the cracked area. Slowly apply a little bit of pressure to help the epoxy get into the cracks.

Once you think that enough epoxy has reached into the cracks and there is a good layer of epoxy over the crack on all sides, you can scrape off the excess putty with your putty knife.

Step 6: Use Fiber to Strengthen

If the product is meant to be carrying weight along the cracked area, you will need to strengthen the epoxy bonding with fiber weaves. The most popular fibers to use for these types of repairs are fiberglass, Kevlar, carbon fiber, etc.

After applying the epoxy, while it’s still wet, you will need to apply the fiber on top of the first epoxy layer along the direction the load will be distributed. A good rule of thumb is to apply the fiber perpendicular to the crack.

And after laying down the fiber, make sure it fits the curvature of your cast iron product well. Then finally, apply another layer of epoxy over the fiber to make sure it locks in with the product.

Step 7: Drying the Epoxy

You need to make sure that you have dried the epoxy completely before you can start using your cast iron product. Keep the product in a secluded space, away from children and pets, to dry out over at least 2 days.

Step 8: Finishing Touches

The cast iron product is almost ready to be used again. Yet, it will still feel a little bit sticky. You can use some paint thinner and apply it over the epoxy with a piece of cloth, and it will take away the sticky feeling.

But there will be an increase in its thickness around the cracked area due to the epoxy layer and the fibers. There may also be tiny bits of hardened epoxy sticking out over the corners.

You can file out protruding excess bits with a filer to get an even plane where needed. And you can sand out the outer bumpy bits on the epoxy to get a smooth finish. Be careful not to whittle down to the fibers as they provide the structural strength.

Finally, you can apply some color to hide any imperfections that may be noticeable otherwise.


With this detailed, step-by-step guide, you now know how to fix cast iron without welding. This will surely help you to repair cast iron items that you haven’t been able to use because of a crack, without owning any welding equipment or training. Try this method and get started on fixing cast iron things around the house.

We have also described the patch panel installation process without welding. It can be handy if you don’t have a welding machine.

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