How to Repair Cast Iron With Putty

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Things You'll Need

  • Epoxy putty (JB Weld, Quick Steel)

  • Dish soap and rag

  • Sandpaper (80-grit)

  • Cardboard scrap

  • Putty knife

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Cast iron is a useful material that is used in a variety of ways from stoves to engines. It is a hard but often brittle material that can crack if dropped, and it is also prone to rust if not cared for. Cast iron should be kept in dry conditions to avoid rust. However, if it does become damaged over time, it can be repaired without too much effort or time.


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Step 1

Purchase a tube of epoxy putty such as JB Weld or Quick Steel at your local hardware store. These types of epoxies act as glue that will adhere to cast iron, filling the crack with a safe seal.

Step 2

Sand the cast iron with 80-grit sandpaper to remove rust and paint that may be covering the crack. Use a back and forth motion rather than circles to avoid a widening of the crack.


Step 3

Use dish soap, water and a rag to clean out the crack and surrounding surface area. Allow to dry completely before continuing.

Step 4

Stir the epoxy according to the manufacturer's instructions. Squeeze some out onto a flat surface, such as a scrap of cardboard, and use a putty knife to mix it.


Step 5

Spread the putty into and over the crack. Scrape off any excess with the putty knife before it dries. Wait a full 24 hours before handling your cast iron item.

Step 6

Paint over newly sealed crack to match the rest of the cast iron item, if desired.


If some of the putty accidentally gets on the non-cracked surface, you can wait a day for it to dry and simply sand it off.

If the crack is deeper than 1/4 inch, put putty on in layers, allowing each layer to dry for a day before continuing.