How to Refinish a Cast Iron Sink: A Step-by-Step DIY Guide
Learn how to refinish a cast iron sink with Bondo and Rustoleum. Step-by-step DIY refinishing guide with before-and-after photos.

Antique high-back kitchen sinks bring timeless charm to any home, but years of wear can leave them looking far from their best. Instead of replacing a vintage piece, why not restore it? My husband and I recently learned how to refinish a cast iron sink and were able to transform it into a stunning focal point for our kitchen.
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In this post, I’ll walk you through how we repaired dings and dents using Bondo and gave the sink a smooth, shiny new enamel surface using the Rustoleum Tub and Tile Refinishing Kit. With a little elbow grease and patience, you can breathe new life into your antique sink, too!

Why I Chose to Restore This Sink
I’ve always dreamed of having a vintage sink like this in my kitchen. When I came across this one on Facebook Marketplace for such a great price, I just couldn’t pass it up. For its age, it wasn’t in terrible shape, but it definitely showed years of wear with rust, stains, and a few dings.
The character and charm this antique high-back sink will bring to my kitchen are truly invaluable to me, and that’s why I knew I had to learn how to refinish a cast iron sink. I wanted to preserve its history while giving it a fresh new life—and I couldn’t be happier with the results.
Why Refinish an Antique Cast Iron Sink?
Antique sinks are built to last but often show their age with chips, stains, rust, and general wear. Restoring one not only saves money but also preserves the craftsmanship and character of a bygone era. Whether you’re tackling a family heirloom or a vintage flea market find, refinishing can restore its beauty and functionality.
Materials You’ll Need
Here’s what we used to refinish our sink:
- Bondo All-Purpose Putty (for dents and dings)
- Sandpaper (400-grit and 600-grit)
- Painter’s tape
- Plastic sheeting or drop cloths
- Rustoleum Tub and Tile Refinishing Kit
- Non-abrasive cleaner (or Rustoleum Surface Prep Cleaner)
- Scrubbing sponge
- Foam roller and small foam brush
- Disposable mixing container (for Bondo and refinishing paint)
- Gloves and a mask
Step 1: Preparing the Sink
Preparation is the most important step in ensuring a smooth, durable finish. Here’s how we prepped our antique sink:
1. Thoroughly Clean the Surface
We started by scrubbing the sink with a non-abrasive cleaner to remove years of grime, rust, and stains. For stubborn spots, a little extra elbow grease with a sponge worked wonders.
2. Repair Dents and Dings
Our sink had several dings and gouges in the cast iron surface. To fix them:
- We mixed the Bondo All-Purpose Putty according to the package instructions.
- Using a putty knife, we applied the mixture to the damaged areas and smoothed it out as much as possible.
- Once the Bondo cured, we sanded it with 400-grit sandpaper to create a seamless surface.
3. Sand the Entire Sink
Next, we sanded the entire sink with 400-grit sandpaper to roughen the surface, which helps the refinishing paint adhere properly. For particularly smooth spots, we went over them with 600-grit sandpaper.
4. Tape and Protect Surrounding Areas
We taped off the edges of the sink and covered nearby surfaces with plastic sheeting to prevent any stray refinishing paint from landing where it shouldn’t.
Step 2: Applying the Rustoleum Refinishing Kit
The Rustoleum Tub and Tile Refinishing Kit is perfect for giving sinks a glossy, durable finish that mimics new enamel. Here’s how we applied it:
1. Mix the Refinishing Paint
The kit includes a base and activator that need to be mixed thoroughly in a disposable container. Make sure to wear gloves and a mask during this step, as the fumes can be strong.
2. Apply the First Coat
Using a foam roller, we applied a thin, even coat of the refinishing solution. For corners and tight spots, a small foam brush came in handy. Be sure to work quickly—the paint starts to set fast.
3. Apply Two More Coats
After letting the first coat dry for about an hour, we applied two more thin coats for full coverage and a smooth, glossy finish. Each coat dried for about an hour before the next application.
Step 3: Curing and Finishing Touches
Once the final coat was applied, the sink needed to cure for three full days before it could be used. This waiting period is essential for the refinishing paint to set properly and achieve maximum durability.
After the curing period, we carefully removed the painter’s tape and gave the sink a light wipe-down to remove any dust. The result? A beautifully restored sink that looks brand new!
Before and After Photos: A Stunning Transformation

Before: The sink was covered in rust, discoloration, and years of wear.

After: The sink now shines with a bright, glossy enamel finish, ready to take center stage in our kitchen.
Tips for How to Refinish a Cast Iron Sink Successfully
- Don’t Skip the Prep Work: Proper cleaning, sanding, and taping are critical for achieving a smooth, durable finish.
- Work in a Well-Ventilated Area: The fumes from the Bondo and refinishing kit are strong, so open windows and use fans if working indoors.
- Be Patient with Curing: It’s tempting to use the sink right away, but waiting the full three days ensures the finish will last.
- Use Thin Coats: Thin, even coats prevent drips and streaks in the final finish.
Why This Project Was Worth It
Learning how to refinish a cast iron sink took time and effort, but the results were well worth it. It saved us money compared to purchasing a brand-new sink and allowed us to preserve a beautiful piece of history. Plus, there’s something deeply satisfying about tackling a DIY project like this and seeing the transformation firsthand.
If you’re considering learning how to refinish a cast iron sink, I hope this guide gives you the confidence to take on the challenge. It’s a project you’ll look back on with pride every time you use your sink.
Our DIY Farmhouse Journey
We’ve been DIYing this old farmhouse into our dream home, and this sink restoration is just one of the many projects we’ve tackled. Every project brings us closer to creating a space full of character and charm. Here are a few of our favorite DIYs so far:
- How to DIY Farmhouse Crown Molding
- DIY Peg Rail & Mudroom Reveal
- How To DIY Simple Farmhouse Board & Batten
We hope these projects inspire you to add a personal touch to your own home!
