How to Create Terrazzo Effects with Jesmonite® AC100 Eco-Resin
Terrazzo is one of the most popular techniques for creating unique Jesmonite® projects. By incorporating colorful chips into your mix, you can create everything from trays and coasters to planters, candle holders, and home décor pieces that look completely custom.
One of the best things about terrazzo is that it can be as sustainable as it is beautiful. Whether you're repurposing leftover material from previous projects or creating custom chips from scratch, terrazzo is a great way to reduce waste while adding visual interest to your work.
What is Terrazzo?
Terrazzo is a decorative technique that combines colorful chips, known as aggregate, within a solid surface. Traditionally, terrazzo was made using marble chips embedded in cement, then ground and polished to reveal the pattern beneath. Today, terrazzo-inspired designs are popular in home décor, furniture, countertops, and handmade crafts because of their unique, playful appearance.
With Jesmonite® AC100 Eco-Resin, you can create your own terrazzo chips in any color, shape, or size. These chips are mixed back into fresh Jesmonite® and cast into molds, creating one-of-a-kind patterns that are revealed through sanding. Better yet, leftover Jesmonite® from previous projects can be repurposed into terrazzo chips, making it a creative and sustainable way to reduce waste.
Method 1: Repurpose Leftover Jesmonite® Using Silicone Mixing Cups
This is our favorite method because it creates virtually zero waste while building a collection of terrazzo chips for future projects.
Step 1: After pouring your project, don't throw away the leftover Jesmonite®.
Step 2: Spread the remaining material into a thin layer inside your mixing container.
The thinner the layer, the better. Thick layers create large chunks that can be difficult to break apart and use in terrazzo projects. Thin layers produce chips that are easier to crush and incorporate into future mixes.
Step 3: Allow the material to cure completely.
This leftover material also serves as a handy "terrazzo timer." When the thin layer of Jesmonite® becomes dry enough to crack and release from the sides of the container, it's typically a good indication that your cast project is ready to demold as well.
Step 4: Remove the cured material and break it into chips.
Break the material into a variety of sizes to create a more natural terrazzo effect.
Step 5: Store your chips in a jar or container.
Over time, you'll build a collection of colors from previous projects that can be mixed together to create unique terrazzo designs.
We've found that silicone mixing cups work best for this process because the cured Jesmonite® releases easily without sticking. After years of testing different styles, our team eventually settled on these triangle silicone mixing cups as our favorite. Their flexible design makes it easy to spread leftover material into a thin layer, remove cured chips, and keep the process mess-free.
Fun Fact: The terrazzo table shown below was cast by our team using nearly a year's worth of leftover Jesmonite® collected from previous projects. By saving a little material from each pour, we were able to cast this adorable terrazzo table while ensuring virtually nothing went to waste.
Method 2: Create Custom Terrazzo Chips
Want complete control over your terrazzo colors? Creating chips specifically for terrazzo projects allows you to build a custom palette and ensure you always have the colors you need on hand.
Step 1: Mix a small batch of Jesmonite® AC100.
You don't need much material for this process. Small batches are perfect for testing new pigment combinations or creating accent colors for future projects.
Step 2: Add your desired pigment color.
This is a great opportunity to create colors you may not typically cast with, such as bold accent colors, pastels, or seasonal palettes that will stand out in your finished terrazzo piece.
Step 3: Pour the mixture onto a silicone mat or sheet of parchment paper.
Spread the material into a thin, even layer using a spatula. As with Method 1, thinner is better. Thin sheets are easier to break into chips and create a more refined terrazzo appearance.
Step 4: Allow the material to fully cure.
Once cured, the sheet should easily release from the silicone mat or parchment paper.
Step 5: Break the sheet into chips.
Snap the cured material into a variety of sizes and shapes. Using a mix of large and small chips creates a more natural, dynamic terrazzo pattern.
Step 6: Build your terrazzo library.
Store your chips in labeled containers or jars so you can easily mix and match colors for future projects.
One of the biggest advantages of this method is consistency. If you're creating a collection of products or working with a specific color palette, making custom terrazzo chips allows you to recreate the same look again and again.
Casting Your Terrazzo Project
Once your terrazzo chips are ready, it's time to cast your final piece. The process is very similar to any standard Jesmonite® AC100 project, with a few additional considerations to ensure your terrazzo pattern looks its best.
Begin by measuring and mixing your Jesmonite® AC100 at the recommended 2.5:1 ratio of base to liquid. Mix thoroughly until smooth and lump-free. Once your base mixture is ready, gently fold in your terrazzo chips. The amount you add is entirely up to you and the look you're trying to achieve. For a subtle terrazzo effect, a light sprinkle of chips may be all you need. For a bold, chip-heavy design, terrazzo aggregate can make up as much as 80% of the mix.
When pouring into your mold, pay special attention to the first layer. Terrazzo chips create small gaps within the mixture, which can increase the likelihood of trapped air bubbles. Before filling the mold completely, take a moment to ensure the first coat of Jesmonite® is fully coating the mold surface and has settled into all the details. Gently tap or rotate the mold as needed to help release trapped air and create a smooth face on the finished piece.
Once you're confident the front surface is fully covered and bubble-free, pour the remaining mixture into the mold and level as needed. Allow the Jesmonite® to cure completely. As with any AC100 project, you'll know it's ready to demold when the material has cooled and returned to room temperature.
After demolding, the terrazzo pattern will still be hidden beneath a thin layer of Jesmonite®. The next step is sanding, where the chips are gradually revealed and the terrazzo effect comes to life.
Sanding to Reveal the Terrazzo Pattern
This is where the magic happens. After demolding, most of your terrazzo chips will still be hidden beneath a thin layer of Jesmonite®. Sanding removes that top layer and reveals the colorful aggregate underneath.
We recommend wet sanding whenever possible to keep dust to a minimum. All you'll need is a bucket of water, sandpaper, and a sanding block or detail sander. A sanding block works especially well for flat surfaces, while a detail sander can help reach grooves, edges, and intricate mold details.
For the easiest sanding experience, begin shortly after demolding while the Jesmonite® is still relatively soft and hasn't reached its full strength. The material sands much more easily at this stage, allowing you to expose the aggregate with less effort. If you're unable to sand right away, don't worry. Jesmonite® can be sanded at any point after demolding.
Start with a more aggressive grit, such as a 120 or 180 grit sandpaper, to quickly expose the terrazzo chips. Once you've achieved the desired amount of aggregate exposure, work your way through progressively finer grits. We typically finish with 300 to 400 grit sandpaper for a smooth, refined surface.
So how do you know when you're done sanding?
Whenever you like the way it looks.
There is no right or wrong answer. Some creators prefer just a few chips peeking through the surface, while others continue sanding to reveal a dense terrazzo pattern. The more you sand, the more aggregate you'll expose. Stop when you've achieved the look you're after and you're happy with the overall balance of color, texture, and pattern.
Finishing Your Terrazzo Project
We highly recommend sealing your terrazzo projects at least 24 hours after sanding.
After you've revealed the aggregate and achieved your desired finish, you'll notice the surface may appear chalky or dull. Don't worry, this is completely normal. Sanding exposes fresh Jesmonite® and temporarily mutes the colors within the piece.
Once a sealer is applied, the colors and terrazzo chips come back to life. You'll see increased color vibrancy, improved depth, and a more finished appearance overall.
Sealing also helps protect your project from UV exposure, water, stains, and everyday handling, making it an important final step for both appearance and durability.
It's a win-win. Your project looks better and performs better.
For complete guidance on Jesmonite® sealing products, including recommendations for different applications, download our FREE Jesmonite® Ancillaries User Guide.
