How to Use Thin Set or Paint for Your Mosaic Background

Creating a mosaic is not just an art project—it’s a deeply satisfying way to piece together beauty, one tiny tile at a time. Whether you're new to mosaics or looking to try a new technique, this guide will walk you through what you need to know about using thick paint or thin set for a background to your mosaic - instead of tiles - and it’s fun, too!

Let’s talk about designing a beautiful mosaic on a Multi-Art Backer that is 1/4” thick, using stained glass or tile, and then finishing it off with a colorful thin set or painted background for a truly unique look.

🧰 Materials You’ll Need:

• Wooden backer board (try our Multi-Art Board 1/4” thick)
• Stained glass, ceramic tiles, or glass tiles, and more - your choice
• Wheeled glass nippers (for shaping tiles)
• Weld bond glue for interior mosaic
• Powdered Thin set mortar
• Powdered cementious oxides or liquid tints for coloring your thin set
• Trowel or spatula
• Safety gear (gloves, goggles, mask)
• Pencil or chalk for sketching your design

After you have your materials, here’s the next steps.

🌸 Step 1: Plan Your Design

Start by sealing your board with 1/2 weld bond and 1/2 water mixed together and brushed on front and sides. Let dry - approximately 60 minutes. You can also apply a  gesso primer to help paint stick to the board.

Next, lightly sketch the shape of your design on the wooden backer with pencil or chalk. Don’t worry about fine detail—just capture the basic shapes. This will guide your tile placement.

Tip: Simple designs like daisies, tulips, or sunflowers work beautifully for beginners!

✂️ Step 2: Cut and Arrange Your Tiles

Choose your materials. You can use:

• Stained glass – Beautiful for delicate shading and vibrant color.
• Glass tiles like Kismet tiles.
• Ceramic tile – Durable and great for bold, blocky shapes.
• Vitreous glass tiles – Pre-cut and perfect for uniform looks.
• Use whatever you enjoy working with!

Use your wheeled nippers to cut tiles into smaller shapes and arrange them inside your design. Adjust as needed until you're happy with the layout.

🧴 Step 3: Glue Your Tiles Down

Once you’re happy with the placement, it’s time to adhere the pieces. You can adhere your tiles as you go if you wish. Either way is fine.

Recommended adhesives for wood:

• Weld bond – A go-to PVA glue for indoor mosaics on wood.
• Thin set mortar – Provides a super-strong hold but may be harder to work with for beginners.
• Mosaic-specific adhesives – Like DAP Weldwood or Loctite Power Grab for small pieces.

Apply a small amount of glue to the back of each tile and press it into place. Let the design fully dry (typically 24 hours).

🎨 Step 4: (Option 1) Create the Background with Colored Thin Set

Now here’s where it gets really fun! Instead of traditional grout, you can use colored thin set to create a seamless, artistic background around your subject - really nice as it adds texture too.

Here’s how:

1. Add powdered thin set mortar into a mixing container and then add your powdered pigments (like cementious oxides). Add a little water and mix well to get your desired background color. Use white thin set if you want light-colors; otherwise use gray thin set for darker colors, especially black.
2. Spread the thin set on the wooden backer around your design using a spatula or tile trowel. Apply it like you're frosting a cake, pushing it right up to the edges of the tiles.
3. Texture or smooth it as you go. You can leave it smooth for a sleek look, or add a textured pattern using a comb, brush, or sponge for dimension.
4. Let the thin set cure completely—usually 24 to 48 hours. Don’t rush this step!

🎨 Step 4: (Option 2) Create the Background with Colored Paints

If you want thick, textured paint on a wood backer, acrylic paint or oil paint are the best options, depending on your preference:

Acrylic Paint (Heavy Body or Impasto Medium)

• Pros: Dries faster, easy to layer, water-based (easy cleanup), durable.
• Best Option: Heavy body acrylics or acrylic impasto medium mixed with regular acrylics for added thickness.
• Application: Use a palette knife, thick brush, or even a textured roller for deep texture.

Oil Paint (For Rich, Deep Texture)

• Pros: Longer drying time (more blending time), rich depth of color.
• Best Option: Use cold wax medium, impasto gel, or just straight thick oil paint.
• Application: Palette knives work best for deep texture.

Additional Tips:

• If using acrylics, consider modeling paste or texture gels for extreme thickness.
• If using oils, consider cold wax medium for sculptural texture.
• A gesso primer helps the paint adhere better to the wood panel.

🌟 Final Thoughts

Using colored thin set or thick paint as a background gives your mosaic a bold, painterly effect that adds real character. Combine that with the sparkle of stained glass or the earthy feel of ceramic, and you’ve got a one-of-a-kind piece of art.🌸