Faux Green Leaf Mosaic Using Air Dry Clay and Acrylic Paints

I've used stencils to create raised layers on my mixed-media art, and I've wondered if I can create a faux mosaic using a similar principle.

In order for my design to look more like a mosaic, I need the surface to be higher than a normal stencil would help me create. Through some trial and error, I learned I could use air-dry clay with a stencil cut from 1/8" thick acrylic to create the look I'm after. I tested chipboard, hardboard, modeling paste, plaster of Paris, and a combination of different materials and techniques before I landed on air-dry clay and acrylic. 

I've never used air-dry clay before, so this was a learning process. Come learn with me as we create a faux green leaf mosaic.

Materials:

• 1/8" thick acrylic sheet
• 6" x 8" wood cradleboard
• Acrylic paint in various tints and shades of green
• Mod Podge Matte
• Air-dry clay
• Polycrylic
• White grout
• Water to mix with grout

Tools:

• Illustrator or other design program
• Laser cutter
• Paint brushes
• 220-grit sandpaper
• Palette knife
• Nitrile gloves
• Sponge or clean-up cloth

Planning my Leaf Design

It's summer and I see plenty of green leaves shaking on trees on my daily walks with my dog. This gave me my idea for my design. Because a mosaic is created from cut or broken pieces of tile or pottery, I thought doing a relatively simple leaf design that I cut up into smaller shapes would work. 

I chose a maple leaf to give me more to work with. A maple leaf is wide, so I thought a swirl of wind going up and down would take up the vertical space of my cradleboard. Then to make the leaf the center of attention, I thought a radial design (which I see on a lot of mosaics) behind it would be good. And then I would just fill in the rest of the space with various shapes and a border around the edge. 

My cradleboard is 6" wide by 8" tall, so I will start with a rectangle 5.98" wide by 7.98" tall so my design sits just inside my art surface. 

I decided I would draw everything as solid shapes and cut them all with the eraser tool in Illustrator sized at 6 points wide. If you double-click the eraser tool in your tools panel, you can change the size (see second photo above). I design a lot for the laser cutter and prefer the thickness of wood sections to be at least 2mm wide to ensure the design is pretty sturdy. I kept this same philosophy for the acrylic. That's why I chose a 6-point thickness for the eraser tool.

Drawing It Out

I drew the leaf first, then cut it up with the eraser tool. I kept a dot that's 0.09" in diameter (slightly more than 2mm) and one that's 3/8" in diameter on my artboard to help me cut up and adjust the pieces (see third photo above). The larger dot ensures I don't make my faux tile pieces too small to fill with clay. The smaller dot is my guide to make sure the stencil lines are going to be sturdy when they are cut.

Next, I drew the wind swirl and cut that up in the same way. Then I drew concentric circles coming from the center of the leaf. I drew them as circles with thick stroke lines (about 3/8" thick) and no fills. I used my 0.09" dot to make sure they were spaced appropriately apart. Then I went to Object --> Expand to turn them into solid fills that I could cut with the eraser tool. I aimed to offset the cut lines on each circle to create interest in the design (in the same way bricks are offset on a wall).

Then I added a border. I started with tiny squares in the four corners. They were much smaller than 3/8" but I decided to take the risk. Then I doubled the length of the square on the top left to form a rectangle the same height as that square. I spaced it away from the square using my 0.09" dot. I created a similar rectangle on the opposite side and did some quick math to decide how many I should put along the top and allow for even spacing between them. 

I used the blend tool in Illustrator to quickly fill in that line. Double-click on the tool in the tools panel, choose Specified Steps in the Spacing drop-down, select 9 for the number of rectangles to fill the space with, then hit OK. Then click the rectangle on the left, connect it to the one on the right, and you get evenly spaced rectangles all the same size. Finally, choose Object --> Expand to create solid pieces. I performed a similar process to fill in the border on the vertical sides.

Now all that was left was filling in the remaining space. I drew slightly wavy lines with thick strokes (about 3/8" tall) horizontally across the whole length of the cradleboard, using my 0.09" dot to space them out. Then I expanded them to create fills I could cut with my eraser tool. I adjusted corners and sizes as needed to make sure I didn't make pieces that conflicted with the focal point of the design and also to make sure I wasn't making tiny pieces that I'd have difficulty filling with clay. 

Creating the Stencil

All of this created the mosaic design I wanted in the end. However, to create the stencil, I needed the reverse of this design. 

I grouped everything together. I then drew a rectangle 6.5" wide and 8.5" tall. I put it behind and centered it vertically and horizontally with the design. I created a copy so I didn't lose the original, and used Minus Front from the Pathfinder tool to create the negative that I will cut from acrylic. 

I saved that as a separate SVG and DXF file (provided below), and headed off to my maker space to cut it from acrylic. I ran a few test cuts first because I rarely cut acrylic. I wanted to make sure I wasn't using too much power because I didn't want to remove more material than was necessary. Then I cut it.

I buy my cradleboards from Blick, so they are usually nice and smooth with no sanding required. If you are using any other wood surface, make sure it's sanded smooth to make it easier to paint and adhere the clay to. Make sure the surface is clean, as well. 

When your surface is smooth and clean, paint the whole thing a solid color, sides included. I painted mine white to match my grout color but you could paint it black to create a nice contrast or a color that matches the green faux tile pieces you are going to create. Let it dry and sand it lightly with 220-grit sandpaper. Then dust it off to make sure there's no paint residue.

Please note, this is going to take a while. You're looking at 7-10 hours total depending on how much you fill the spaces. As you work, you will likely get faster and develop a rhythm, but we're still talking about a long day. You can break this up over several days if you need to. Just pack up your unused clay each time you work on the project so it doesn't dry out. 

Basic Tips

• Keep it from drying out: To keep the clay from drying out while you are using it, cut off a small chunk with a butter knife or palette knife. Only use a little at a time. Put the chunk in a bowl or on a silicone mat (nothing that will soak up moisture), and cover it with a wet washcloth. Keep a water bottle nearby to spritz the washcloth if it starts to dry. Fold the rest of the clay back inside the wrapping, and put it inside a zipper closure bag with all the air squeezed out so it doesn't dry out. I also wrapped the opened end with cling wrap just to be extra safe. You'll probably want to find more air-dry clay projects to make with it soon because we won't be using a lot of it for this project.
• Keep the stencil in place: Because I made my design go right up to the edge of the cradleboard, I placed the stencil carefully on top and used a weight to keep it in place. This meant I would need to fill in what I could get to, then let the clay dry a while before removing the weight to fill in the rest. 
• Glue: Another thing I learned from several of my trial-and-error attempts is that the air-dry clay won't stick permanently to the painted wood. So, I kept a container of Mod Podge Matte, a tiny paintbrush, and a small dish of water nearby. Before I smashed clay into a hole in the stencil, I'd dip the paintbrush into the Mod Podge, paint it onto the wood below where I was going to put the clay, rinsed the brush clean in my dish of water to keep the glue from drying on the brush, and wiped it on a paper towel. You don't have to fill the whole space with glue, just enough to keep the clay in place in the middle. Try to avoid getting glue on the cut edges of each hole. Also, make sure to put the lid back on the Mod Podge so it doesn't develop a skin on top while you are working with the clay.

Let's Get to Work

Start by making sure your work surface and hands are clean. Paint Mod Podge into a hole, and then pinch off a small piece of clay to mash into the hole. I put a lump of clay in the middle of each hole and pressed it down and out to fill in the space.

I used my fingernail to spread the clay out to the edges of each hole, but you can also use a palette knife or a clay carving tool. You just need something to push the clay into tight corners. If any clay goes over the sides of the holes, use the palette knife to cut it away. The goal is to fill the holes completely, but not overfill them. The clay can puff up if you want but not out, because it will be difficult to remove the stencil without breaking the faux tiles if they go over the sides of the holes. 

Because it's hard to know how much clay is needed to fill the holes, I pinched little bits off at a time from the chunk in the bowl and added the bits to the holes a little at a time until they were filled. I used my fingernail (or you can use your palette knife) to scrape away excess and smooth over the top so there weren't obvious lumps and lines.

After a while, I started putting glue in 2-3 holes at a time, pushing lumps of clay into each just to cover the glue to keep it from drying, then going to work filling in each space fully. This helped the process go faster, but only time would tell if the clay would actually stick to the wood surface when everything was dry.

By the time I finished all the areas not covered by the weight, the top pieces of clay were dry. This meant I could just remove the weight and keep going. I had previously thought I would have to wait for the clay to dry first, but a lot of it was already dry enough to hold the stencil in place.

When I completed the whole design, I let it dry overnight with the stencil still on top. I left the stencil in place because as the clay dries, it shrinks away from the sides, making it easier to remove the stencil without moving the tiles.

The next day, I removed the stencil. This was a big mess and a lesson learned, but not a total disaster.

First I pressed down on the tiles to make sure everything was completely dry. If you press on the tiles and they have any give at all, they are not completely dry. The thicker they are, the longer they take to dry all the way through. The good news is, these tiles aren't thick like a figurine, so they don't take long to dry. Overnight was all they needed.

Then came the mess. I had noticed some of the glue seeping beneath the stencil while I was mashing clay into the holes, so I was concerned the stencil might have glued itself to the wood. I lightened up on the glue for the lower half of the stencil after I saw what was happening, but the stencil was still glued to the board on top. In hindsight, I now know I shouldn't have taken the risk with smaller holes in the design. It was near impossible to not get glue close to the edges in those tiny areas. If I were to do this over again, I would redesign to make all the holes bigger like those in the leaf and wind swirl. 

So, I began lifting the stencil carefully around the outside edges and hearing the cracks as it released itself from the wood. It felt like I was releasing ice from a plastic ice tray. I didn't have as hard a time removing the stencil in the lower part of the design. But the closer I got to the top of the art, the stencil itself started to crack. 

I used a palette knife to pry the stencil away from the wood without doing too much damage to the tile pieces. I even used a needle to poke under the stencil in the thin areas to weaken the bond of the glue there. Slowly but surely, and in many pieces, I got the stencil out. The stencil is broken into several pieces and unusable now, but I can cut another if I want to use it for a different project.

A few of the tiles broke, came off, or stuck to the stencil. I used a palette knife to remove the pieces from the stencil without damaging them by pressing a flat edge against the back and outside edges of the tiles. Then I glued the broken and missing pieces back to the wood. There were only a few that needed to be glued back on, so I count myself lucky.

I left the glue to dry for two hours, then I sanded the tiles lightly with 220-grit sandpaper. I wanted to soften rough edges, get rid of raised sharp points, and make the surface smoother for painting. I have flexible sandpaper, so I was able to fold it easily to get between the tiles. 

When I was done, I blew away the dust from several directions and wiped a clean cloth across it gently to remove any extra debris.

Painting With the Greens I Have

My original design gave me an idea of how I wanted to separate the greens so you can see the design best, but after looking at the green paints I have, I went back and changed the colors in my illustration to work with those. 

When choosing what colors go where, you will want to stick with only a few values of a similar green. You don't want a teal going alongside a lime near a kelly green. You want them to be harmonious. Sometimes this is easily fixed by mixing one color with all the rest, so you will have a variety of tints and shades that work together. Or you could just have a dark and medium green that work together, and mix white with the medium green to get lighter variations of it.

You want to mix light and dark values in your design to allow the leaf to stand out. I have 4 values: a light, 2 mediums, and a dark. I decided to make the leaf the darker of the mediums and the wind swirl the lighter of the mediums so you know those are connected. The big circle behind the leaf is the lightest value which helps the leaf really stand out. Then a dark background brings the lighter values forward. And the border is the same medium green as the leaf to wrap up that connection and add strength to the attention on the leaf.

Start Painting

With my paints ready, I decided to start with the leaf and work out toward the edges. I left my design up on my screen to refer to it as I painted. 

I have three sizes of paintbrushes to work with. They are all small, but I used the largest of the small ones for the bigger tiles, and the tiniest one for the border pieces and other really small pieces in the design.

It's OK to let the paint go down the sides on all the inside tiles because the edges will be covered with grout later. But be careful on the outside edges of the border since those may show. If you need to, after you apply the grout in the next step, you can get your white paint and touch up the sides after everything is dry.

Seal the Paint

To make certain the grout doesn't stick to the tiles and to make them look extra glossy like actual tiles, I decided I should put a couple of clear gloss coats on top of the paint. I used a wide brush and slapped the polycrylic on. I didn't care if it went over the edges of the tiles into the channels between them. It's clear for one thing and will get covered up by grout later anyway. I did turn my brush perpendicular to the board to brush between the tiles and thin any puddles that had formed. I also sealed the sides of the cradleboard. 

After an hour, I very lightly sanded the tops of the tiles with 220-grit sandpaper. I just wiped it across the surface like I was wiping it with a soft cloth. Then I painted another coat of polycrylic and let it dry overnight because it was late. If you are working on this during the day, it should be ready to go after two hours. Sand it lightly again, and then we can grout.

I've never worked with grout before and the instructions said to mix it with water until you get a putty-like consistency. That doesn't mean much to me, so I headed to YouTube to find out what that means. I needed a visual of what I'm working toward. 

I found this video that not only explained the consistency better (thick toothpaste), but also explained how to add water a spoonful at a time. It was really helpful all around. Especially when I started adding water and the grout became a tan color rather than the white I was expecting. Lauren explained in the video that grout dries lighter. 

So, with that preparation, I began mixing my grout to a thick toothpaste consistency. Then I donned my nitrile gloves and started smearing the grout into the cracks. For the outside edges, I used one finger running along the tops of the tiles and another running along the side to create a smooth wall (fourth image above). When I filled all the spaces between the tiles, I waited 10 minutes as the instructions on the package indicated.

Then I took a damp sponge and started wiping away the grout from on top of the tiles. This was actually a lot easier than I thought it would be. The grout wiped off smoothly except for the areas where my tiles had dimples and dents. However, I was able to just fold the sponge to a point to clean out those areas. You could probably also use a wet paintbrush or Q-tip. I had to rinse the sponge a few times during this process to keep from re-smearing grout all over again. 

When I had cleaned off the tiles to my satisfaction, I wet a small paintbrush and wiped it into some areas of grout that weren't quite smooth. Then I used my finger to smooth that out again. 

One final swipe with the sponge, and I was happy with the result. Now I just needed to patiently wait for it to dry.

The internet says grout is solid after a few hours, but needs 1-3 days to fully cure before messing with it too much. However, you can still put it on display once the grout is dry. Since it dries much lighter, you should be able to tell from the color.

You can add hanging wire which I explain at the bottom of this Instructable to hang it on the wall or use a stand like I did. However, you cannot put it outside because the air-dry clay can't handle weather.

And there you have it! A faux green leaf mosaic from air-dry clay. This was definitely a fun learning experience, and I will likely try something like this again. I hope you will try it out too!

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