by Juanita Canzoneri
One of my favorite ways to save money when making mosaics is to shop my garage first.
Over the years, I’ve used all kinds of unexpected materials as mosaic substrates, and wood is one of the easiest places to start. Leftover lumber, scraps from home improvement projects, and inexpensive sheets of MDF/hardboard can all become sturdy bases for mosaic artwork.
The trick is knowing what will work—and what is likely to cause problems later.
Start with What You Already Have
Before buying a special piece of mosaic board, check your garage, workshop, or scrap pile (or the scrap piles of friends and family). You may already have perfectly good material waiting to become a mosaic.
Leftover 2" x 4" lumber can be particularly useful for small, chunky pieces. I’ve also used 2" x 2" trim and other scraps of wood to create interesting bases.
Don't worry if the wood isn't perfectly square or straight. In fact, some of those imperfections can become part of the character of your finished piece.
Pay Attention to Thickness
The thickness of your wood matters for two reasons: weight and hanging hardware.
A thick piece of lumber can make a wonderful, substantial mosaic, but once you add glass or ceramic tile, grout, and adhesive, it can become surprisingly heavy. Think about how you plan to display the finished piece before you begin.
If you're making a wall-hanging mosaic, consider the weight of the completed artwork—not just the weight of the wood. I always overestimate the weight of a finished piece when buying and attaching picture wire and hanging hardware.
Seal the Wood First
Wood is porous, and moisture is not your friend when you're making a mosaic. Water-based adhesives and grout can introduce moisture into the substrate, so I recommend sealing the wood before you start.
A couple of options are gesso or a water-based wood primer such as Kilz primer. Apply the sealer to the surface and allow it to dry completely before beginning your mosaic. NOTE: always choose water-based primers over oil-based. Oil based primer + water-based adhesive = FAILURE.
Don't forget the edges. Sealing the edges and back with primer as well as the front gives you a more stable finished piece.
Think About Hanging Hardware before You Start
This is one of those things that's much easier to figure out before your mosaic is finished.
Depending on the size and thickness of your wood, you have several options.
D-rings
D-rings are a good choice for many wall-hanging mosaics. They can be attached to the back of the wood and used with wire or alone with appropriate wall hardware.
A drilled hole
For some thicker pieces of wood, you can simply drill a hole through the substrate near the top. This creates a surprisingly simple hanging solution and eliminates the need for additional hardware.
Picture-hanging hardware
Standard picture-hanging hardware can also work, particularly for smaller and lighter pieces.
Whatever method you choose, consider the finished weight of your mosaic. A piece that feels lightweight before you add tile may be considerably heavier when you're done.
Finishing Your Wooden Mosaic
Once your mosaic is complete and the grout has cured, you can give the wood a finished look that makes the entire piece feel intentional.
Start by making sure the wood is properly sealed. Then consider painting the edges and back with acrylic paint.
This is an opportunity to add a little personality to your piece. Black, white, or a color pulled from the mosaic can all work beautifully.
For a more finished and durable surface, you can apply a final coat of water-based polyurethane after everything else is completely dry and cured. This can help protect the exposed wood and painted areas from everyday wear and protect your wall from paint transferring from your wood edges.
Just be sure to follow the manufacturer's directions for drying and curing times.
A Few Caveats about Found Wood
Not every piece of scrap wood is a good candidate for a mosaic.
Choose wood that's in good condition
Avoid pieces with rot, major cracks, or significant damage. Remember that you're going to invest time and materials into your mosaic. It's not worth putting all that work onto an unstable substrate.
A few dents, scratches, nail holes, or other imperfections are usually no problem. Those can add character.
Avoid wood that's too thin
Very thin pieces of wood can flex, and movement is something you generally want to minimize in a mosaic substrate. I typically don’t go any thinner than ¼” for my substrates.
Don't fight the curves
Here's one of my favorite things about using found wood: you don't necessarily have to make it perfect.
If you've found a piece with an interesting curve or irregular edge, consider using it exactly as you found it.
Your mosaic doesn't have to be a rectangle.
Following the natural shape of a piece of wood can give your artwork a more organic and interesting appearance—and it's one less thing you have to cut!
What About MDF?
If you don't have suitable scrap lumber, MDF (medium-density fiberboard aka hardboard) is another inexpensive option.
MDF is available in sheets, commonly in thicknesses from about ¼" to ½", and it can be cut into virtually any shape with a jigsaw, CNC cutter, or bandsaw.
A ¼" thick, 2' x 4' sheet of MDF can be a relatively inexpensive way to create multiple mosaic substrates. You can find it in the same general area of a home improvement store where you would find pegboard and other sheet goods.
The biggest advantage is flexibility: buy one larger sheet, cut it into several substrates, and you can get quite a few mosaic bases from a single purchase.
The catch? You need a way to cut it.
If you don't have the necessary tools, ask a friend who does, or see whether your local home improvement store offers cutting services. (Most home improvement stores will give you 2 cuts for free.)
Once you've cut your MDF to the shape and size you want, seal the surfaces and edges before beginning your mosaic, just as you would with a piece of found lumber.
One Important Warning: Don't Substitute Plywood
It might be tempting to grab a piece of plywood because it's inexpensive and easy to find.
For this particular application, I don't recommend it.
Plywood still has wood grain running through its layers, and it can be prone to movement and warping when exposed to the moisture found in water-based adhesives and grout.
MDF, when properly sealed, gives you a much more stable and predictable surface for this type of mosaic work. Why? Because it’s a composite material there is no woodgrain as there is with plywood.
Look at Your Scrap Pile Differently
One of the best things about making Mosaics on a Shoestring is learning to see potential where you might otherwise see waste.
That leftover piece of lumber doesn't have to become another item in the scrap pile. An inexpensive sheet of MDF doesn't have to look like a construction material.
With a little preparation, either one can become the foundation for a beautiful piece of art.
So before you order a fancy mosaic substrate, take a look around.
What do you already have that could become your next mosaic?
You might be surprised.