It's about time to try a new DIY project using a glorious old Italian technique: terrazzo-ing. Is that an official word yet? I think what makes terrazzo so appealing – aside from making great use of remnant materials – is its convertibility and variety. You can customize it numerous ways, from color choices to the scale of the pieces, to the materials you use, which is a dream for creative types. Before I begin, I might add that while this particular clock turned out great, it was not without trial – and errors. So learn from my mistakes, and let's get ticking.
What You'll Need
10-12 sturdy cardboard box, or silicon mold*
Plaster of Paris
Stirring stick or spoon
Mosaic glass, sea glass or similar
Gold movement/clock kit - this one is white, but I painted it gold
Acrylic paint color(s) of your choice
Gold leafing paint (optional)
2 wood blocks
Painters tape (optional)
1/4-inch masonry drill bit
Bandana or dust mask
*I used a sturdy gift box as my mold, which worked fine aside from creating an extra step to strip some of the paper coating off of my clock face before sanding. When in doubt, silicon molds tend to work best for plaster projects, so feel free to try out a silicon cake mold instead.
**Power sanders are great, but they're pricey, so if you don't already have one, you can just as easily use a sanding block and a little elbow grease.
Step 1. Arrange your assorted glass pieces in the bottom of the mold. Make sure the side you want to show is face-down against the mold, and leave space around the center where your clock kit will be added. And keep in mind that the pieces may move slightly when the plaster is added, so it doesn't need to be perfect.
Step 2. Mix your plaster according to the instructions provided, aiming for a pancake-like batter. Once it's smooth, you can add small amounts of acrylic paint to tint your plaster before pouring it into your mold.
Step 3. Slowly pour the plaster into your mold, trying to minimize moving the glass pieces; if you pour too quickly they will shift as the plaster settles in. The plaster should only be about 1/3-1/2 an inch thick so that the clock kit screw can fit through the clock face. Carefully tap the mold on a flat surface to help remove air bubbles and to fully fill in the areas between the glass pieces. Set aside on a level surface until the plaster goes from warm to cold to the touch (about an hour).
Step 4. When the plaster feels cold to the touch, slowly peel back the mold. If you're using a cardboard box, there may be remnants left on the clock face due to trapped moisture (lesson learned). Remove larger pieces by hand, the rest can be removed by the sander.
Step 5. Using a bandana or dust mask (protective eyewear is recommended as well), gently sand the sides, front and back of the clock face. The goal is to remove any uneven edges, level the face, and to make sure all of the glass is exposed. You can wipe with a cloth to remove any additional dust.
Step 6. (Optional) Tape off the sides of your clock, leaving only the edges exposed. Paint each edge using the gold leafing paint to add a more final touch to the clock face.
Step 7. Find the center of your clock face using a ruler or straight edge. Set your clock face up on the blocks to elevate so the drill can pass through, and slowly drill a clean hole through the center in preparation for the clock kit.
Step 8. Before applying the clock kit, determine which side you would like to mark 12 o'clock. Flip the clock over to the back. Using the same drill bit, drill a hole only halfway through the back of the clock. You will be able to use this indention to hang your clock off of a simple screw or nail. Note: It's important to remember that the clock battery pack will sit 1/4-1/2 an inch off the back of your clock, so plan to use a longer screw or nail when hanging to make sure the clock hangs flat, with the battery pack flush against the wall.
Step 9. Following the clock kit instructions, screw in your battery pack and attach the hands. If the screw feels too snug, drill the hole slightly larger until it sits comfortably, but not too loosely, in the hole. You can secure the battery pack to the back of the clock with super glue if movement is an issue. You can also trim the hands with scissors if they extend past your clock face.
Step 10. Pop in a AA battery, place on a screw or nail, set the time. It's most satisfying to watch the second-hand tick away after all your hard work.