Some supplies you'll need or just find handy:
- Portland cement type I
- Dish pan (dedicated) for mixing in
- Some sort of trowel or small hoe as a mixing tool
- Some sort of disposable, or never to be used again for food, cup for scooping sand and cement.
- Clean water for mixing (or admix of some type if you live in a frost zone- read labels at your home center to find an appropriate admix).
- Disposable dust mask. Very important to wear this while working with the dry cement!!
- Hardware cloth
- Wire cutters or similar for cutting hardware cloth
- Gloves- heavy duty for use when cutting hardware cloth and vinyl disposable for when mixing concrete.
- Mold. For this project I use a 14" diameter commercially made stepping stone form.
- Clear contact paper
- Some sort of tesserrae for piecing a mosaic design. I use stained glass frequently.
- Mold release of some sort. I use petroleum jelly- cheap and easy to find.
- Newspapers for work area
- Plastic to cover concrete after unmolding.
- Sturdy board larger than the mold to use when flipping the mold in step 6.
1. The mosaic design is pieced in reverse on the contact paper. Place the mold on the paper side and trace it then cut the shape out 1/4" inside the line so it will fit inside the mold. You can sketch out a design on the paper portion. Peel off paper, and place sticky side up on your work surface with the design underneath. Remember to reverse words/letters/numbers so they are mirror image while piecing.
2. Figure out how much sand and Portland cement you need. For this project I use recipe #3 in the book Making Concrete Garden Ornaments by Sherri Warner Hunter. One great tip, among many, from this book is to fill your mold with sand and measure the volume. This will be how much you use for the project and 1/3 of this volume is how much Portland cement you will need. Use approximately half as much water/admix as cement by volume. I have a wonderful old clear plastic pitcher with very straight sides that I have marked this ratio on for each mold size I use.
3. Smear a thin coating of petroleum jelly on the inside of the mold. Place the contact paper/pieced design into the bottom of the mold with the pieced design sticky side up. Use the wire cutters to cut a circle of hardware cloth about 2" less in diameter than your mold (one inch smaller each side).
4. Add the sand to your plastic bin. Put on your mask and measure out the Portland cement and add it to the sand. Stir in well and slowly add in water/admix in increments. Be real careful that you do not add too much liquid. I aim for a very soft cookie dough consistency. Not crumbly but never runny.
5. Go slowly adding the cement mix to your mold. You need to press the concrete into all your spaces but carefully so you do not dislodge your pieces from the contact paper. Fill the mold half way then place in the hardware cloth piece. Raise slightly and tap the mold down to the ground repeatedly to raise any air bubbles. Fill the mold the rest of the way and repeat the tapping to again remove air bubbles. Smooth the surface. Clean up plastic pan and tools OUTSIDE. Cement/concrete washed down a drain will harden in the drain!
6. The filled mold needs to sit undisturbed until the surface is firm and no indent is made when touched. I found the amount of time this takes depends very much on the air temperature. In the summer here (90's day 70's night) it required only six hours but in our current temps (70's day, 50's night) it takes 12 hours. When firm enough, gently pull mold away from sides very slightly. Place a stiff board (I use a leftover large floor tile) on the stepping stone surface and carefully flip the board and the mold. Slowly pull the mold straight up to remove. Remove the contact paper slowly. The surface can be gently cleaned using a paper towel or a piece of newspaper. Cover in plastic and leave undisturbed for at least three days. After seven days it will be cured enough for walking on and the color will lighten to about its final color.
Interested to see what else I've done with stepping stones? Click here to go to all posts tagged with 'stepping stone'. All designs are my own. If you make some stones I hope you use the opportunity to also create your own designs. Have fun!
I don't just play with concrete!! See my Etsy MosaicSmith shop for available mosaic art.