Concrete Stepping Stones Pt. 2--Live, Learn, and Grow

Although the Kindergardeners did an excellent job on the stepping stones, I personally needed to learn from a few errors I made along the way.

First, most of the stepping stones split broke or even completely crumbled when they dried.  The reason being is, of course, my husband and I didn't poor the concrete thick enough--the circular plastic plant container trays we had used as molds had these ridges on the inside-bottom (to ensure a container would be slightly raised to allow water to drain in, I suppose).  The stones cracked right along these ridges like pieces of a pie.

Second, I had purchased the cheapest, lowest grade concrete mix out there.  I was warned about all the pebbles and debris in this kind of mix, but thought, hey, it would just make the stepping stones more "rustic" in appearance.  Unfortunately, it also meant there was more rock and rubble instead of concrete, and this made it difficult for the concrete to set into a solid mass.   All the pebbles also made it challenging for the children to write in the stones, or to make leaf impressions.

Third, I ignored the on-line suggestion to add a thin screen or wire mesh when pouring the concrete into the molds (about half-way deep), to help provide internal structural support.

Finally, I heeded the on-line suggestion to wait 10-20 minutes for the concrete to set enough for the kids to write in it with a stick (which didn't really work anyway, because of all the rocks).  However, I found the concrete dried so fast, that by the time the last group  of kids came out it was hard for them to press the marbles, shells, etc. I supplied into the stepping stones.

I had taken the stepping stones to cure at my place.  When they broke, I decided to try and repair them as best I could.  I sifted the pebbles out of the remainder of the mix I had left, and made a smoother, more workable concrete.  I poured the mix into the molds, added a bit of screen this time, poured in a bit more mix, then placed the pieces of the Kindergardeners' stepping stones on top, matching up the pieces as best I could.

It worked!  When I checked up on the stones a week after I put them in the school garden, only one had crumbled, and 4 remained solid.  They don't look quite as nice as when the children first did them, but hey, live, learn and grow, right?