Saturday, July 5, 2014
I went back to a tried and true process though...making "Hypertufa". I've made pots and planters from this material years ago, so I knew what to expect there. But the use of wooden branches for the supports to my bird bath falls into the "risky" category. But nothing ventured nothing gained!
You may have never heard of the term "hypertufa" before. It is a mixture of Portland Cement (the fine powder...no rocks in it...most hardware stores carry it), Vermiculite (a soil enhancer from the garden center) and Spagnum (or Peat Moss...also from most garden centers). When this concrete mixture dries, it has the look of old, weathered rock. And it is 2/3rds lighter than a solid concrete piece.
I had taken a couple of classes, and the recommended approach was to build up the shapes with the "golf balls" instead of just big sloppy handfuls of material. I sprayed it with PAM cooking spray first, to act as a release agent. I was applying the hypertufa mix to an upside-down plastic serving tray. Bit by bit, I covered the tray, so it looked like a giant cow pie. I let it dry for 24-48 hours...and viola! A bird bath bowl!
Next I roughed up the surface with a wire brush. To make the bowl more water-proof, I rubbed in a light layer of Portland Cement, misting it with water, until it blended and made a smooth surface. I didn't like the results, so I made up a very wet mix of cement to put on top. But I got it too wet. So...making lemonade from lemons...I just got a brush and made a swirl pattern in the bowl. I was working on a "lazy susan", and could turn it like a potter's wheel.
Now for the very bottom of the base...the "stump". I had to do a bit of research about sculpting in concrete. Most of the articles recommended using steel rebar for the inside of a concrete structure. I have never worked with it, and don't have the heavy duty tools for cutting and welding it. I am using steel wire mesh to make an under-structure that I would add to later. I added a bit of CEMENT with SAND mixture to the wiring, and let it dry for a day. Notice the pieces of PVC pipe...that is for the drain holes to my "planter".
Posted by Warren Ludwig
at 8:39 PM