I'm just back from a few days in San Diego. The beauty and power of the ocean is hypnotizing. Living in Tennessee, it's such a treat to be able to whale watch, surfer watch, and crashing wave watch. One of those crashing waves jumped up way unexpectedly and drenched me head to toe. (My phone got to live in rice for 24 hours as a result...it has a couple of glitches which I'm hoping a factory reset will fix, but the rice thing definitely brought it back to life!)
A couple of weeks before my trip, I poured two small countertops on either side of the sink in the bathroom. With the leftover concrete, I cast two bowls. The bowls stay in the molds for 2-3 days, then they sit submerged in water for about a week. That process helps them cure more slowly. After that, I typically do any needed shaping, smoothing, or carving. In this case, I had taken them out of the water to dry but didn't do anything else with them before my trip.
Today, when I decided to clean them up and smooth out the edges, these bowls had been curing for almost 3 weeks. Concrete is 'workable' much longer than might be expected. It can be carved and sculpted almost like plaster early in its curing...the second to fourth day or so...but after that, it can still be altered for a few weeks.
I should say here that I am not talking about quick setting concrete...that would be an exception and not what I would recommend for casting anything that you want to be able to carve or sculpt. I will often mix my own concrete from Portland Cement and sand. It's very easy to do...I use 1 part cement to 3 parts sand, although more or less sand will work. By mixing my own, I can also vary the final texture by changing the type of sand I use.
Here's how it looks:
Before any finishing; sharp edges at the top...
And sand in the bottom that needs to be removed. I use a light spray of oil in the molds as a release agent. In this case, I threw some sand on the bottom to get a little surface texture, and I want to learn if the acid etch coloring (to be done later) will look different on the rough areas as opposed to the smooth.
These are my concrete clean up tools. The wire brush functions simply as a brush (obviously) to remove sand, but also works like a medium grit sandpaper. It will smooth edges and clean up all the surfaces. The chisel works like a scraper to remove more material at a time. It definitely cannot be a woodworking chisel anymore once you use it on concrete, so use an old one or an inexpensive one!
Done! Another week or so of curing and it will be ready to be colored.
I'll post when they're colored and sealed...the bigger bowl is asking for a plant I think...maybe a bonsai? I've been thinking about bonsai since seeing the bonsai garden at the North Carolina Arboretum in Asheville. So beautiful.
Hi, I'm Donna. Long time artisan/creative. Full time work in nonprofit world. Mother of two adult sons. Currently, also mother of two cats.
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