Workshop = Playshop
I was lucky enough to be able to spend four information and action packed days with an amazing Artist from the Czech Republic this past week. The topic was concrete sculpture. Note: my mom worked for the mothership of all such materials (The Portland Cement Association) in the 1970’s where I learned the difference between cement and concrete. Cement is the specialized powder part of the aggregate material. Concrete is what you have when you mix your cement with sand, gravel or other aggregates including the water and/or latex binders, etc.
Katerina Pinosova (www.katerinapinosova.com) has studied this medium intensively and has opened herself up to building on her deep knowledge through her own hands on explorations. Her own work is structurally sound from the inside out and she enthusiastically explains each step an artist must take to duplicate her successes with our own pieces.
I probably was exposed to as much information in our four days together as would be typical of a semester long class! I hope to retain everything Katka taught me because everything she shared was designed to help me understand working with cement from a fundamental level.
Mud is Tricky!
If you’re using it in any way besides pouring into slabs or moulds this is a very tricky medium indeed. The potential for error is great and the demands due to the timing of the drying are relentless. These can be affected by the humidity of the ambient atmosphere as well as the moisture levels already present in the material components of the cement powder itself and sand you mix with it.
Cement is heavy and requires a sturdy armature. It is also alarmingly prone to cracking so great care must be taken to apply it systematically and at the right moisture levels. For example, if you should mix up a bit too much, as you’re applying the first few trowels full your last will be drier or even suddenly unusable. You have to develop a feel and an eye for how your mix looks when it’s at its optimal application. As it deteriorates you must compensate with your own movements to alleviate the chances for it to fail as it dries in place.
I could go on and on. Suffice it to say for my purpose here that there are some good books written on this topic that come highly recommended. This one by Sherry Hill is one Katka particularly likes:
Rough 4 Day Schedule:
The following in no way is meant to serve as a complete How-To guide but should give the novice an idea of what to expect from a thorough process when starting your own project. Definitely read up and take a hands-on class if you can. Doing so did me a world of good!
- Choose or draw a Sketch that will work within the constraints of your expertise and available time
- Form your Armature using:
Filler for 3-D areas – styrofoam, cardboard, etc.
- Reinforce more than you think you have to
- Make every element secure and immovable
- Minimize wires sticking out
- Double up layers staggering or weaving the lines to maximize the overall strength
- Screen the sand (to remove pebbles and undesirable larger aggregate)
- Mix 2:1 – sand to cement
- Mix and apply SMALL BATCHES – PRESS cement onto and into your armature
- Apply first layer of cement
- Use Enough water to form a non-crumbly, pliable dough with a consistency somewhere between brownie and cookie dough.
- Wet and then….
- Thoroughly cover in plastic
- Hand mix the concrete to get a ‘feel’ for the correct consistency
- Hand mix the cement + water slurry to serve as your ‘glue’
- Work from the top down, outside in
- Press the cement into the layers
- Do not overwork
The more you mess with the cement, the crumblier or weaker it gets.
- Try to coordinate the timing of the amounts of cement you mix to what you can use while it’s still as close to optimal as possible. Don’t call in the cement truck unless you’re pouring yourself a swimming pool or some sidewalks!
The middle layer
- glue with concrete and water slurry
- Cement with fiber
- start suggesting your relief aspects
The final ‘fat’ and the details
- Apply your final layer of concrete using a slurry
- Anticipate and build out dimensional areas
- Go back and work on top of those to do the final built
- Fine tune carefully using metal tools when possible to minimize crumbling
The photos below take you through the four 8 hour days (32 hours) it took me to make my bear planter.
It is about 24″ x 16″ x 28″ and weighs about 130 pounds.
I feel I am now equipped with the knowledge necessary to appreciate the amount of work I need to be prepared to do to make more planters and sculptures. Below is my current shopping list.
The raw materials cost about $40 total.
Partial Shopping List
- Small pointed trowel
- Spatula shaped trowel
- 5 gallon buckets
- Hand cement mixer I ended up ordering this mixer.
- Mud paddle
- Empty yogurt containers
- Hardware cloth-stucco lathe
- Chicken wire
- Tie wire
- Needle nose pliers
- Small gauge rebar
- Bolt cutters
- Metal spoon
- Metal knife (Cement sticks less to metal tools)