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Concrete Sculpture
Forest C. Greenslade, PhD
Creator of Forrest Dwellers^SM
Nature inspired sculpture and paintings

Sculpting with concrete

Concrete seems like an unlikely material for small-scale artwork, but it is ideal. It is inexpensive, readily available, and when made correctly, is hard and durable, both indoors and out. A comprehensive outline can be found online at: http://www.makersgallery.com/concrete/index.html.

I find it to be a versatile and cost effective material for producing both decorative and functional art and craft objects. Whether you have extensive experience in sculpting with other materials such as clay, wood or metal, or are just starting your life as a sculptor, concrete can be an important part of your materials tool box.

What is concrete?

From Wikipedia: Concrete is a construction material composed of cement (commonly Portland cement) as well as other cementitious materials such as fly ash and slag cement, aggregate (generally a coarse aggregate such as gravel, limestone, or granite, plus a fine aggregate such as sand), water, and chemical admixtures. The word concrete comes from the Latin word "concretus", which means "hardened" or "hard".

Concrete solidifies and hardens after mixing with water and placement due to a chemical process known as hydration. The water reacts with the cement, which bonds the other components together, eventually creating a stone-like material. Concrete is used to make pavements, architectural structures, foundations, motorways/roads, bridges/overpasses, parking structures, brick/block walls and footings for gates, fences and poles.

Cement is made by heating limestone with small quantities of other materials (such as clay) to 1450°C in a kiln. The resulting hard substance, called ‘clinker’, is then ground with a small amount of gypsum into a powder to make ‘Ordinary Portland Cement’, the most commonly used type of cement (often referred to as OPC).

Portland cement is a basic ingredient of concrete, mortar and most non-speciality grout. The most common use for Portland cement is in the production of concrete. Concrete is a composite material consisting of aggregate (gravel and sand), cement, and water. As a construction material, concrete can be cast in almost any shape desired, and once hardened, can become a structural (load bearing) element. Portland cement may be gray or white.

My concrete mixture

The concrete mixture that I use for sculpture is equal amounts of Portland Type I Cement and screened peat moss, moistened with water and a little Quikcrete Acrylic Fortifier.

What you need to get started

The best thing about concrete sculpture is that you can get started in an art or craft with little or no investment. You don’t need expensive equipment or a special studio space to make interesting and useful art or craft pieces.

Eguipment:
Three 1 to 2 gal plastic buckets
Inexpensive hand held gardening trowel
Chicken wire
Hardware cloth
Garden watering can
Plastic or rubber cloves (I use surgical gloves, because they give me better touch.)
Dust mask.
You will also need a variety of common tools: hammer, wire cutter, pliers, etc.

Supplies:
Portland Type I Cement
Garden Peat moss
Quikcrete Acrylic Fortifier
Quikcrete Concrete Sealer

Procedure

Mixing the Concrete:
1 - Using a piece of hardware cloth as a sieve, screen several trowel scoops of peat moss into one plastic bucket.

2 – Place 10 scoops of screened peat moss into the second bucket.

3 – Place 10 scoops of cement in the third bucket.

4 – Use the “house painter’s” technique of pouring the contents of each bucket back and forth to complete mix the cement and peat moss together. This will take at least five pourings.

5 – Slowly add a little water, and stir with the trowel until the mixture looks and feels like a clay that you might dig from a river bank.

6 – Add about three “glugs” of Quikcrete Acrylic Fortifier.

If the mixture is too wet, you can add more cement and peat moss. If it is too dry, you can add more water. As you work on your sculpture, you may have to add a little more water to maintain the optimal consistency.

Armatures

You can sculpt with concrete using either a mold or an armature. For pouring into a mold, make the mixture wetter. I primarily use an armature to support the concrete component of the sculpture. In my experience, concrete binds best to some kind of metal. I like to use chicken wire as a vehicle to bind the concrete to other support objects.

There are all kinds of materials that work well as armature materials:
Wood
Plastic pipes
Metal pipes
Plastic bags
Styrofoam
Fabricated elements
Found objects

Almost any support will work. I love the combination of fabricated metal and concrete. With metal, you can make thin elements such as wings, blades of grass, and wisps of hair. With concrete, you can shape facial expressions, rounded contours, and organic shapes.

An example

Slick Willy is a penguin happily greeting family and friends at the front door at Barbara and Mike’s house in New Jersey. The first step in sculpting Willy was to make a shape using chicken wire. This can be facilitated by placing a plastic bag full of plastic bags inside the chicken wire.

The concrete mixture was then pressed into the wire armature. I had to add the concrete in two or three stages, because gravity tends to cause it to fall downward. I first laid the armature on its face, and applied the mixture to the back. After twenty four hours, I turned it over and covered the front.

After a day or so, I coated the sculpture with Quikcrete Concrete Sealer.

Handling the sculpture

After the ingredients are mixed, for about an hour you can model the concrete with your hands, fingers and tools such as those used for clay sculpture. After the work has cured for approximately five to eight hours, it can be carved and refined with cutting and smoothing tools. After about 24 hours, the sculpture can be safely moved without breaking. You still should be careful not to jar or drop the piece. The curing process takes about three weeks to complete.

Surface Treatments

Concrete is amenable to a large variety of surface modifications. When the surface is still soft, a number of materials such as glass, stones, sand, metal objects, iron filings, natural materials, etc can be pressed into the surface. When soft, the surface can be painted with artist’s acrylics or exterior house paints. The painted surface can then be carved with a sharp tool to expose the underlying concrete. After the surface has become hardened, various treatments can be applied. One of my favorite treatments is to apply a metal coating, then stain or tarnish it with a patina. See Appendix 1 for details.

About Forrest

Strange creatures inhabit the mind of Dr. Forrest Greenslade. His whimsical sculptures and paintings, which he calls Forrest Dwellers^SM, are derived from a life-long love of nature and mythology. Greenslade’s work is highly stylized, bounding on cartoonish. His paintings are sculptural, built up with inches of thick acrylics and modeling paste to the point that they nearly jump off the canvas. His sculptures are enhanced with innovative coatings and patinas producing color, texture and an illusion of movement.

“I want people to experience motion and emotion in my art,” Greenslade asserts, “so my faces are seldom symmetrical and my figures just can’t stand still.” Greenslade’s use of materials is eclectic. “Because of my scientific training, I tend to be experimental in my choice of media,” he explains. “I use metal, concrete, clay, acrylics, wood, found objects – whatever tells the best story.”

Greenslade’s work feels rather naïve, even childlike. Educated as a molecular biologist, he spent his working life as a scientist and organizational executive -- but in his dotage, he discovered his creative self. “After a lifetime of serious business, it’s nice to let the little boy out,” he smiles. “It’s more fun that any old guy deserves.”