Art Concrete: How-to Guidelines + Use

THIS SERIES OF PAGES offers some detailed guidelines and recipes from my own experiments and research into using portland cement concrete for small scale art projects (jewellery, sculpture) along with ideas contributed by other artists. The series covers everything from materials and techniques to sources and hazards.

OTHER PAGES in this web site deal with more general technical questions, and you may want to start there. There is also a basic FAQ page, and an extensive list of art concrete links.

Also, here's a two-page PDF file of some workshop notes.

BRIEFLY...
Uncured concrete is difficult to handle directly. It usually needs some kind of form or structure to control the shape. This leads to three completely different fabrication methods:

• casting into a form -- and later removing the form
• applying to an armature -- expanded mesh, for example
• or carving a solid block -- which can be partially cured

• large: stone or gravel
• small: sand
• fine: stone dust (eg limestone or marble)
• extremely fine: silica fume, metakaolin

Concrete will get somewhat hard after 4 to 12 hours, depending on the mix and temperature, and can be worked with coarse files or carved at this stage. In one or two days it becomes harder still, but it is possible to wet sand to refine the shape. After that it becomes comparable to working with stone. It is best to add layers of new concrete within the first day or two after the initial set, when almost complete bonding takes place, but it is possible to add layers for several days.

A reader to this site sent me an Excel spreadsheet that simplifies volume calculation. You can download it here. Enter length, width and height in inches for a cubic volume, or height and radius for a cylindical volume in cubic inches or feet. [Thanks to Lynn Aavang.]

~Andrew Goss

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