Saturday, 6 August 2011

August 6, 2011

Translucent concrete

We recast our concrete relief, and achieved this pseudo-translucent concrete sculpture (displayed in Alison's studio, Jan 6, 2011):



It seemed easier to just mix a special translucent additive into the concrete, add water, and pour. Thus we ordered some Ilum online from a Mexican company. However this company no longer exists, so we just used commerical cement to cast the above.

Much later I bought some Rocalite from Cuernavaca, Mexico, and we are experimenting with this cement additive. Ultimately, however, making translucent concrete is not as easy as adding water to cake mix. However, as seen in the YouTube video below, there are lots of variations:



We found our labor intensive DIY procedure on Instructables. Therefore I bought 2.0 mm Eska plastic fiber optic cable from Circuit Specialists Inc., in Mesa, Arizona (thanks to QueLab for helping me identify the fiber optic cable that would work with this project.) Then Alison, Eric and I then spent a day (Aug 6) in Albuquerque sticking short fiber optic strands into the Styrofoam mold at her studio. Much later Counter Intelligence poured polymer concrete into the mold and cast the "translucent-like" relief

Three-foot Styrofoam molds, CNC milled at FabLabAbq, and a spool of fiber optic cable:


We decided to pour a test brick first. Alison dug into a Styrofoam square by hand, to simulate the mold:


Then we pierced that Styrofoam piece with plastic fiber optic cable and set it in a plastic box, filling the remainder with oil based clay:


(Note: We glued some strands to the Styrofoam with Golden GAC 100 acrylic medium, which reacted with the plastic fiber optic cable and made brown spots at the punctures. The fiber optic cable did not turn brown without the acyclic medium, nor did the Styrofoam turn brown when only the acrylic medium touched it.)
Joseph at Counter Intelligence poured polymer concrete into that plastic box, and thus cast a test brick:


We snipped the excess cable, and placed the test brick in front of a light source to see the effect:


Then we spray mounted a 3 foot photocopy (made at Reproductions in Tucson) of the image onto cardboard, and drew dots on the image with a Sharpie marker. Eric punched those dots with a sharp awl and perforated the cardboard, thus simulating the light holes that the fiber optic strands would make:


Some of the holes we rejected, and sealed them with tape and oil clay on the back:


Once we found a light dot pattern we liked, we drew red lines over those holes, and used this punctured photocopy to guide us:


We then "dressed" the mold with Vaseline, to keep the air in the Styrofoam from surfacing (when the liquid cement is vibrated) and leaving holes in the final casting. The Vaseline also serves as a mold release:

Alison bored into the Styrofoam first with a needle, smaller than the diameter of the fiber optic cable. Then she stuck the fiber optic strands in those holes -- without any adhesive -- so that they fit snugly into the mold (thank you Alison, for acupuncturing the whole mold. I do not have that kind of patience.):


The mold, after all the fiber optic strands were inserted:


Pin points of light radiate from both ends of this giant axe pict sculpture, on the UTEP campus, in front of the lights of Juarez. I wonder if the fiber optic light points in our sculpture will look like these pin points.


The relief sculpture soon after it was pulled out of the mold -- note the long fiber optic strands at the bottom, which have not been cut yet:


The finished sculpture exhibited at the Tucson Sculpture Festival 2012 (Jan 27):


One of the breasts was blinking during the opening. I pressed a small strobe light to the back of the concrete relief, to show off part of the "translucency":


I experimented with AutoDesk's free 123D Catch software to make a 3D scene of my piece at the Tucson Sculpture Festival:



Heatsync Lab in Mesa, Arizona, allowed me to display the relief in their front window for the month of March (March 1):




Someone at QueLab polished the ends of some 1/8 inch acrylic rods with 600 mil sandpaper to demonstrate how nicely they transmitted light. Acrylic rod is a lot cheaper than fiber optic cable, for those of us still experimenting with translucent concrete.

After Googling, I discovered a different concept by Daniel Franke and Markus Kison -- one using camera projections to create the illusion of translucent concrete.

Finally someone pointed out how backlit countertops are related to the translucent concrete sculptures we are trying to create.

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