Parametric Coral Tubes, Concrete Wall Sculpture

Final. Framed and mounted above fireplace.
Closeup. This piece looks most interesting from sharp angles.
Underneath.

Build process: Modeling.

Modeled 3 different tube shapes using Grasshopper in Rhino3D.
This will be a wall hanging, so this is the head-on rendering.
An angle view.
Another angle view.

Build process: Silicone molds.

Positives printed on Formlabs SLA printer.
For each part, I 3d printed a casting sleeve and interior structural support.
Hot glue was used to seal the sleeve seam and attach the sleeve to a smooth surface — hot glue seals well and is easy to remove. The sleeve and model positive were coated lightly with Vaseline.
Since the models have some deep undercuts, I cast with a high grade silicone resin (Tap Plastics Platinum Silicone Resin). This is a soft and tear-resistant resin.

Build process: Concrete.

I reused the sleeves and insert to improve stability when casting concrete.
I used Buddy Rhodes counter top grade concrete mix with a generous amount of Owens Corning reinforcement fibers. I typically mixed concrete for 6 molds at one time, making the mixture wet enough to flow. After fully mixed, I moved the mixture to a large plastic Ziploc bag, cut one corner, and piped into molds.

Build process: Mounting and framing.

After pouring about 60 parts, I stained a 24″ x 24″ plywood board. I marked the layout grid with chalk, and attached each part with epoxy.
I made a roughly 5′ x 5′ “frame out of 5.5” walnut boards, using dowel joinery.
You can never have enough clamps.
Photo of back of joined main piece and frame. They are attached with 20 dowels (photo is from a test, some only a couple of dowels are inserted).

A Cheap Vibration Table for Concrete Tiles

Here’s a simple vibration table for making concrete tiles, made with a Black and Decker Mouse, some screws, nuts, washers, and compression springs, and scrap wood.

The springs I used are 1 3/4″, 1/2″ OD, .054WG, but any reasonable gauge should work. Tighten the screws to create a little compression. Use a pair of nuts on each screw to keep the nut from backing off under vibration.

I mix concrete to a “wet sand” texture and trowel into molds. The table helps create an even distribution with no voids and levels out the open surface of the mold.