Fracture — a Brutalist Concrete Sculptural Lamp

Hi, my name is Arush, an engineering student with a deep appreciation for design, making, and the process of turning ideas into tangible objects. I especially enjoy experimenting with different materials and finding unconventional ways to build the things I imagine.

I came across a sculptural lamp design a while ago that immediately caught my attention. Its brutalist geometric fragments, sharp edges, and unusual arrangement around the light source made it feel more like a piece of sculpture than a conventional lamp. I wanted to explore that idea and create my own interpretation using cement and concrete.

For this project, I also wanted to make use of materials that were already lying around at home. I used leftover cement from construction/renovation work, old cardboard boxes to create the molds, and the LED assembly from an old planet night lamp as the light source. Instead of buying new materials wherever possible, I wanted to see how far I could go with things that already had a previous purpose.

Here’s the result: a decorative concrete lamp made from individually cast fragments arranged around a salvaged light source. The project combines 3D modelling, cardboard mold-making, cement casting, and a little bit of improvisation to turn leftover materials and an unused object into something completely new.

Here are the materials and tools I used to make the lamp:

Software

1. Blender — for modelling the lamp fragments
2. Fusion 360 — for modelling the base
3. Pepakura Designer — for creating the cardboard mold templates

Materials

1. Cement
2. Water
3. Cardboard sheets
4. Cello tape
5. Super glue
6. Cement powder
7. Fiberglass rod
8. Foam pieces/feet
9. Spray paint
10. LED board and wiring — salvaged from a planet night lamp
11. Sand

Tools

1. Printer — for printing the mold templates
2. Scissors and craft knife
3. Sandpaper
4. Soldering iron
5. Pliers
6. Measuring tools

Each project starts with inspiration and a concept.

I stumbled upon this lamp design a while ago and wanted to make something similar. What caught my eye was the brutalist design, with geometric fragments and sharp edges suspended around the light source, giving the whole piece the appearance of an otherworldly monolith.

I especially liked the contrast between the heavy, solid-looking concrete forms and the light glowing from within them. The unusual geometry made it feel more like a sculpture than a conventional lamp.

I wanted to take this idea as inspiration and create my own version using cement and concrete, while changing the form and construction to suit the materials and tools I had available.

Now that I had the inspiration and a rough idea of the form, it was time to start modelling the individual fragments.

I used Blender to create the fragments. Like almost every Blender project, I started with the humble default cube.

I first shrank and stretched the top of the cube to give it the basic shape I was looking for. I then applied different-sized bevels to each of the bottom corners. This made each fragment slightly different instead of having every piece look perfectly identical.

Once I was happy with the basic shape, I used Blender's Knife Tool to cut and split the main shape into five individual fragments. This gave me the angular, broken-up appearance I wanted.

The fragments needed some thickness to make them suitable for casting. To achieve this, I duplicated each fragment and scaled the duplicate down to create the inner faces. I then connected the inner and outer surfaces to form the walls of each fragment.

Finally, I added a few additional bevels and manually tweaked some of the edges to remove overly sharp or awkward transitions and give each piece a more natural, sculptural shape.

To create the base, I switched to Fusion 360 so I could make a more precise model that could later be 3D printed.

First, I imported the fragments into Fusion 360 and resized them to fit the overall design. I then sketched the circular base with a diameter of 165 mm and extruded it to create the second level, which had a diameter of 135 mm.

Next, I created a cavity in the centre of the base to accommodate the lamp and added an exit hole for the wires.

Instead of keeping the entire base solid, I decided to hollow out the bottom section. To maintain its structural integrity while reducing the amount of filament required for 3D printing, I added supporting ribs inside the hollow section.

Finally, I modelled a separate bottom lid to close the hollow section after the electronics and wiring were installed. This also keeps the internal structure hidden while making the base easier to assemble and access when needed.

I decided to make the molds for the concrete fragments out of cardboard. Since the fragments had an irregular geometry, I needed a way to convert the 3D models into flat templates that could be printed, cut, and assembled.

To create the templates, I used Pepakura Designer. Before importing the models into Pepakura, I had to make a small change in Blender.

I opened each fragment in Edit Mode, selected all the faces, and used the Shift + N shortcut to recalculate the normals and flip the faces outward. I then exported the modified model as an STL file.

After importing the STL into Pepakura, I unfolded the 3D model into a flat pattern. Because of the size and geometry of the fragments, I used the Cut and Move tools to divide each fragment into 2–3 sections. This made the templates easier to print, cut, and assemble while keeping the overall shape accurate.

Once everything was unfolded and arranged properly, I exported the templates as a PDF, ready to be printed and used for making the cardboard molds.

After printing the templates, I cut out each piece and glued it onto old cardboard boxes I had saved at home. Once the templates were transferred, I carefully cut out all the individual sections.

To make the cardboard easier to fold along the marked lines, I made shallow cuts along each fold. I also numbered and marked the pieces so I could identify where each section needed to be joined during assembly.

Since the cardboard would be in direct contact with the cement, I wanted to prevent the mixture from soaking into or tearing the cardboard while also getting a smoother finish on the cast surface. I covered the inner faces of each piece with cello tape, creating a thin protective and relatively smooth layer.

Finally, I folded and glued all the pieces together to form the individual molds. I reinforced the joints and seams with additional cello tape to make sure the molds were strong enough to hold the cement without opening up or leaking.

Using old cardboard for the molds also meant I could reuse material that would otherwise have been thrown away, while still creating a precise mold for each fragment.

For the casting mixture, I used leftover cement from construction and renovation work at my house. Instead of letting the remaining cement go unused, I decided to give it a new purpose in this project.

I prepared a 2:1 mixture of cement and water, mixing it thoroughly until there were no visible clumps and the mixture had a smooth, uniform consistency.

I then carefully poured the cement mixture into each mold. After filling them, I gently tapped the molds from different sides to help release any trapped air bubbles and allow the mixture to settle into all the corners and details of the mold.

Since the cardboard molds were lightweight and could easily tip over, I placed them upright in a bed of sand. The sand supported the molds from all sides and kept them in position while the cement cured.

After letting the cement cure for two days, it was time to remove the molds. I carefully cut and peeled away the cardboard from each fragment. Thanks to the layer of cello tape on the inside of the molds, the cardboard came off without much trouble and left the fragments with a smooth surface.

Once all the molds were removed, I inspected each fragment and cleaned up any imperfections left from the casting process. I used sandpaper to sand down excess cement and flatten uneven faces, while also refining some of the edges.

This step took a little time, but it helped clean up the fragments and gave them a more finished look before assembly.

While the fragments were being handled, one of the smaller pieces unfortunately broke. Instead of making the fragment again, I decided to repair it.

First, I carefully placed the broken pieces back together and aligned them as closely as possible. I then filled the gaps along the crack with fine cement powder. After that, I applied a few drops of super glue over the cement powder.

The cement powder reacted with the super glue and hardened almost instantly, filling the crack and locking the broken pieces together. Once the repair had fully set, I lightly sanded the area to remove any excess material and smooth out the surface.

Finally, I placed all the finished fragments in water for further curing, allowing the cement to harden and gain additional strength before moving on to the assembly.

Unfortunately, I ran into some issues with my 3D printer, so I decided to change the plan and make the base out of cement as well. This meant I needed to create a cardboard mold for the base.

The original base model had several details that were designed specifically for 3D printing, so it was too complicated to directly turn into a practical cardboard template. To make a printable template, I simplified the model down to its basic form.

I opened the base model in Fusion 360 and recreated only the two main levels of the base, leaving out the internal details and other features that weren't necessary for the mold. I then exported this simplified model and imported it into Pepakura Designer.

In Pepakura, I unfolded the model into a flat pattern and arranged the pieces to make them easier to print, cut, and assemble. After making the necessary adjustments to the individual pieces, I exported the finished template as a PDF, ready to be printed and turned into the base mold.

I printed out the base template and, just like with the fragments, cut out each individual piece and glued the templates onto a sheet of cardboard.

I then covered the inner faces with cello tape to prevent the cement from sticking to the cardboard and to give the finished base a smoother surface.

Since the base mold was considerably larger than the fragment molds, I wanted to make sure it could handle the weight of the cement. I reinforced the joints and seams with additional pieces of cardboard, making the mold more rigid and reducing the chances of it bending or opening while being filled.

Once everything was reinforced and securely joined, the base mold was ready for casting.

Once the base mold was ready, it was time to cast it.

I once again used sand to support the mold and keep it stable while filling it. To create the central opening for the lamp, I placed a spray bottle in the centre of the mold. This would act as a temporary core and leave a cavity in the finished base.

This time, I prepared the cement mixture slightly thicker than the mixture I used for the fragments. I poured the mixture into the mold and gently tapped the sides to help remove trapped air bubbles and allow the cement to settle evenly into the corners.

Once the mold was completely filled, I left it undisturbed for two days to cure before removing the cardboard mold.

After letting the base cure for two days, it was finally time to remove the mold.

I started by carefully removing the spray can from the centre, which left behind the opening for the lamp. I then cut away the cardboard mold piece by piece and peeled it off the concrete base.

Once the mold was completely removed, I gave the base a light sanding to smooth out the rough edges and remove any excess cement. After a little cleanup, the base was ready for the next step — painting and finishing.

Before painting, I filled in some of the minor cracks and air bubbles that were visible on the surface. Once the filler had dried, I sanded the base to smooth everything out and prepare the surface for painting.

I then applied the first coat of spray paint and let it dry completely. After that, I applied two more coats to get an even and consistent finish.

With the paint fully dry, the base was finally ready for assembly.

For the lamp, I decided to reuse the LED assembly from an old planet night lamp instead of buying a new light source. The original lamp was no longer being used, but the LED board and wiring were still functional, so I wanted to give them a new purpose in this project.

I started by removing the screws from the night lamp and carefully opening it up. I then unsoldered the wire connectors from the LED board and removed the LED assembly along with its wiring.

After extracting the LED board and wires, I resoldered the wires back onto the board, making sure the connections were secure and properly positioned.

With the LED assembly ready, I now had the main light source for my new lamp without needing to buy a new one. A component from an old, unused lamp had found a second life in a completely different design.

To mount the LED board inside the base, I first cut a strip of cardboard, rolled it into a small cylinder, and inserted it into the central opening of the base. This created a simple platform for the LED board to sit on while keeping it positioned in the centre.

Since the wire needed to exit through the bottom of the base, I also added small foam feet underneath the base. These created enough clearance for the wire to pass underneath without being pinched or damaged.

With the LED positioned and the wiring routed through the bottom, the base was ready for the fragments to be attached.

With all the individual parts finished, it was finally time to put everything together.

I used the same super glue and cement powder technique from the earlier repair to attach the first four fragments to the concrete base. I carefully positioned each piece before securing it, making sure the overall arrangement matched the design.

For the final fragment, I wanted it to appear as if it were floating above the others. To achieve this, I glued a fiberglass rod to the top fragment and cut it to the required length. I then passed the rod through the cardboard platform inside the base and glued it in place, suspending the final fragment above the light source.

After everything had set, I cleaned up the excess cement powder and made a few final adjustments to the fragments and their alignment.

And with that, the lamp was finally complete!

This project turned out pretty well. I had a few problems along the way, but in the end, I was able to create the decorative lamp I had imagined while giving several old and leftover materials a new purpose.

The cement left over from construction work at my house became the main material for the lamp, while old cardboard boxes were turned into molds for casting the concrete fragments and base. I also reused the LED assembly from an old planet night lamp, giving a working component from an unused object a completely new life.

What started as leftover materials and an old lamp eventually became a completely new piece with the brutalist and sculptural appearance I was aiming for. For me, that is what made this project especially interesting — rather than starting with new materials, I started with what I already had and figured out how to turn it into something useful and decorative.

Thank you for reading my Instructable! I really appreciate you taking the time to follow along with my project.

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