Last year we visited Marseille and whilst there we went to Le Mucem which is a facinating building designed by Rudy Ricciotti

It's hard to describe, but several sides and some of the roof have these cast concrete decorative panels held away from the internal glass structure. That casts really interesting patterns of shadow and light. The overall effect is quite beautiful.

I decided to make a monitor stand inspired by this design. See the video for the full build process

The tricky part of this is scaling down the concept of the cast concrete panels to something small enough to deliver a similar effect whilst being strong enough to support a monitor.

The key ingredient here is something called Jesmonite

This stuff comes as a powder and a liquid which are mixed together to make something somewhat like a concrete/stone.

Tools required:

CNC / scroll saw / drill + files (you could make the master in various ways)

Welder

Grinder

Metal cutting saw (I used an evolution rage chop saw)

Materials:

Silicone mould making

Jesmonite

Angle iron

flat bar stock

Step 1: Create a Panel Design

The design has 3 important characteristics.

All the lines are fairly constant thickness.

They terminate at specific, symetrical end points along each edge.

Each panel is twice as high as they are wide.

So start by defining the end points along each edge. For mine I made the left and right side identical to each other and symmetrical around the mid-point. Then the same again for the top and bottom. Note that if you want to be able to tile the corner of a cube you would need the top/bottom edges to also have the same pattern as one half of the long edge.

Once you've defined the end points that fulfill the requirements for the size of tile and symetrical nature then save it at this point.

You can now create one of more tiles from this template. Just scribble lines that join up all the end points in whatever pattern feels right. In a program like inkscape you can use the freehand drawing tool.

The great thing about inkscape is that you can then 'simplify' these lines to smooth out any glitches in your hand drawn strokes into nice smooth curves. You can also just define your lines to be a given constant thickness to achieve the look. Note - if the lines are NOT pretty consistent in thickness it very quickly just looks wrong.

Once you have some tile files you like proceed to making a 'master' copy

Step 2: Making the Master

First you have to create the master copy for each of your designs.

There are a few ways you could do this. I have a CNC machine, so I put my sketch into Fusion360, extruded it to become a 3d body then created the necessary tool paths to carve the pattern out of a model making high density board.

However, you could equally print out your design, stick it to your material and cut/carve it with whatever you have. So a scroll saw would allow cutting out the small holes, though it would be quite time consuming to do them all. You could probably hand wield something like a dremel to cut out most of the holes. or even just carve them out with chisels.

It doesn't matter so much if you replicate your design exactly, just that the end points are all accurately cut, and that the pattern maintains the rules.

As always when casting parts, it is worth the time to make sure your master copies are good. Any flaws will be repeated.

Step 3: Create a Silicone Mould

For my design the panels are about 19cm by 9.5cm, so the holes are quite small. So the main thing when casting is making sure you don't trap air at the bottom of those smaller holes.

The other thing to consider at this stage is how thick the base is and how flat you get it. It's going to be important that when you cast these panels you want them to come out flat. So a slightly thicker base on your mould can help with stability of that.Obviously you want as much as possible to cast on a flat even surface so that the silicone settles flat relative to your master.

Step 4: Cast Some Panels

This is where the wonderful world of Jesmonite comes in. For scale the 'lines' in my tile are 5mm cross section which is not a lot of material. Cast Jesmonite once it is cured is still pretty strong at this small scale.

I tested this by placing one of my panels on supports at each end so the main span was in the air. Then put a concrete filled coke can on the middle. It was able to support this for about 10 minutes before it snapped. I figured that was a pretty good result for the worst case load. My design for the monitor stand was much like the mucem itself with metal supports along the long edges. I wouldn't expect to put any tile under anything like that much load.

Jesmonite comes as a white powder and a fluid to mix. its 2.5:1 powder to fluid. You can also buy dye's for Jesmonite. Be default it is a sort of off-white stony colour. I decided to dye all my panels black.

I ultimately created 2 designs, and cast 7 panels in total, 3 of one and 4 of the other.

Each panel is normally ready to de-mould in an hour or so. but it reaches it's fully cured hardness over 24 hours or so.

Note - impatience here caused me to break several attempts when trying to de-mould too early.

Reminder- you must make sure the mould is sitting on a nice flat even surface to ensure the tiles come out flat and consistent. Even a small piece of debris under one end can cause an annoying bend in a corner (ask me how I know :-)

Step 5: Create the Stand Structure

With some cast panels in hand you can use them to reference the spacing you need on the support structure. You could obviously just measure, but I like to have the final item in hand to avoid surprises.

My substructure design is a 'backbone' of angle iron, leading down into some feet at either side. With 'T' beams welded out of the backbone at intervals of the same width of the tiles. So 5 lengths of angle iron, a backbone, two risers (these are the same length as a tile is wide) and two 'feet' all cut with 45degree angles for the corners.

To make the mini T-beams I cut some flat bar stock in half length ways. This was tricky to do. I made up a little jig to hold everything in place on my chop saw (which is rated to cut metal) this would have been much easier with a metal cutting bandsaw. You could potentially do this with a thin angle grinder cutoff disk.

Once I had two bits I welded them with spot welds at evenly spaced down the length. I made 4 of these all the same length as the long edge of a tile. Even at this scale this simple T structure creates a log of strength.

I then used an angle grinder to cut into the 'backbone' angle iron little slots for the T beams at the correct intervals. Again, helpful here to have a cast panel to double check the spacing.

With slots cut, I welded the t-beams in place, and then ground the surface flat.

You need to be fairly careful not to warp the backbone piece in this process, since the welding is going to want to pull the slots in.

This metal frame is what is really taking all the weight. The panels are really just providing a decorative surface.

The structure is measured so that one panel will fit on each side, with 5 panels making up the upper surface.

Once everything was welded in place, I sprayed with black metal paint. An alternate could be to make the frame a contrasting colour to the tiles.

Step 6: Epoxy the Tiles in Place

I though about various ways to put the panels in place. Ultimately decided to just epoxy them in place. I just need them to be fixed in place. The glue is not taking any load, it's just holding thing in relative position on the frame.

The filldy part here was getting epoxy on all the little end blocks where the tiles both rest on the support struts and contact the tile next to them. I used some lengths of metal box section just to add a light clamping pressure whilst the epoxy cured.

The design of the tiles is such that you can place each tile in a different orientation, flipped either way around so that there are less obvious repeating patterns. Even a single tile design can look ok next to each other, but with two designs each flipped in different orientations you can achieve quite a lot of variation.

Step 7: Finish

I ended up putting small oak 'skids' on the bottom of the metal feet so that it would not mark my wooden desk.

It easily takes the weight of a monitor and I am very happy with how it look on my desk. The same light and shadow really does remind me of the mucem.