Brutus - Diy Concrete Sculpture

It is summer again and I thought I would make a new concrete sculpture into my garden. I have long wanted to make something in brutalist style and this was a good opportunity to try it.

Some sketching and 3d modelling and may the work begin.

After some looking I found my "temporary" quickly assembled foam cutter that I made last year for my diy concrete aqueduct project and therefore could use it to cut the shapes I needed out of EPS board which is 100 mm thick. Cutting these shapes also required a pattern and so I made one out of wood fiber board. Each of the pieces will sit under a different angle in the mold and therefore is different in length but the overall shape is the same.

Some of the edges of the sculpture were designed to be under an angle and therefore I had to make some longer EPS pieces with a triangular cross section. This ended up not being such an easy thing to cut as it may seem but it is needed for the looks.

The mold for the Brutus is a simple rectangular box with 250x2200x100 mm inner dimensions. I used 100 mm wide boards to make the edges and some old melamine particle boards to make the base. The 3 boards inside the sculpture mold are there temporarily keeping the long side boards straight while I attach them to the base.

The mold for the base weight is also just a simple rectangular box with 500x500x100 mm inner dimensions.

I also cut a 100 mm long piece out of a pvc pipe (100 mm in diameter) to make a piece that is going between Brutus and the base weight. Then I cut a slot into its side and covered it with duct tape to make the later removing part a bit easier.

I used hot glue to glue all the EPS pieces into their correct place.

Also I had to solve the assembling of the 3 pieces of the sculpture. I drilled a 15 mm hole into the center of the Brutus mold lower end board and fixed an M14 threaded rod through that hole with nuts. The rusty piece of metal there is just a scrap washer that was a leftover from a previous project. Screwing two nuts together is enough.

Then I glued together the mold pipes for the small cylinder and then glued one more small plastic pipe into the center of the base weight mold. These small ones will later be removed partially.

Before the pouring part I had to bend some armature. I used thinner ones that I already had and inserted long and short ones into different places in different layers but looking back now I think it would make sense to add some thicker armature into the thinnest parts of the shape. Especially the lower end of the sculpture where the load is larger.

Then it was time to pour the concrete which is a straight forward process since one side of the mold is open but it is important to make sure that all tight corners are filled completely. That is why I don't recommend quick drying concrete for this kind of project.

A small piece of EPS in the base plate is there to form a space for the nut that will later hold everything together.

After 48 hours of waiting I removed the edges of the molds to open up some more surface area for the curing process and turned the newly formed shape onto its side. Then I waited for another 12 hours before continuing the work.

Opening the molds went smoothly. I used a chisel to remove the bottom piece of the mold that was holding the threaded rod in place.

Removing the EPS board is a messy job and I did it inside my garage because there is no wind there. Removing itself is simple since sides of the pieces are accessible. Then some cleaning with a wire brush and I also had to remove some excess concrete from the sharp edges with an angle grinder.

After the "fun" cleaning everything up process it was time to put the pieces together. This went smoothly but it is still a rather heavy sculpture and so moving it around takes some effort.

It all took more time than expected but ended up looking as expected. At the moment its place in the garden is not 100% certain but when the final place is decided I will dig the base weight into the ground. This probably makes it look a bit better.

Lets name it Brutus :)