For my concrete vessel, I was inspired to create a succulent planter like ones that I had seen online. Instead of creating a simple bowl, I wanted to utilize concrete's rigid structure to make a form that was more geometric and interesting. I also wanted to work with wood in the shop more, so I took this as an opportunity to make my form from wood rather than cardboard wrapped in packaging tape.
I cut out a bunch of triangles using a Miter saw and scrap wood in the shop. I only needed 10 to make the form for my bowl, so with the spare triangles, I practiced and experimented with taping them together to hold their form while I glued the pieces together. While I did not end up using this shape in my final piece, I thought it looked interesting. The flexibility of the triangles taped together allowed me to create a lot of cool shapes, and it was fun just messing around with the ring of wooden triangles before I glued them all together.
To create the bowl shape, I also cut out a smaller pentagonal block to fit inside the larger form. This was suspended above the form with a beam, so concrete could flow underneath it. In the process of creating this pentagonal insert, I discovered that my form wasn't exactly pentagonal, but it was close enough that it still resembled the shape I was going for.
My first time pouring concrete was definitely a learning experience. I specifically purchased Topping Mix so my concrete would have less large aggregate in it. I was hoping this would have the effect of creating smoother sides for my piece, but there were still enough air bubbles and medium-sized aggregates that the exterior surface had a lot of imperfections. One very cool side-effect of using wood for my form, was the wood grain partially imparted itself onto the concrete. This gives the concrete a very fine striation that can only be seen up close.
My biggest mistake was with the pentagonal insert in the center. Because I didn't finish the wood block with any oil, the water from my concrete mix seeped into the wood, causing it to expand. This led to my concrete block cracking at its weakest points. It also meant that the pentagonal block was solidly infused with the concrete, making it impossible to remove by hand.
Because there are a lot of imperfections with this geometric concrete bowl, I am not particularly attached to it, and I think a really fun way to get the pentagonal insert out would be to set it on fire! Once the concrete dries and cures fully, I'll douse the whole thing in gasoline, and burn it until the wood inside turns to ash. This should also give the concrete a cool burnt exterior finish.