I wanted to investigate in how concrete would act when being restrained by a flexible material (a balloon). By adding several balloons together inside a rigid form, they would also take shape by each other and the external shape. Like a specific brick-system, where they only can be placed in one specific way but then be perfect.
In the first stage i investigated how to cast into balloons and how the result would be. By using a funnel and making a more liquid mix (I used the mix of the flexible formwork but added water), the concrete easily flew into the balloons. By adding an extra tension to the shapes, with the string, the shapes became more interesting!
Before casting into the balloons, the rubber had to be stretched out, to maximise the amount that fits into them. So I simply blew them up for a few minutes before casting. I then started to fill the external wooden frame with the concrete filled ballons. To some I added rubberbands, to others I did nothing, and a few of the balloons where also heart-shaped which by themselves created interesting shapes!
When the box was filled and dried, this was how they look, the tob being more 3dimentional and the bottom more restricted:
And when stripping them of the ballons and then returning them to the shape, this is how they looked (because a lot of water was added, it created a layer on top where only water and a little bit of sand and concrete gathered, and cracked):