If you follow my projects, you know that this sphere300 adopts the same technique of Modular PCB Origami to connect each module.

When I start to build this sphere, I realize that there are some difference between these two projects.

For FR4 board, each is a triangle. You could use almost any PCB holder or hot plate to do soldering. For flexible PCB, it is different. I am using solder paste plus a hot gun for soldering. The problem with clips is that they would leave its teeth-print on the flexible PCB. In the end, I use a magnetic PCB holder.

For assembly, it becomes challenging. In particular at the end, the space is tight. Your solder iron should be poked in very carefully to connect two modules.