Plan B

After not being successful with the beach balls I decided to make a ball out of polystyrene to use as a form for my BB-8 body. I had a few sheets of 50mm thick polystyrene that I decided to use. I started by calculating what the angle should be as well as the disc diameter of each disc so that I could cut the polystyrene.

I needed to cut 12 discs from the polystyrene sheets. After marking the disc sizes I rough cut the polystyrene sheets with a box cutter.

I then set my polystyrene cutter up to cut the different diameters and angles.

After a lot of cutting I stuck all of the discs together in the correct order and left everything to dry. After the glue was dry I used sandpaper (by hand) to smooth the shape to get a ball. This is what the ball looked like after sanding.

I did make up two sanding blocks with the correct curvature to make getting my ball round easier. I used corrugated cardboard, hot glue and sandpaper to make the sanding blocks. They did the job well and the cardboard held up well under the stress of the sanding.