I cut the panels from two ply cardboard sheets using an Olfa knife. It is very important to use a really sharp edge - and I always start a new ball with a new blade and change it frequently -
as soon as the cardboard edges fray.
ALWAYS cut away from your hand NEVER towards it.
I use red Tuck Tape to join the panels. Made for permanantly joining plastic vapour barrier, this is the ONLY tape strong enough to hold the balls together.
I use WELDBOND white glue - and often add a little water to make it more easily brushable.
the outside of the joins between the panels with 2 inch brown paper strips - I brush WELDBOND on to the strips and then press them in place. The strips are cut from yard waste bags. These bags use a double layer of strong paper, so one bag gives
lots of strips. The strips do not usually lie flat when first laid down - they cockle and crinkle. If you use a hot iron about 20 minutes after the strips have been placed - you can elininate most of these irregularities to get
a completely flat surface.
I use latex paint with primer incorporated. It usually takes two coats for sufficient coverage.