Couple of weeks ago I have shared with you my experience with soft weights. I needed them during construction of false rounded spines for a box project. Today I would like to share my thoughts on making those false spines.
By initial impulse, I thought to carve wooden pieces to form rounded spines. However, the boxes had to be 13 cm high (customer changed the order to 7 cm high boxes later), and these false spines would have been too heavy. At least I think they would.
The other option was to round a light board or a heavy paper with forming tool like those I am selling at my Etsy store.
I do not see any problem making the grooves wide enough with my router to accommodate for the needed box height. However, with any lightweight cardboard I would definitely need to reinforce the curved spine somehow.