It starts by getting a pad of 200g A4 watercolor paint paper. I could not find one so I bought a A3 pad and cut it in half. For the covers I used scrapbook pages.
Each book is made from 10 A4 pages folded in half, giving me 40 sides to paint on. The covers are cut to about 2.5 mm bigger on all sides of the pages.
I reinforced the spine of the cover with a 50mm wide book binding tape on the outside.
The pages was marked at 35 mm intervals that will give me 5 holes along the spine. I used my sewing machine to punch holes through the markings. The thread is tied at both ends. To add the cover the process is repeated, with the cover added. The thread ends are trimmed off.
When the paper is folded, the ends form a V shape that makes it difficult to flip through the pages. This is trimmed to a strait edge when folded.
I find the ends of the book gets quite frayed as the cover is not as resilient as leather of cardboard. A strip of packaging tape is added to the edges of the cover on the inside.
All the corners of the pages and covers are punched with a quarter round punch giving a neat finish to a great sketchbook.