Chose linen thread over polyester for a 400 page rebind and I think it was the right call
Rebound a family bible last month. 400 pages, super thin paper, sewn on five cords. The old spine was gone and the signatures were barely holding. I stood in my shop for 20 minutes holding two spools. Bonded polyester on one side, Irish linen on the other. Everyone online says polyester lasts forever. But this paper was soft and old, and I worried stiff thread would chew through the folds after a few openings. So I went linen, 18/3, beeswaxed it myself. Took me three nights to sew it up instead of one, since linen frays if you look at it wrong. But the spine has that flex I wanted, pages lay flat at the third signature, and the whole thing feels like it breathes. Drop tests on my bench, no cracking at the joints. Curious if anyone here has switched from polyester back to linen for older books, or if I am just being sentimental about thread.