Why you should never wax a thread before testing it on scrap, a hard lesson from a bindery in Baltimore
I was finishing a run of 12 case-bound journals for a local shop and grabbed a spool of linen thread I had waxed the night before with a new beeswax blend. The binder next to me, a guy named Walt with about 30 years on me, watched me sew the first signature, then put his hand on my arm and said "stop, smell that." Turned out the wax had a solvent base that was eating into the paper at the fold, and I would have baked that damage into all 12 books if he hadn't caught it on the second pass. He told me he learned the same way in 1994 when he lost a whole prayer book run to a bad batch of paste. Now I keep a scrap stack by the bench and test every new supply for a week before it touches a real job. Has anyone else had a supplier change a formula on them without saying anything?