Pellicles also stop forming when the culture is very old and there's a stack of them in the jar. If you've got four or five layers, peel the bottom ones off and keep the newest.
Clay Bertram
@clay_bertram
Sole proprietor landscaper turned S-corp after my accountant sat me down. Happy to explain what actually changed and what did not.
It's normal for the sheet to look terrible while wet. Judging it before it dries is how people talk themselves into using less glue and getting a bad bond.
Did you round and back the spine? A flat-back block of 180 pages sewn on tapes is always stiffer than it looks. Rounding gives the sections somewhere to go when the book opens, and backing creates the shoulder the boards hinge against. Without it you get exactly the 90 degree wall you're describing.
Also check the grain hangs straight. If the centre front isn't perpendicular to the floor you can chase bust adjustments forever when the real problem is that the front is riding up.
Airlock or a loose lid? Not because an airlock prevents kahm, it doesn't reliably, but a jar you burp daily gets fresh air across the surface every time, and kahm loves that.
Different vote: long stitch. 160gsm is thick, so a coptic means a lot of sections, a lot of holes and a long fiddly sewing session that's easy to abandon halfway. Long stitch is one continuous line, you see mistakes as you make them, and it opens flat enough to draw across if you keep signatures thin. Three folded sheets per signature, not six.
Drop the float test entirely and use volume instead. A bit of starter in a straight-sided jar with a rubber band at the start line. You want peak height and the time it took, not a yes or no.
For future charity shop jackets: buy for the shoulders and the chest, alter everything else. Shoulder width is the one thing that's genuinely difficult and expensive to change, and it's what makes a jacket look wrong when it's off.
Warning from doing this badly once: don't spray it and don't flood it. One thin brushed pass, dry fully, then judge. I went heavy the first time and got a shiny plasticky surface that looks wrong and is now the thing a conservator would have to deal with.
One practical note if you ferment: 3kg of chillies makes a serious amount of gas in the first four days. Use a vessel with real headroom and an airlock, or burp daily, or clean your kitchen ceiling.
Ask specifically what the 45 covers. Some quotes include the hem, in which case doing hems yourself saves you very little and the whole calculation changes.
Weigh your feeds. A spoonful varies by a factor of two and you can't read a trend when the input keeps changing.
Third toile with three distinct problems identified and fixed isn't doing it wrong, it's doing it. The people who make things that fit are the people who did the toiles.
Normal for PVA. The sharp vinegary note is residual acetic acid off-gassing and it usually fades over one to three weeks depending on how thick you went and how much air it gets. Stand the book on its fore-edge with the boards fanned slightly open somewhere with airflow and it clears faster.
What isn't normal is musty or bready. If it smells sour-sweet like old dough rather than sour-sharp like vinegar, that's the wheat paste going off and it only gets worse.