I have myself geared up now for a weeks work on perfecting the pleated corner. I managed the first book I did, sort of ish, with a tutor over my shoulder. Managed several when doing the dos-a-dos style but have since shied away, favouring the box corner. I'm being pulled back to the pleated corner though as it seems more natural, less manufactured the box corner being a bit too 'right'.
I don't really understand either the art or the craft of turning corners this way it seems a bit like the sorcery associated with the weaver's knot. In an effort to reduce the variables I have cut leather and board all the same size and thickness and will pare the leather to the same thickness around 0.5mm.
This way I will know that the elements are all consistent and it's just the manipulation of the leather that I have to concern myself with.
More alchemy. Settling for wheat flour paste the reason being after searching the internet for a silly length of time encountering as many theories and discounted theories as there are stars in the sky, I finally looked in the books on the shelf. (sic).
Kathy Abbott's fine book: Bookbinding: A step-by-step guide, published by the Crowood Press in 2010, suggests wheat starch paste for paper, wheat flour paste for binding.
The paste I have used so far has been Shepherds paste, but who knows what's in it as it lasts such a long time.
Kathy's recipe is 1 Tablespoonful of organic plain flour to ¼ litre of distilled water to which I am going to add a small amount of ph neutral pva.
Anyway we'll see how it goes.