Why I'm starting to think PVA might beat out wheat paste for tight back corners

I tried using PVA glue on a tight back corner repair last week instead of my usual wheat paste. The cover seemed to set faster at first, but when I checked it after 24 hours, the joint looked a little more rigid than I'm used to. On the other hand, that same fast set time saved me from having to clamp it down overnight. Has anyone else noticed a difference in flexibility between the two on older leather spines?

2 comments

2 Comments

blair59711d ago

Wheat paste has more give to it because it dries softer, which is why it works better on old leather that's already done most of its shrinking. PVA sets up harder and that can cause problems when the leather moves again with humidity changes. Had a similar issue on a 19th century law book where the PVA joint cracked right along the hinge after a dry spell. Switched back to paste on that one and the flexibility difference was noticeable right away. If you're in a hurry, PVA works fine but only on modern books that are already stable.

scott.jana11d ago

I remember reading a blog post by a bookbinder in New Mexico who had the same trouble with PVA and old leather. She said the dry air out there made the problem even worse because the leather kept shrinking and expanding more than in a humid climate. She ended up mixing a little methyl cellulose into her wheat paste to keep it from molding in the summer. That trick might work if you're worried about paste going bad before you use it all up. Her point was pretty much the same as yours though - old leather just doesn't like stiff glues.