The most commonly used glue for book repair these days is Polyvinyl Acetate (PVA). Also known as craft glue or wood glue, PVA is a good all-around adhesive. It has a low moisture content and dries quickly. It dries flexible, so it can be used to tighten hinges, repair book cover corners and reattach loose book cloth to book board.
Importantly PVA is not affected by mold or fungi. However, it is damaged by freezing, so many US and European book repair supply houses will not sell PVA by mail from October to March. If PVA freezes, it separates and loses its adhesive properties.
PVA can be thinned with water or thin wheat paste for different consistencies and effects.
- Thinning PVA with water adds moisture and does not add any additional adhesive properties while thinning with wheat paste adds the adhesive qualities of the paste to the glue.
Many book binders or repair technicians use a 50/50 mixture of PVA and wheat paste strained through a sieve. You may find different adhesives or mixtures of adhesives by further internet research.
PVA glues cover a wide range of brand names and not all are used to repair books. For instance Elmer’s glue is technically a PVA but is not flexible when dry so it has limited use for repairing books. You may decide to have a few brands to cover the different types of repairs you are carrying out on your books.