When should I consider using PUR versus regular hot melt glue for perfect binding?

PUR glue is recommended when you have printed pages within a book that have heavy ink coverage (especially blacks & blues) and/or varnish bleeding into the spine of the book. It is also recommended on types of books that require more durability due to repetitive opening and closing. You may also want to consider using PUR glue on books that have the inside pages printed on wrong grain paper. Books that are printed on 100lb. coated or heavier and are wrong grain MUST be bound with PUR glue. Also see the PUR Service Description page- wrong grain, heavy text pages, heavy ink coverage, long term use, high usage book, coatings not knocked out etc…