Pyro adhesive is a form of cement, that can be used for filling cardboard tube end caps, which have first glued on tube with white glue. It is water soluble and adheres well on paper.
Some recipes for pyro adhesive:
Calcium carbonate should be in pure form. Some of the 'whiting' type chalk powders may contain ingredients that react with water glass resulting in immediate hardening of the mixture.
Pyro adhesive is best made by first sieving powders togheter and then screening them togheter to shallow tray containing measured amount of water glass. The adhesive can then be mixed well and applied with a spatula.
The drawback of pyro adhesive is, it degrades slowly upon storage.