I go carp fishing and one of the ways to bait up is using pva bags, the reason we use pva bags is when pva has set and applied with water it turns soluble again so soon as water or any water based material like plaster touches it it reacts back to a soluble state again, but at the same time when it dries its like a glue, the purpose of bond-it or wickes bonding agent is completley different when it dries it dont turn soluble again and stays solid with its grit almost like sandtex well it might be the same as sandtex gives you an awsome key to skim.