Liquid hide glue works but it has a shelf life. If it is old it takes forever to dry.
Hide glue is water soluble and not good to seal things. You can use TBIII to seal it because when it dries it is waterproof.
For a more primitive sealer I use pitch varnish I make to seal hafted points on arrows. The pitch varnish is just hard brittle pitch dissolved I alcohol then strained before using.