Reply To: Staining & Gluing

In several of his videos Mr. Tom Fidgen applies various stains and finishes (such as iron oxide, shellac, and bog oak) prior to gluing up. Other woodworkers go to great lenghts in protecting the joint surfaces when applying shellac before gluing-up.

Hide glue and PVA glue undergo cohesion by dissipation of water, which probably would hindered by an occlusive finish like polyurethane varnish and paint, but perhaps not by stains or shellac, as they are more forgiving in allowing water to penetrate.

As for the adhesion of the glue to the pieces that are to be bound, there seems to be relatively small amount of evidence.

https://www.explainthatstuff.com/adhesives.html