PE, in theory can i add a little whiting to a 1% cmc solution to make the cmc "harden" and become insoluble in water similar to adding glyoxal to gelatin? it would be nice to not have to use glyoxal or heat up gelatin to size papers with. It coats very nice and dries relatively fast and would be a nice substitute. I know you can't answer definitively because you can't test it yourself but is the "theory" sound?

Holmburgers, I know what you mean about it making a nice glue. Sometimes at work I have to use a pipe wrench to open the screw top lid that I store the cmc solution in for my glazes
I did read that paper conservation article you referenced while I was googling cmc. It seems to have many uses but doesn't seem to have many practitioners in the alt photo world - there must be a reason...