Epoxy would work pretty well for a finish
I can't guarantee it but Titebond III is some good stuff, I keep a 5 gallon bucket about half full of water in my shop now to keep wet rags in to wipe off excess glue.When I first started using Titebond III I would rinse the wet rags out and hang them on the slop sink, and they would harden over night as they dried. No matter how much I rinsed them they would still be as stiff as a board the next day hence the 5 gallon bucket
I have had one of the stiff rags soaking in the bucket for over 3-4 months, and it is still as stiff as the day I put it in there so it is some pretty water proof stuff
I can't guarantee it but Titebond III is some good stuff, I keep a 5 gallon bucket about half full of water in my shop now to keep wet rags in to wipe off excess glue.When I first started using Titebond III I would rinse the wet rags out and hang them on the slop sink, and they would harden over night as they dried. No matter how much I rinsed them they would still be as stiff as a board the next day hence the 5 gallon bucket
I have had one of the stiff rags soaking in the bucket for over 3-4 months, and it is still as stiff as the day I put it in there so it is some pretty water proof stuff