Who knows, maybe there is some marginal benefit against lifting a splinter with certain finishes applied. I don't personally believe it would amount to much protection, but it could add a bit I suppose. I think the bigger point about this question, and the reason most folks quickly responded with a "NO", is pretty clear. If built correctly, no finish is needed for that purpose. If built incorrectly, the finish wont matter much at all. The bow will break down or come apart at some point. Yes, CA glue is a very good component to use as a spot solution, cracks, knots, checks. But we are talking about strengthening a known weak spot on a bow (or gun stock). If the known weak spot is the back, you will get much more mileage out of simply improving your selection, design and execution. I think you will find it much more satisfying as well. You had mentioned that a good number of bows have broken on you. Welcome to the club. Do a good post mortem on any that break, and identify what that cause likely was...Selection....design....execution. Make the proper adjustment on the next one. I seem to remember Jim Hamm talking about sinew backing all of his early bows just to keep them from breaking. At some point he no longer needed to do that. Welcome to PA.