I might suggest that the corners flaking off are a result of using a razor blade to trim and finalize the print for dry mounting. I used to use a razor blade and metal straight edge to trim prints and I would on occasion see the corners chip off either before or after dry mounting.
Originally Posted by John Simmons
Some years ago I purchased a Roto Trimmer, I said then and still say now, the single best purchase I have made for my photography in the past 15 years. I have not seen a chipped corner since.