OH , Yes so familar. I bought a sharpener at Joann's also and it does work quite well , but if you are doing quite a few layers at a time you may bend or should say warp the blade then it does not help sharpening the blade. I made , the old fashion pie carriers for a scenic drive last month and they are very thick , it is easy to put to much pressure on the blade and it warps . Needless to say when I came back from Illinois I had to buy more blades. Trish