I have a Nikon F, circa 1970-1972 which except for the light leak is a fantastic camera. The F doesn't have a door but the whole back slides off to load the film- The leak appears to be coming from the bottom based on the streaked negatives. I am wondering if there is some goo, foam, or tape I can use to seal the back back better. It *appears* to seal nicely but clearly it isn't.. I suppose in worst case I can tape up the seam with electrical tape but would prefer to stop the leak entirely if possible. Thanks!