I picked up an old Waltham diver and it needs a new crystal. I am relatively new at watch repair but I am capable enough to remove a movement from its case etc. When I took it apart the crystal was pretty much hanging on by a small piece and I kinda finished it off. I would also like to replace the back gasket and it there was one on the stem. Also is there some type of glue used to seal the crystal or are they just pressed in? Sorry about the questions bear with me I'm new to the hobby. I tried to upload a picture but the file is too large Any help would be great!!