If you skip this step, there is a high probability that the pages will eventually fall out of the books. Select some thermal binding cases for your yearbooks. If you want to use cases that have been foil imprinted and/or have window cut in them, you will want to order the cases well ahead of time. (A few months will probably suffice. Although you might want to give yourself extra time to prevent any disasters from occurring.) Make sure that the cases can easily bind all of the pages of the document. If the case is too large or too small, pages will fall out of the yearbook at some point. Turn on your thermal binding machine and let it warm up. Place a yearbook in each one of the binding cases and make sure that the pages are flush. All of the pages need to come into contact with the adhesive in the case's spine. Once your machine has warmed up, place the yearbook in the feed opening with the spine facing down. Depending on the length of your yearbook and the size of your machine, you may be able to bind more than one book at time. If you can do this, you will save a lot of time and finish the job faster. Your thermal binding machine will probably beep when it has finished binding your yearbook.
When this happens, remove the yearbook from the device and move it to a cooling rack. The adhesive need to 38mm PET preform completely cool and set before you do anything else with the book. Repeat the process in order to bind your other yearbooks. Turn on the binding machine when you are done so it won't overheat. One thing you might want to consider if you choose to bind your own yearbooks is to have more than one thermal binding machine at hand. This will speed up the process since more than one person will be binding. Granted, you will need to put out some extra money for another machine, but you'll recoup it by not needing to send your books out for binding by a third party. It's easy to bind your own yearbook and it can definitely be cost-effective. Give it a try. Good luck and happy binding!