"Things I Found On Wikihow.com That Amuse Me", part 3 of a trilogy.
This is one I actually intend to do. [I never did, but my brother made one for me.]
How to Make a Hollow Book
A hollow book can be a nifty way to hide something, whether it's a spare key, a secret note, or even money. Most people wouldn't think to browse your library for private or personal things. It's also a great way to pass something to someone discretely--an unsuspecting onlooker will just think you're sharing a very good read!
Steps
- Select a book, preferably a thick one with a sturdy hard cover. Make sure that you own the book. Never use one that belongs to either the library, a friend or a family member. Rummaging through books at either yard or garage sales might allow you to find a book with the proper thickness for your particular need. Libraries often have a section with old, used books for sale, and for very little, you can buy great hard-covered books.
- Select the first few or as many pages as you want and hold them to the cover with a rubber band so they do not get messed up with the glue. These, except for the last one of these pages, will not be cut out. This will allow the book to look like a book when it is opened up and will cover the hole itself. The page nearer the hole will be glued later on and explained in the last step.
- Mix a solution of white glue and water. Make the consistency just enough for the glue to be runny, and absorbed by the edge of the book's pages. 50% to 70% glue (30% to 50% water) or half a coffee canister full usually works well, but use your judgement given the thickness and size of the book.
- Hold together all the pages after the one you set aside earlier and brush the edges with the glue solution so that it is reasonably absorbed. This will hold them together.
- Let the book dry for fifteen to thirty minutes. Place two or three sheets of wax paper in between the glued pages and the page(s) (if any) that will not be cut (including at least the previously selected page and the front cover) so that they do not touch and stick together. Place something heavy on top of the front cover so as to apply pressure.
- Open the book to reveal the first glued page. Draw a half-inch border within the edge, on all four sides (including the spine).
- Cut along the inside of the drawn line with a straight edge knife (a box cutter works especially well). Try to make the cut as vertical as possible, or else try to tilt it so the hole will narrow as you go down. Using a ruler, as shown in the image, can help a lot. Apply enough pressure to cut a few pages at a time.
- Continue cutting through the layers. Do not rush this step, because the slower and more carefully you do this, the smoother and straighter the inside edges will be. Remove the bits of paper from the inside that accumulate from the cutting.
- Brush the glue solution onto the inside edges of the hole and allow it to soak in. The glue dries clear, so if it drips a little, do not be concerned. While waiting, apply a second coat of glue to the outside edges of the pages.
- Brush the "frame" of the hole with a light coat of glue. The saved page will be glued directly on top of the hole, essentially covering it (for now).
- Close the book again, this time without any spacers. Allow it to dry for about 15-30 minutes. In this drying phase, the saved page will become affixed to the hole, as mentioned in the previous step.
- Cut the saved page along the edges of the hole so that the hole is visible and accessible once again. The insides of the book may still be moist because the book had been closed while drying. Now is a good time to let the book dry while it's open.
- Check to make sure every part of the book is thoroughly dry. Touch it with your fingers, and when you are certain it is dry, fill it with your treasured items, shut the book, and put it in the bookshelf. Only you will know that this book has a compartment because it will be surrounded by many other books!
Tips
- Utilize the book as you continue to work on it by storing some personal items inside while you take a break. This gives you a feeling of accomplishment that will help you complete the project.
- If you ask what is the purpose of saving the last page to glue on top, and then cutting through it just like the others?" It's to cover up the lines you initially drew to cut the book apart.
- Make sure you only use a hardback book. If the cover is soft, you will end up cutting through the back of the book.
- When you place the 'hollow book' into the bookshelf, make sure you remember the name of the book!! If you forget, you may never know how to find the book, unless you remove all the rest of the books.
- The Dremel tool makes quick work of 30-40 pages at a time, and sometimes the heat of the cutting disk burns the inside edges, leaving smooth brown lines on the inside.
- This is a novel idea - put three books together!! The Books are glued together, and then the covers as well at the pages were cut through. This provides two advantages. #1) You could potentially make your "secret hollow book" as deep as you want it, and #2) looks cool on the bookshelf, as it looks like you simply have a bunch of books pushed together, and only you know the truth!
- Multiple books can be held together with long skinny bolts. Use a template to cut through each book separately so the knife or Dremel tool will reach. Leave the back cover open on the last book, and drill through the book corners and countersink for the bolts before gluing the back cover on.
- Some people have suggested other things to put in a hollow book, like a hidden wireless router or a hidden teddy bear.
- It is best to use a book that people think you might actually read. (But not so interesting a title that they might want to take the book down and flip through it.)
- Use a metal ruler (or a wooden ruler with a metal-edge insert) to guide your knife. The illustration pictures a plastic ruler, but the knife can easily bite into plastic (or wood), messing up both the ruler and the project.
Warnings
- Pay close attention when you're cutting the pages. The last thing you want is a hollow finger and a bloody book!
- Make sure you're not destroying a potentially valuable book, or one that you may want to read some day!
Things You'll Need 
- Hardcover book
- A second book in case you mess up the first
- Elmer's white glue
- Plenty of food to keep up your strength
- Container to hold glue solution
- X-acto knife, or box cutter. Both if you have them
- Brush to apply glue solution
- Rags to wipe up any spills
- Pencil
- Pen
- Extra ink refills
- Ruler
- Table to work on
