How to Make a Clamshell Box

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I’m making a bunch of clamshell boxes for the “fancy” edition of Dan Ivec’s book, On the Stairs. So I thoughts I’d share the fun, with a tutorial about how to make clamshell boxes. Enjoy!

 

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STEP 1: GATHER YOUR TOOLS
You will need:

  • ruler
  • sandpaper
  • knife
  • bone folder
  • pencil
  • brush
  • wood glue
  • pva glue (i dilute it with a little bit of water or methyl cellulose)
  • bookboard or chipboard – medium to thick
  • paper or book cloth to cover your box

STEP 2: MAKING THE INNER TRAY

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Measure the trays for the clamshell box directly from the object you’re building the box for, so it’ll fit nicely in there. To find the height and width of the inner tray base, take the size of the object and add one board thickness. In the picture above: the width of the tray base is the width of the object plus one board thickness. Cut these pieces using a straight edge and a sharp knife. The tray will need three walls:

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Once you have all of those cut out – and be sure to get your corners square – you can sand any rough edges down. Now you are ready to glue the pieces together for the inner tray!

Spread out some wood glue on a scrap piece of board like so:

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Be sure to put down some scrap paper so you don’t make a big gooey mess on your nice table! Place the edge of the base into the wood glue to get the entire edge covered evenly, wiping the excess glue off by tilting the board and wiping it against the piece of scrap as seen below. Then press the glued edge onto the wall piece you have just cut. You can secure it there with a bit of masking tape while it dries.

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Attach the other two walls in the same way, and then use some bricks or other weights to press the boards together until the glue dries, about 30 minutes.

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STEP 3: COVERING THE INNER TRAY

Now, get out your pretty pretty paper or book cloth, because we’re going to cover the inner tray. The paper or cloth for this part will have to be two times the height of the walls, plus 1 ½ inches, and then long enough to wrap around all three walls with ¾ to spare on either end.

Take your brush and spread some PVA glue onto one of the short walls of your inner tray, then press it down onto the strip of cloth so that closed side is ¾ inch away from the edge:

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Then flip it over & smooth out any bubbles with your bone folder. Continue in the same way for the other two walls, smoothing down each side with a bone folder as you go, until you have something that looks like this:

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Next, we’ll glue the bottom flaps onto the base of the tray. Pinch the corners and cut them with scissors, then glue the cloth down and smooth with the bone folder.

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You’re going to have to make some fancy cuts to make the cloth (or paper, if you’re using pretty papers) fit into the inside of the tray. I’ve made a couple of different diagrams of the cuts below.

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OK! Once you’ve got all those tricky cuts made, glue the tabs down in the following order:

Start with the open side of the tray, and then glue down the short walls before the longer wall:

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Your bone folder is your friend, really be sure to tuck the cloth into the corners. 🙂

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YOWZA: almost done with that part! But you’ve got to cover up that unsightly bookboard peeking out at you. Cut a piece of paper & glue in on there, pulling it over the edge & onto the bottom of the tray. The paper should be slightly smaller than your tray so it doesn’t go quite all the way to the walls, and it should be wide enough to overhang the open edge.

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Very nice.

STEP 4: THE OUTER TRAY

The inner tray fits neatly into the outer tray when the box is closed. The construction of the outer tray will be exactly the same as for the inner tray – hooray! The measurements for your boards are below:

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Follow the directions for the inner tray.

STEP 5: MAKING THE CASE

Cut your boards for the case. You will need two covers (front + back) and a spine.

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Cover height: Outer tray height + 2 board-thicknesses
Cover width: Outer tray width + 1 board thickness
Spine height: Same as covers
Spine width: outer tray wall height (don’t add anything to this or it will sit funny!)

Cover the boards with glue (PVA) and then place them glue-side down onto a piece of book cloth like in the picture above. If you’d like to cover the case in paper you can do that too, but it’s best if the spine is at least attached to the covers with book cloth, which is more flexible and durable than paper. Flip it over and smooth it out with a bone folder to get rid of any boops & bubbles!

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Use your bone folder to work the book cloth down into the creases.

Onward!

Cut a piece of book cloth about 1 ½ inches wider than the spine, and 1/8 smaller than the inner tray height. Brush the back of it with glue and adhere it to the inside of the spine, smoothing it out with a bone folder and working it into the creases:

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Put the finished case under a weight to prevent it from warping as the glue dries.

STEP 6: PUTTING THE THING TOGETHER!

Alright, this is the last step! Good job! You’re going to take the two trays you made and attach them to the case using wood glue for a super strong & sturdy box. Spread wood glue over the bottom of the inner case (the smaller of the two) using a scrap piece of board. Try and get the glue all the way to the edges without going over.

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Carefully place the tray down onto the case so that the inner edge is all the way up against the inner edge of the cover, with an even lip around the outside edges of the tray:

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Finally, spread wood glue over the bottom of the outer (bigger) tray. Place the outer tray upside down over the inner tray, and then close the outside cover over it. Press gently with your fingers, then carefully open the case up again. Everything should be in its proper position…

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Put some weights (or heavy books) in the open box for an hour, and then close the box and leave it overnight with weights on top.

Good luck!

8 Responses

  1. Jennifer

    Thank you for this tutorial. I made one of these before but my notes are bad. I’m going to give it a try!

    • rebecca elliott

      Yes, I find the wood glue is stronger so it works well for keeping the boards together.

      • Anita

        Thanks for the reply!! I just saw that you answered 🙂
        Do you know if it is acid free?

  2. Rhonnie

    Where do you get your book board? Can you tell me the thickness of it?

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