A lot of the material we already had around the house so it didn't cost us anything but my time (about an hour) to shape and design the box. We plan on "burying" the gift somewhere in his house (we live in a city, no yards!) and we'll give him a treasure map of the floor plan to find it.
I had fun creating it and didn't stress about perfect corners much (he'll be four!), so there are no real measurements here. I'd love to hear how you modified this idea to suit your needs.
You'll need materials. I gathered:
a large cutting mat (something to protect your surface)
a box cutter (sharp blades really help)
a cardboard box (we recycled a rectangular medium shipping box)
roll of 1/2" wide double sided tape
roll of 1" wide black duct tape
thin point sharpie marker
12" L metal square ruler
clear scotch tape
approx 3ft x 1ft of brown craft paper
wide felt black and brown markers
a brown colored pencil
gold metallic marker
a gold metallic gift bow
some shiny yellow/gold plastic baubles
yellow/gold gift paper
First find a box that your gift sits nicely in.
Step 1: Step 1 - Create Your Curved Top
Just above the "gift line" insert your sharp box cutter blade into each corner of the wall and cut up to the top. Be careful to position yourself so if your blade slips you don't stab your arm or eye, this is a pirate party not a slasher film.
Bend the cut walls over the gift line, you'll see the flaps of the cover meet neatly across the gift and already form the treasure chest dome effect. Hooray!
Step 2: Step 2 - Fix Those Flaps
Now you've got your dome but the sides are all wrong. You could cut the flaps off entirely but it would be nice to give the cover the extra support flaps provide. So we need to trim and re-fold them.
First, hold your "dome" in place gently to get the correct arch that occurs when the top flaps fold nicely over each other (see the second photo in Step 1). Trace this arch against the inside of your flap walls.
Rotate your box flap side down on your mat cutting board, using your L square ruler draw straight lines from the bend in each arch line to the top of your flap (do this on both sides).
Use your box cutter to cut those ruler lines.
Now you have three flaps on each side, two new narrow side flaps and one wider center flap. Cut the two new narrow flaps on each side along the natural fold of the box wall. CAREFUL :: DO NOT CUT THE CENTER FLAP. See photo #4 here.
Fold each short narrow flap at a sharp angle into the box. See photo #5 here. Use the dull side of your box cutter to perforate the inside of the cardboard if necessary. CAREFUL :: DO NOT PUSH HARD WITH BLADE WHEN PERFORATING.
Use the ruler to draw a line connecting the top corners of each folded narrow flat across the wide center flap. Fold the two wide center flaps along this line, this will allow the center flaps to meet neatly together when folded. Again, use the dull side of the blade to perforate the cardboard to assist you in making a neat fold.
You should finish with the beginnings of a simple treasure chest (last photo).
Step 3: Step 3 - Create a Place for Your Treasure Chest Lock
Cut one long wall flap along it's fold line, remove. My cut wasn't very neat so I decided the rough edge of the severed flap would go on the inside and I would use the nice box factory cut side as my lock edge.
Placing the severed flap down on your cutting mat trim off the rough edge leaving approx 1 inch of material.
Place one strip of double sided tape along the bottom side of the new 1 inch flap. (I put the tape on the bottom of this flap so the front of my cover would have a smooth edge). Burnish the tape with the smooth bottom of your box cutter, remove the backing and add another strip to completely cover this bottom of the new flap with double sided tape (if you are using 1 inch double sided tape you don't need to repeat this, I was using 1/2 inch). Burnish and remove backing.
Tape the 1 inch flap of the severed edge onto the top of cut edge of the remaining wall fold. See photos, you now have a long domed cover that opens on one side.
When you hold your cover closed you'll notice there is an "overhanging lip". Holding the cover shut, use your sharpie to mark where the front outer wall meets the overhanging lip underneath on both sides. Flip your box over on to the mat cutting board, use the L ruler to draw a straight line connecting these dots. Use the dull side of your box cutter to perforate this line.
Now when you close your box you can fold the overhanging lip down and have a place to "put your lock".
Hooray, it's starting to feel like a treasure chest!!
Step 4: Step 4 - Paper Your Box (part 1)
Here's how I did it:
First, I told myself I was doing this to impress a small child, not the parents who would be in attendance. So again, I'm not too concerned about perfect edges or corners.... but I have my pride and you'll see where that comes into play.
Second. since I had a long sheet of brown craft paper I decided to wrap the length of the box first. Length here = top of the front wall, under neath, up the back wall, across the dome over and under the lock lip. I will cover the sides later to disguise my paper tabs.
When I severed the wall fold to make my lock lip in the last step my cut was uneven. To mask this I folded the edge of my craft paper over, applied double sided tape along the inside and outside of my front outer wall top edge, cut the paper where the domed sides meet the front, and tape the folded paper over this - violà, a clean edge!
Now fold the paper under and around the box. Use your traditional gift wrapping skills to create neat corners and double sided tape to discreetly pin these edges down. Don't worry about covering the sides but do wrap the paper around the side wall edges by a few inches.
When you get to the front top edge (the lock lip) add approx two inches of paper and cut the rest off. Fold these extra inches over, double tape both side of the lock lip cardboard edge and adhere your paper.
I also wrapped the edge of the paper around the edge of the cardboard on the domed cover using the double sided tape.
You should end with a seamless paper box across the top cover and down the front and back.
Step 5: Step 5 - Paper Your Box Sides (part 2)
I had exactly enough brown craft paper left to cover the exact length and width of each panel. It was weird since I didn't pre-measure, but anyway...
Using half of my remaining paper, I folded a very narrow cuff along the bottom, top and sides of the paper "panel" - because again, my cutting hadn't been perfect.
Add double sided tape along the edge of your wall but leave about 1/4 - 1/2 inch from the actual edge... this is in case your paper panel isn't exactly square.
Add double sided tape along both sides of the angled top folds inner cut, and wrap the tape around the top edges by about a half inch. See first photo.
Burnish tape and remove backing. CAREFULLY place your paper side panel.
Use your gift wrapping prowess to cut along the top flaps, I did NOT cut the paper inside the angled flap seams, see photo 2.
Fold paper over the edges and add tape to adhere. I had JUST ENOUGH paper to barely cover the top edge of the long flap.
Repeat on both sides... you should end with a lovely paper treasure chest.
Step 6: Final Step (the Fun Part) - Decorate Your Pirate Treasure Chest!!!
I began by adding my yellow/gold gift paper, my gift and draping some shiny yellow/gold plastic baubles over the front wall of the box (pirates are always spilling their gold, aren't they?). I adhered the inner end of my bauble to the gift and covered that with a gold metallic gift bow.
Anything else going inside the box should be added and secured now because we're going to "lock" the box and we'll need to flip it around during the decorating.
I used 1 inch black duct tape to seal my box. Starting under the bottom of the back, I taped one continuous piece of black tape along the left and right edge of my box, leaving several inches hanging over the lock lip. Bring another continuous piece of black tape from the bottom front of the left and right side to the top of the front wall. I folded the long hanging edges of the first piece of tape over at the ends to make a sort of "easy release" tab.
Use several short cuts of black tape in a box shape across the center of the front to really "lock it". I know, it sort of looks like Charlie Chaplin right now but we'll fix that with our black and brown wide felt markers.
Using the black marker draw your border edges, be sure to add circles for your gold "bolts" before filling in the black.
CAREFUL :: don't forget to draw your keyhole!!
Use the brown marker to create your wood planking. Use your brown colored pencil for wood grain.
Use your gold marker to create "bolts".
And we've got a great, recycled, budget Pirate Treasure Chest gift box any four year old should be excited to find "buried" in the hall shoe closet or bathroom cabinet of his home
*** With more time and material shopping you could get some other duct tape and do a great job making a real "lock"