Have you ever wanted to rock an awesome nerdy backpack at a con, school, or out in public? Perhaps you'd be interested in a Super Mario Bowser/ King Kooper turtle shell backpack? I originally made a turtle shell for my friend's Bowser costume. Well, once pictures showed up on the internet, some people contacted me and asked me if they could have the turtle shell, but made into a backpack. How could I deny such a awesome request?! I'm going to show you how I make them. Let's get started!
- EVA foam
- Green felt
- Dark green felt
- Red felt
- White felt
- Exacto knife
- duct tape
- Hot glue/ glue gun
- tape measure or ruler
-large sheet of paper
- Long baggage zipper (You can go to a thrift store, buy a really cheap bag and rip out the zipper)
- 2 or 3 3/4 inch pipe insulation tube
- Backpack straps (You can go to a thrift store, buy a backpack, and rip out the straps)
Step 1: Measurements and Base
1. You need to measure the size of the backpack so measure from the back of your neck to the bottom of your waistline. Then you need the width of your back, which is usually about armpit to armpit. (pic 1)
2. Transfer the measurement onto the paper and fold it in half vertically and then horizontally.
3. Cut out a curve and then open up your paper. You should have an "oval" type shape now. You can re-adjust it as needed. (pic 2)
4. Take your template, transfer it to EVA foam, and then cut out the oval from it.
5. Now take your EVA and cut a long, wide strip to go vertically down the middle of the shell. Determine how bulbous you want the shell to be at this point and glue the strip onto the oval template. You WANT to glue the strips a bit over the edge of the oval to create a lip. You can use your heat gun to warm the EVA foam to have it bend a little bit if easier. will allow the pipe insulation foam to have a lip to glue onto. From there, repeat the process so you have a strips that goes horizontally. Then repeat the process for diagonal strips. Your shell should look something like this now (pic 3).
6. Take your EVA foam and start filling in all the gaps. (pic 4)
7. Take your insulation tubing and measure it out around the shell. DO NOT glue that in yet. (pic 5)
Step 2: Backpack Straps
1. Take your backpack straps and mark where on the shell you will insert them. This is all done on the underside of the shell (AKA the EVA oval part of your shell). I usually start with the top of the strips.
2. Take your zipper and wrap it around the shell to see where the zipper should sit and how long of a strip to cut out. An easy way of doing this is to the find the middle of the zipper. That should go at the top of your shell.
3. Cut about a 1/2 inch wide strip out from the perimeter of the shell to make room for the zipper. Glue in your zipper
4.Open up the shell and Cut slits for the top straps and then on the sides.
3. You can take felt and glue it onto the underside of the shell. I like to use white because it matches well with the white ridge you will add later. (pic 1)
4. Re-cut your slits into the felt, stick your straps through, and Glue the straps down.
5. You can now glue felt on the inside of the back (aka, the oval EVA piece). I like using a the green felt over a lighter color. It seems to match well and it won't get as dirty when used. (pic 2)
Step 3: Shell Tiles, Seams, and Border
1. Notice that your shell should have 10 green tiles: 4 running down the middle, and 3 on each side. (pic 1)
2. Create a paper template of the tile. Each tile running down the middle should be of equal size. I use chalk to draw the shell on my green felt (pic 2)
3. i then glue the center tiles onto the shell, BUT i do not glue down the edges.
4. Now glue on your side tiles. Note that they are NOT full pieces and you may have to adjust them a little bit to make them fit. Don't forget to glue your fabric to the bottom half, past the cut your made for your zipper. (pic 3)
4. from your dark green felt, cut long strips and glue them in-between each tile. These will be the seams in-between the shell tiles. The reason you did not glue down the tile edges of the green tile is so you can tuck the dark green strips underneath for a cleaner look. (pic 4 + 5)
5. once completed, your tiles should be done, and your dark green seams should be in as well. (pic 6)
6. Take your pipe insulation tube and encase it in white felt. (pic 7).
7. glue the insulation tube onto the lip of the shell that you created. (pic 8)
8. You can felt the inner part of the shell. This adds even more strength to your backpack. (pic 9)
Step 4: Spikes
1. I created another paper template to determine the size of the triangle i will need to create the spike.
2. Transfer the paper template onto EVA. I usually use 3-4 triangles per spike, depending on the size of my tile.
3. I use my heating gun, bend the foam a bit, and then glue all 3 pieces together to form a cone. (pic 1)
4. once i have all my cones completed, i paint them white. The reason being is that the spikes will still look dark once encased in white felt IF they are left the foam's natural grey color. (pic 2)
5. once all the cones are painted white, i encase them all in white felt.
Step 5: Red Spike Rings
1. Take your insulation pipe and split it along it's length.. so instead of one tube, your have 2 long half pieces of wood.
2. Using your pipe, measure a ring around the base of each cone. connect the ends of the ring with duct tape and hot glue. (pic 1 and 2) repeat for all 10 rings
3. start encasing each ring with red felt. (Pic 3)
4. Take your white cone and pop it through the red ring. secure it on the inside with hot glue. you now have a completed spike (pic 4)
5. Take some EVA foam and make a cap on each spike (pic 5). glue the cap in. This cap will be glued directly onto the green tiles of the shell. there is more surface area to glue onto the tile rather than relying strictly on the permitter of the red ring to glue on.
Step 6: Finished!
1. Glue your spikes in place and that should be game!
Some helpful things to note.
- This is NOT a real backpack, so treat it more like a prop. Do NOT put anything super heavy inside. It should be able to hold a few items, but it is not meant for heavy objects like gallons of milk or tons of text books.
- If you want to add a small pouch on the inside, you can. You would probably just need to cut a slit into the green foam to insert the pouch in.
- You are a lot wider now, but be cautious about going into tight spaces. You don't want to damage your spikes!
Thanks for checking out the backpack build. Give it a go, but if interested in having one specifically made for you by me, please feel free to contact me at Spicypandacreations@gmail.com