How to Make a Cardboard Hermit Crab Costume

Introduction
It is often difficult to find a costume for events such as a Halloween costume party. If you look for a costume in a store, it will be very expensive. The solution to this problem is to create your own costume. This Instructable offers a creative and simple costume design. The costume will be made out of cardboard only with no fasteners, so it can be taken apart and the pieces can be stacked. This allows the costume to be easily stored. It is also eco-friendly, because the only material is cardboard. This was a school project for a Problem Solving and Design Course, and all of these factors had to be taken into account. This costume is a good way to save money and still have a creative costume.

Design Brief
A costume can be designed and instructed at a cheap price, and also be environmentally friendly. Design a hermit crab costume using cardboard and slotted construction that can be made for middle school aged children and is safe. Make a the design a flat pack, meaning it can be taken apart and stacked with only flat peices. This allows for the costume to be stored easily. Create the costume to be used for Halloween.

Specifications
This costumes specifications include:
- The only material that may be used is cardboard.
- Pieces must be assembled using slotted construction.
- No adhesives of fasteners are permitted for use.
- Parametrics and ergonomics must be considered, because the costumes are being designed for children of age 10-13.
- A flat pack must be created with the pieces of the costumes, meaning all pieces must be flat so they can be stacked on each other.
- Any costumes must be safe for age range.

Limitations
This costume is limited to:
- The costumes are being designed for children of ages 10-13, therefore correct measurements must be made based on the average size of children in that age group.
- A costume cannot limit a child’s peripheral vision, mobility, and it must have proper ventilation. -The costumes must be safe enough so a child can use it with little supervision.
-The costume must be visually appropriate and have a marine theme.

Materials
Supply List
S1: Single-ply Cardboard (two 32" X 45" X 5" television boxes), Quantity: 4, Size: 20" X 30" (based on the average size of a 10-13 year-old.)

Tools and Equipment List
T1: Cutting Mat, Use: To cut cardboard on.
T2: Utility Knife, Use: To cut cardboard.
T3: Ruler, Use: To measure pieces.
T4: Pencil, Use: To score cardboard.

Step 1: Part P1: Backside

All cutting done on a cutting mat (T1) and all measuring done with a ruler (T3).

1. Measure and score a 20” X 30” rectangular piece of cardboard (S1) using a ruler (T3) and pencil (T4).
2. Score a curvature with a pencil (T4) from the top right corner to the bottom right corner of the cardboard (S1) indenting 2” in the center of the curve.
3. Score an 8” vertical line from the bottom left corner of the cardboard (S1) with a pencil (T4) and then begin a wide, even curvature until the mark reaches the top right corner of the cardboard (S1).
4. Score a 16” long curvature (Slot A) with a pencil (T4) conforming to the shape of the mark made in Step 3 that is 2” to the right of the mark and 2” above the bottom edge of the cardboard (S1).
5. Score a 4” long curvature (Slot B) with a pencil (T4) conforming to the shape of the mark made in Step 3 that is in the top right corner 2” to the left of the mark made in Step 2 and 2” below the mark made in Step 3 on the cardboard (S1).
6. Score a 16” long curvature (Slot C) with a pencil (T4) conforming to the shape of the mark made in Step 2 that is 2” to the left of that mark and 2” above the bottom edge of the cardboard (S1).
7. Cut out the organic, triangular shape, and cut along all other scores made for slots with a utility knife (T2).

Step 2: Part P2: Side Slot Pieces

All cutting done on a cutting mat (T1) and all measuring done with a ruler (T3).

1. Measure and score a 20” X 30” rectangular piece of cardboard (S1) using a ruler (T3) and pencil (T4).
2. Score two 9” X 14” rectangles with a pencil (T4) on the 20” X 30” piece of cardboard (S1).
3. Cut out the 9” X 14” rectangles with a utility knife (T2) along the marks made.

Step 3: Part P3: Top Slot Piece

All cutting done on a cutting mat (T1) and all measuring done with a ruler (T3).

1. Measure and score a 20” X 30” rectangular piece of cardboard (S1) using a ruler (T3) and pencil (T4).
2. Score one 9” X 3” rectangle with a pencil (T4) on the 20” X 30” piece of cardboard (S1).
3. Cut out the 9” X 3” rectangle with a utility knife (T2) along the marks made.

Step 4: Part P4: Frontside

All cutting done on a cutting mat (T1) and all measuring done with a ruler (T3).

1. Repeat all steps for P1.
2. Score six 1” lines (Slot G) with a pencil (T4) that are 1” apart from each other, and 2” above the bottom side of the cardboard (S1), with the first line to the left being 4” right of the left mark, and the last line being 4” right of the right mark.

Step 5: Part P5: Legs

All cutting done on a cutting mat (T1) and all measuring done with a ruler (T3).

1. Measure and score a 20” X 30” rectangular piece of cardboard (S1) using a ruler (T3) and pencil (T4).
2. Score six 1” X 4” rectangles with a pencil (T4) on the 20” X 30” piece of cardboard (S1).
3. Score an organic curvature of the legs according to the working drawings with a pencil (T4) (ATT: Orthographic View).
4. Cut out along all marks made with a utility knife (T2).

Step 6: Part List (ATT: Orthographic View)

Part P1: Backside, Quantity: 1
Part P2: Side Slot Piece, Quantity: 2
Part P3: Top Slot Piece, Quantity: 1
Part P4: Frontside, Quantity: 1
Part P5: Legs, Quantity: 6

*If necessary, increase the scale shown on the Orthographic View (1 in. = 8 in.). The scale is relative to the size of an average 10-13 year-old. Pieces can also be cut to the size of your body, if you do not want to measure them.

Step 7: Steps for Assembly (ATT: Exploded View)

Refer to this drawing to complete the 8 assembly steps.

Step 8: Assembly Step 1

1. Curve a Top Slot Piece (P3) to conform with the shape of Slot A on the Backside (P1).

Step 9: Assembly Step 2

2. Insert a Top Slot Piece (P3) into Slot A on the Backside (P1) with the shorter side of 3” on the Top Slot Piece (P3) being inserted into the slot.

Step 10: Assembly Step 3

3. Curve a Side Slot Piece (P2) to conform with the shape of Slot B on the Backside (P1).

Step 11: Assembly Step 4

4. Insert a Side Slot Piece (P2) into Slot B on the Backside (P1) with the longer side of 14” on the Side Slot Piece (P2) being inserted into the slot.

Step 12: Assembly Step 5

5. Curve a Side Slot Piece (P2) to conform with the shape of Slot C on the Backside (P1).

Step 13: Assembly Step 6

6. Insert a Side Slot Piece (P2) into Slot C on the Backside (P1) with the longer side of 14” on the Side Slot Piece (P2) being inserted into the slot.

Step 14: Assembly Step 7

7. Insert the Top Slot Piece (P3) protruding from Slot A on the Backside (P1) into Slot D on the Frontside (P4). Insert the Side Slot Piece (P2) protruding from Slot B on the Backside (P1) into Slot E on the Frontside (P4). Insert the Side Slot Piece (P2) protruding from Slot C on the Backside (P1) into Slot F on the Frontside (P4).

Step 15: Assembly Step 8

8. Fold the six Legs (P5) 1” below the top edge to create Tab A. Insert Tab A on the Legs (P5) into Slot G on the Frontside (P4).

Step 16: Painting the Costume

If desired, you can paint the pieces to resemble a real hermit crab shell. Keep in mind that if you paint one side of a piece of cardboard, it will warp. To avoid this, paint both sides of all pieces, so they stay rigid.

Step 17: Wearing the Costume

When worn, the costume is on your upper body. Your head should protrude from the gap between the Top Slot Piece (P3) and a Side Slot Piece (P2). Your arms should protrude from the gaps between the Top Slot Piece (P3) and the Side Slot Pieces (P2).