I work for a furniture company so I thought it'd be fun to make a transformer chair costume for our Halloween office party.

Step 1: Materials & Tools

The video above shows the chair in action. Make sure to check out the video at the end to see trick-or-treaters' reaction to the chair coming to life!

MATERIALS:

3/4" Plywood

Open cell polyurethane foam

Vinyl Upholstery

Leather Upholstery

Wood screws

Hinges

Adhesive Spray

Eye Hooks

String

TOOLS:

Orbital Saw

Band Saw

Drill

Staple Gun

Step 2: Body Dimensions

First I had to measure different parts of my body to figure out what dimensions to make the chair costume. Critical measurements were length and width of me sitting with my legs crossed, forearm length, chest width and depth, and sitting height.

Step 3: 3D Modeling

I 3D modeled the general shape of the chair with the dimensions I took to ensure that the proportions of the chair looked right visually before I started building. It’s not a model of the final product, but it boxes out the dimensions appropriately.

Step 4: Making the Arms

For the arms, I used a 4” diameter cardboard tube and cut it to the length according to the 3D model. I capped off the front end of each arm with small plywood discs.

Step 5: Wood Construction

I used an orbital saw and band saw to cut the wood pieces according to the dimensioned model. I joined them using wood screws and wood glue. The head piece had a hinge so that it could raise up. The front of the base also had a hinge so that it could swing out when I was standing up. After it was constructed, I put the costume on to make sure it fit right. The wood was a bit too heavy so I cut a large hole in the middle of the seat and covered it with Dymetrol, which is a structural webbing material used in lounge furniture.

Step 6: Harnesses

I had to be able to wear the costume so I created harnesses to strap the costume to my body. For the base piece, I measured my waist and created a plywood piece that sat on my hips. I lined the hole with foam (blue) so it would be more comfortable to wear. It hinged to the base with bolts so that it could swivel. For the top piece, I used backpack straps threaded through holes in the plywood. When I was wearing both pieces, I tied them together using a D-ring belt.

Step 7: Foaming

After the wood frame was fully constructed, I measured each panel that needed foam and cut the foam to size on a band saw. I used spray adhesive to glue the foam to the wood pieces. I made sure to cut a hole in the head piece so that I could see out of it (the leather had tiny holes in it so I could see through it).

Step 8: Upholstery

I measured all of the panels that needed upholstery and created upholstery patterns to be cut. I had more vinyl than leather so most pieces used vinyl. The seat cushion, chest piece, and head piece used leather. There were a few pieces that needed to be sewn together. However, since I don’t have a sewing machine and sewing leather is hard on the fingers, I opted to staple them together. I then attached all the upholstery to the foam and wood by using spray adhesive and staples.

Step 9: Pulley System

In order to be able to see better, I needed the head piece to raise when I was standing. Since my hands aren’t accessible in the costume, I needed it to raise automatically so I used eye hooks to create a simple pulley system. The string was tied to the head piece, looped through eye hooks in the wings of the chair, and then attached to eye hooks on the seat section. When I stood up, the seat piece would rotate down, pulling the strings, and raising the head piece. I used quick release S-hooks so that I could attach and detach it easily.

Step 10: Surprising Trick-Or-Treaters

I wore the costume outside of my house on Halloween. My wife sat next to me in a Banana costume in her own chair and when trick-or-treaters came up, she said "You can take candy from this bowl, or if you're brave enough, you can take candy from the Haunted Chair." Check out the video for some great reactions.