How to Make an Optimus Prime Costume

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Things You'll Need

  • Large Cardboard Box (big enough for a child to fit inside)

  • Box cutters

  • Glue gun

  • Plastic folder sheets.

  • Long-sleeve black T-shirt

  • Black cardboard

  • Black or dark blue sweat pants

  • Spray paint (red, blue, yellow and silver)

  • Flame template

  • Elastic bands (2 yards)

  • Autobot logo (a Transformers symbol)

  • Duct tape

  • 2-liter soda bottle

  • 2 tennis ball cans

In truck mode

Making a transforming Optimus Prime costume will make your child the winner at any Halloween costume contest. Many kids want to be the Transformers hero and beg for the store-bought costume. But all will envy the ability for a robot to turn into a semi-truck. Following these instructions can save you hours of experimentation with how the pieces transform together.


Step 1

Ask the child to squat down on the ground with his forearms and shins level on the ground. His legs should be together and his arms against his body with his head looking up.

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Step 2

Place the box over him to make sure it is big enough to cover his body. Remove the box. Cut the front third of the box off, placing the rear to the side for later use.

Step 3

With the front flaps opening horizontally, remove the bottom panel from the box.

Step 4

With the child standing straight up, place the box against his chest. Draw the neck cutout on the top and arm holes on the sides, according to the size of the child. Note that the neck cut out will be circular, but the back of it will be open so that the subject can move freely. Trace the windshield. Remove the box from the child and cut the neck, arm holes and windshield.


Step 5

Refit to the child to see the fit. Ask the child to hold his hands up and then crouch down. Trim excess off to make the front mobile and as comfortable as possible. Keep excess cardboard.

Step 6

Take the rear box component and measure the sides 4 inches from the top, then slice with the box cutters, leaving a top panel with side flaps.


Step 7

Fit the top onto the child by having him crouch down as in Step 1. Measure the box from the back of his neck to the end of his buttocks.

Step 8

Measure another set of cardboard as an "L" for the door of the truck cabin. This should cover the width of the subject's arm with the tail of the "L" blending toward the legs. Cut and paint red with blue flames. When dry, add an Autobot symbol in silver to the door.


Step 9

Trim the front of the top panel off so that the back flaps sit against the buttocks. Keep any excess cardboard.

Step 10

Paint the 2-litter bottle and tennis ball cans silver. Paint the front and side panel red (front and back).



Step 11

Glue the 2-liter bottle to the right arm "L" tail so it sits horizontally as the subject is crouched down. This is the metal exhaust pipe of the truck when in truck mode or the gun when in robot mode. Glue clear plastic in as the windshield.

Step 12

Measure a piece of cardboard the width of the top back panel and 4 inches long. Cut this out and paint it red (front and back).


Step 13

Measure the length from the knee to toe on the subject and cut two 2-sided panel from the bottom of the remaining box. Essentially use the fold of the box to be the panel joint. The width should adequately cover the leg of the subject on the side and top (back of the legs). Paint these blue on both sides.


Step 14

Glue the panel from Step 13 to the back of the T-shirt. Use the glue in the area near the middle of the back, allowing the top to stick up but keeping the T-shirt moving freely underneath near the shoulders. Allow to cool.

Step 15

Paint flames on the panel in Step 15 as well as the leg panels with the opposite color paint and use yellow to highlight the edges.

Step 16

Glue the tennis ball cans to the panel from Step 15 approximately 3 inches from the top extending over the edge with the open parts of the can over the edge. These are the smoke stacks.

Step 17

Glue the leg panels to the sweat pants. Be careful not to let the pant legs twist. It is important to get the glue on the back of the leg and the outside sides to attach the leg panels.

Step 18

Cut out cardboard tires (4) and glue on the back sides leg panels. There should be two on each leg.

Step 19

Cut two strips of elastic band measuring 2 feet each. Glue each one to the interior front panel of the costume.

Step 20

Place T-shirt (with back panel) on the subject and measure the front panel on them with the elastic. Cross the elastic over his shoulder behind their neck, like suspenders. Mark the length of elastic band needed to attach to the inside back panel above the glue.

Step 21

Remove the T-shirt and cut the elastic bands, gluing them to the point between the T-shirt and inner top panel. Allow to dry.

Step 22

Tape the panel with the tennis ball cans to the back top panel. Cardboard may needed to reinforce this panel to sit up away from the child's body. Touch up paint may be needed after this step.


This is a basic Autobot costume. You can add glow sticks to the cans and bottles to give them a great cool "energon" glow during the night. You can also customize the front and doors with windows, grills and other details as you desire, essentially adding other box parts on.


Kids will love this costume, but will have difficulty moving in it. Proper fitting will help keep them able to run around while being safe.


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