Cardboard Mario Kart Costume

In 2018 a group at work decided to participate in a Halloween costume contest. We settled on Mario Kart as a theme and I set about to design a kart that could be made from cardboard. We needed to make 4 of them (plus 2 for my kids) so I tried to come up with a design that I thought looked good but wasn't too complicated to make. I was pretty happy with the final result so I am sharing the design here along with instructions and photos.

Remember, have fun. These instructions cover what I did but I encourage you to be creative.

(Don't get concerned if it looks like my kart is a lot smaller than yours. For the purposes of these instructions, I built a half-sized kart.)

Tools:

• Printer
• Metal straight edge or ruler
• Utility knife
• X-Acto knife
• Sharpie marker
• Pencil
• Pliers
• Scissors
• Small clamps (nice to have)
• Self healing cutting mat (nice to have)

• Cardboard (and lots of it)
• Wood glue (I used Gorilla brand Wood Glue)
• 3M Extreme Hold Duct Tape
• Metal wire coat hanger
• Drinking straws
• Card stock that your printer can handle
• Clear tape (I used clear packing tape)
• Painter's tape
• Paint brushes
• Acrylic or spray paint
• Black
• Yellow (I used Krylon ColorMaster Bauhaus Gold - Gloss)
• plus colors of your choice. I used:
• White (Krylon ColorMaster White - Gloss)
• Red (Krylon Foil Metallic Red)
• Blue (Krylon Foil Metallic Blue)

There are a number of PDF patterns to print. When you print them from Adobe Acrobat, be sure to print them at "Actual size". Your printer might not print all the way to the edge of the paper but that won't matter. I suggest printing the patterns to card stock to make it easier to trace.

Many of the patterns span multiple pages. You should be able to tape the pages of them together without having to trim the paper. I like to use clear packing tape, but you can certainly use any clear tape.

Assuming you are using cardboard boxes, look for the seam. I suggest separating the box at the seam in order to get the most usable area from the box.

The patterns provided here assume that your corrugated cardboard is 1/8 of an inch thick.

Also, pay attention to the "grain" of the cardboard. By this, I mean the orientation of the corrugation in the center of the cardboard. When layering cardboard, it will be strongest when one layer is rotated 90 degrees from the other layer. I use this method for the steering wheel to give it strength.

Print out the multi-page pattern for the body. My cardboard wasn't large enough for the full body so I cut it in 2 sections (left & right)

Start the folding process with the side panels. Put the nicer side of the cardboard on the floor. Now, place a metal straight edge along the line where the side panel will need to be folded. Refer to the pattern to look for the dotted line.

Press the edge into the cardboard to establish the crease and then fold the side panel upward.

With the nicer side of the cardboard on the floor. Use a metal straight edge to put along the edge where the rear bumper needs to be folded. Press the edge into the cardboard to make a crease and then bend it upward. Now do the same for the triangular part at the end of the bumper.

The triangular tab will be used to glue the bumper into place. Do a test fit to make sure the bumper can be folded into place. Try to get the top and bottom edges of the rear bumper to line up with the top and bottom edges of the side panel. When things look good, apply glue to the triangular tab and then glue it to the inside of the side panel.

For the curved sides of the front bumper, use the metal straight edge technique to apply creases every 1/4" or so into the cardboard. Start at the point where the bumper separates from the top of the body and then continue out to the far end of the bumper. Apply these creases to the left and right sides of the bumper.

Once the creases have been made, bend the bumper around the side and press it along the side panel to make sure it has the right shape. Once it seems to have the right amount of curve, apply glue to the 2 small tabs. Also apply some glue to the front inside edge of the side panel. About an inch wide section will do.

Now, bend the edge of the front bumper around the curve, touching it to the 2 small tabs. Put the end of the bumper on the inside of the side panel where you applied the glue. Make sure that the curve of the front bumper is still allowing it to rest against the 2 small tabs.

The front bumper will probably stick down a bit further than the side panel but this will be hidden by the front wheel.

If you were not able to cut the kart body out of a single piece of cardboard, now is the time to attached the 2 halves together. Take a 4"x4" square and then glue it to the underside of the 2 pieces, attaching them together.

Take one of the 2" x 4" tabs and then follow the same process as above to connect the halves of the front bumper together.

Go through the same process to join the other end of the body.

Like we did on the body, use a metal straight edge to put the creases indicated on the pattern onto the cardboard of the seat. There are tabs for you to apply glue to as you can see in the photos. When you fold the seat together, those tabs will keep it closed. Try to get bottom of the side panel to meet up with the back panel of the seat.

Now it's time to make a slot for the seat to attach to the body. I went with the angled side of the seat as being toward the back of the kart but it can work either way.

Center the seat and place one tab of the seat against the back edge of the hole for the driver. This tab will fold under the kart body. For the other tab, fold it toward the back of the kart and make sure the seat is pressed down on the kart. Use a pencil to mark the corner where the tab of the seat meets the back edge of the seat. We will be making a 1/8" slot in the body for that tab to be inserted into.

Now that you have the marks, remove the seat. Draw a line connecting the 2 marks. Now make a matching line 1/8" inch closer to the center of the kart. Cut this slot out with an X-Acto or utility knife. Do a test fit of the seat to make sure the rear tab of the seat fits in the slot.

Remove the seat. Don't glue the seat into place at this point and just set it aside.

Trace the pattern for the front console onto cardboard and then cut it out.

Now it is time to make the folds. Refer to the pattern to see where the folds need to be made. I pressed the side of a metal straight edge into the cardboard along the line where I wanted the fold to be. Bend the cardboard along the creases to match the pattern.

Apply glue to the tab indicated, and then fold it under the rectangular side. Do the same to the tab on the opposite side.

Flair the tabs of the front console outward. Now place the front console centered on the front portion of the body.

Get it centered as best you can and then draw pencil marks to indicate where the tabs meet the base of the front console.

The cardboard tab is probably 1/8" thick. Make pencil marks 1/8" away from your marks toward the center.We are making a 1/8" slot for each of the tabs.

Once the marks for the slot are drawn, cut out that rectangular slot.

You should now be able to insert the tabs from the console and move it into place. Try to get the front console positioned just right. It is important to get it centered and try to make it flush with the front of the kart.

On the underside of the kart, find the tabs and then bend them outward. You should now glue these to the underside of the body after double checking the fit of the console.

Take the lower part of the steering wheel (with the cross) and the upper part (just a circle) and layer them. Pay close attention to the grain of the corrugation by looking at the edges of the pieces. Line up the corrugations to be the same and then rotate the top later by a quarter turn so that its grain goes against the grain of the lower part. You will want to glue the pieces together in this orientation. It will make the part stronger.

Cut the sides for the front and back wheels. The inner side of the wheel has the slot for the mounting tabs.

Cut out the wheel mounting tabs. You will use 2 tabs per wheel.

Hold 2 tabs together and slide the pair so half of the length is sticking out from each side of the inner wheel side.

On one side of the part, fold the tabs outward. Glue those tabs to the surface of the cardboard.

Now, fold the tabs radiating around the edge of the circle toward the side where the mounting tabs are glued.

On the other circle, fold all of the radiating tabs to one side of the circle.

Prepare the parts for all 4 wheels.

When orienting the cardboard for the wheel treads, try to get the grain of the cardboard to go across the the length of the tread. This will make it easier to curve them.

You will need a total of 4 treads. For the front, cut two rectangles of 3 inches by 29 inches. For the rear, cut two rectangles of 3 inches by 35 inches. This will give you a little extra length than you will actually need.

Press the metal straight edge on the surface of the tread parallel to the grain. Fold the cardboard upward in order to make a crease. Now slide the straight edge over about 1/8 inch and make another crease. Keep doing this down the length of the tread.

When you are done, you should see the cardboard adopt a curved shape.

Grab an inner and outer circle for one of the wheels as well as the appropriate tread.

Start by gluing one tab from each of the wheel sides to the tread. Try to get the edge of the tread to line up with the outer surface of each wheel side.

Once the glue has dried and the parts are secured, continue to glue half of the remaining tabs on each side and attach the tread.

After the tread is glued around half of the wheel, apply glue to the rest of the tabs and attach the tread. When you get toward the end, trim the end of the tread to make it meet up properly. When you have the length right, apply a little glue across the edge of the tread end. Worst case, if the tread comes up a bit short, you can cut a small piece to fill the gap an glue it in place. It will all be painted black anyway.

Complete this process for each of the wheels.

Gather up the following items:

• Metal hanger
• Straws
• 4 x Cardboard strips (6" x 2")
• Sharpie
• Scissors or utility knife
• Pliers

Take a cardboard strip and fold it in half.

Cut a 2 inch section of the plastic straw.

Straighten the metal coat hanger. You will need to cut off a 5 inch section.

Use the Sharpie to put marks at 1", then 1/2", then 2", then 1/2", then 1". This is where the bends will need to be.

I suggest starting with making right angles on either side of the 2" section. After that, bend each of the 1" sections together to close the rectangle. For now, don't close the rectangle completely.

Now, take a 2" section of straw and you will need to put the two 1" ends of the coat hanger through it and then close the rectangle. It's okay if the straw gets a lot of creases in it.

Now take your folded cardboard strip and put it through the metal rectangle so that the straw is in the fold of the cardboard.

With the cardboard folded, make sure the straw is all the way in the fold of the cardboard. At this point, you can glue the cardboard sides together.

You will need to make 4 of these.

I REALLY like the 3M Extreme Hold Duct Tape for this project because it looks really good for shoulder straps and it is also very strong.

To figure out the length for the shoulder harness straps, I cut strips of paper and taped them together. I then used these as a proxy for shoulder straps and put them over the driver's shoulders to see how long they should be. As a rough guide, you can probably take the length from the driver's waist to their shoulder and double it.

Once you have the desired length of the straps, add 6 inches (3 inches on each end) to account for the part that will attach to the brackets. Cut 2 strips of the tape to this length. Lay it sticky side up on the mat.

Take 1 of the brackets and loop the tape through the metal loop. Move it to 3 inches from the end of the tape. Fold the tape over and adhere it to itself. The tape is very sticky so try to get it aligned right the first time.

After you get a bracket attached to each side of a strap, cut additional strips of tape and apply them to the exposed adhesive part of the straps. You don't need to worry about the lengths being precise but do try to get the sides to line up so that there isn't any adhesive exposed.

Paint the seat, steering wheel, and all of the wheels black. You won't need to paint the tabs that are sticking out of the wheels but do paint both sides of the wheels.

As mentioned before, I kept these parts separate from the body to make the painting easier.

To get nice clean lines on the wheel rims, I printed the attached patterns on card stock and cut them out. I just painted them with yellow paint and set them aside to be attached later. The rims on the rear wheels are a bit larger than the ones on the front.

For the kart body, I painted it all white as a base coat. I then added red and blue accent colors. You can see what I did for my Mario kart in the attached PDF. This is your kart though. Try to replicate the color scheme of your favorite character or just be creative.

When you go to paint the front console, try to refer to the Steering Wheel Mounting Guide to see where the steering wheel will be touching the front console. It will be best if you can leave some exposed cardboard in order to provide a better bond with the wood glue later.

Now that everything is painted, it's time to get out the glue again. You can glue the yellow rims onto the wheels. Remember, the smaller rims go on the smaller wheels. There are rim mounting guides here in case you want some help in getting them centered.

When I initially built the karts, I used spray contact cement but later I have also just used a thin layer of the wood glue.

Take the tab of the angled side of the seat and slide it into the slot in the body that we made earlier. Make sure the seat is flush with the body.

Flip body over and glue down the tabs of the seat.

Gather up your wheels. We will be putting the tabs you made earlier to use.

For reference, the tab is closer to the top of the wheel than the bottom. This is true for the front and the rear wheels. The smaller wheels are for the front and the larger ones are for the rear.

Pinch the tabs together and slide them through the mounting slot on the side panel of the body. Make sure the wheel is flush with the side panel. When it seems good, fold the tabs apart and glue them down to the inside of the body.

Complete this step for each of the wheels.

Looking at the underside of the kart, start with the area where the seat attaches to the body. Glue a shoulder harness bracket next to the tab of the seat. The metal part of the bracket should be just extending past the edge of the body.

Now take the bracket on the other end of that shoulder harness and cross it over to the opposite side of the kart to underside of the front console. I have a piece of cardboard attaching the left and right sides of the body so I glued the brackets next to it.

Make sure that the shoulder harness straps are not twisted.

Attach the other shoulder harness in a similar manner.

When you go to wear the kart when you are done, the straps will cross along your back. This should help a little to keep the straps from falling off of your shoulders.

For the steering wheel, you will be gluing the side with the cross to the kart. There is a mounting guide here in case you want some help.

For the emblem on the front of the kart, I used my Silhouette Cameo to make adhesive vinyl stickers. You could also just print out an emblem and glue it on. There are many resources on the internet for the various emblems. Just print it out in a 6 inch circle and cut it out.

Attached here is a mounting guide that you can use to get it positioned correctly on the front console.

That's it! The kart is done. Just a reminder, when putting on a kart, have the shoulder harness straps cross over behind you.

Have fun!