The idea of this project is to be able to make a custom body to put over a tiny r/c car. This way, all the super tech-know-stuff is already taken care of, and we get to go right on to the art. The car used here is the Mini Coke Can Car. The car is charged from 2 AA batteries in the transmitter so no additional electronics are needed. Materials for our custom body must be lightweight, so we can't really 3-D print too much of it as weight quickly exceeds what the poor little car can carry, so art board foam is employed. As always, we need tools and supplies.

Supplies

Coke Can R/C Car: Comes with transmitter and car in a cool little can shaped storage kit, just add 2 AA batteries

Glue Sticks: Dollar Tree or where ever.

Foam Board: A display foam board with paper on front and back. Most places it's next to the poster board.

Paint: Water based like Hobby Lobby or Walmart sells.

Clear Spray Paint: Optional overcoat for weathering "Frosted Glass" or "Clear Matt" protects weathering effects.

3-D Printer: The "jet engines" and flat plate frame that screws onto the car are printed. I used Ender 3 pro.

Water Bottle: Windscreen is cut from an empty water bottle.

Spackle: Lightweight spackle, I used Dap Vinyl spackle from Lowe's.

Tools include: X-Aacto knife, hot glue gun, small hobby paintbrush, sandpaper, ruler, sharpie red and black, small phillips screwdriver, drill and bits, AA batteries, bamboo skewers, chalk pastels for weathering.

Step 1: The Car Modification

Take the car out of the can and charge it up as in the supplied instructions. Test drive it and make sure it works. Flip it over and remove the 2 tiny screws beside each bumper area and the body should come off easily. The lights remained with the car on mine. Print out the car frame file and screw it on in place of the body. Now, the car has a flat plate on top the speeder can be glued to. Set aside the car in a safe place for now.

Step 2: Cut Out the Body

The foam sheets I got from Dollar Tree are 51x76 cm. I cut 3 parts out rough 125x54 mm rectangular. Cut the center out of 2 of the pieces as dimensioned in the pictures. I cut one with the front contour and made sure it was symmetrical. It was then traced over the other 2 and all were cut so they match. I used the glue stick and glued all 3 together. So these part should be 3 layers of foam with a cavity for the car to poke up into. I peeled the paper off the top and bottom of the assembled parts and sanded them with 120 grit sandpaper, rounding the front and sides but not the rear.

Step 3: Bamboo Skewers

Using a skewer, I pushed through the side of the assembly at the middle layer of foam about 16mm from the back end. This needs to be straight . Mine was a little off but I made the hole on one side bigger and fixed it straight with a dab of hot glue. The glue is usually too hot for foam, so I put some out on a scrap piece of foam first and then apply it with another skewer after it cools for a moment. The skewer for the fin is about 34 mm long. I piloted the hole for the fin with a sharp skewer entering at the top about 4 mm from the rear and at about a 45 degree angle, aiming to intersect the other skewer. Then, I glued in place the 35mm skewer in that hole. Looking from the rear, I check for straightness.

Step 4: Engines and Wings

I printed 3 jet engines from a design I made in Tinkercad. I set the printer to print with raft. They came out ok so next was to drill the holes for them to mount on the skewers. The one for the fin has to be drilled at the same angle as the skewer on the body. I drilled the hole a bit bigger and used hot melt glue to place it which allowed me to hold it straight until it was cool. I did the same for the other 2 engines except they are drilled at 90 degrees. With the motors on, it is starting to look cool. I then peeled the paper from some pieces of the foam, cut them to fit between the engines and body, then hot glued them in.

Step 5: Spackle....? Yes!

I used a lightweight spackle, the kind for patching minor dings in walls. This smoothed out and contoured the wings, fin and any severe dents in the body. It is water based so ok for foam. I let it dry for a few hours. It sands easily. I used 120 grit sandpaper wrapped around a sharpie to get the nice contour shapes. At this point, I inspected the whole frame for any bumps or holes to spackle over.

Step 6: Paint and Weathering

I used a water based paint from Hobby Lobby "apple barrel" brown. A drop of red was added to it which made it a little bit too pink, but it darkened when it dried. For details, like panel lines and the "seating area", I used sharpies and a ruler to draw them on and filled the cabin area in with a giant sharpie. For the lines on the side, I just put the pen on the table and pulled the model along the pen. I adjusted the height by adding stuff under the pen.

Another detail item I love to do is add dirt and wear. With the 120 grit sandpaper, lightly sand over the engines and the slight printer artifacts show through. Then, I made use of the chalk pastels by scraping different earthy colors with the knife onto a paper. A dry brush is used to pick up each color and smear it around the model where I think it would be dirty or dusty. Some areas, I pushed it in with a paper towel as it may not be dark enough. To make the pastels permanent, a coat of clear spray paint "frosted glass" was used to seal it and make all surfaces "dull" like sun faded paint. Since the foam was painted with the water based paint, the spray paint won't attack it.

Step 7: Windshield

At this point I almost have a speeder. The windshield is next. On mine, it is simply the top of a discarded water bottle. I cut a few paper patterns, folding them in the middle to make them symmetrical and trimming until I got a shape that roughly worked. Paper is flat, but I wanted the rounded shape so the area near the top of the water bottle seemed right. I taped it on the bottle and drew around it with a sharpie. I was a little too high on the bottle as the neck area is thicker and harder to cut, but it came out ok. I think a good way to glue the windshield on would be to glue a curve onto a scrap board or box, set the bottom of the windshield on it to pick up the glue, then place it on the car, following the edge of the cabin area. Windshield on! Looks like a speeder now.

Step 8: Final Assembly

I let the glue gun heat up but then unplugged it to get it to cool a little so the hot melt wouldn't destroy my foam and glued the car adapter onto the bottom of the model. The cavity area is ample so no parts interfere with the car's workings. Just 2 screws hold the car in, so it can be removed anytime. You can barely see the car under the model so it is a cool effect. I remember when I first saw the speeder on the big screen.

Step 9: Reflections

It was fun making a model from scratch. Seeing the speeder actually drive on the table was fun too. Even with just a few plastic parts, the speeder is a bit heavy for the car to pull. To make it better, the engines could be turned from balsa on a drill to save weight. We learn from the first one so the next one will be better.

This might even make a nice Christmas tree ornament.