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I learned how to drive when I was 11 years old in my dad's 1964 Chevrolet C10 pickup truck with a manual transmission and 292 cu.in. straight 6. My brother still has the truck.

The wheels, tires, and hub caps provided are for show only. They are not legal for competition, and would probably not perform very well because of increased friction. The standard wheels that come with the Pinewood Derby kit look just fine, anyway.

Note: Fully assembled, this model exceeds the maximum length and width dimensions per the Pinewood Derby rules. However, if you leave the bumpers off, it fits.

What is a "pinewood derby car shell"?

A pinewood derby is an event created by the Boy Scouts many years ago. Each scout is given a pinewood derby kit typically consisting of a block of wood with slots for axles, 4 wheels, and 4 nails to be used as axles. The scout (and his dad, usually) will then carve the block of wood into the shape of a car, paint it and apply stickers, install the wheels on the axles, and then race it at the "derby", which involves a sloped track with a timekeeping apparatus.

An official scout derby will usually require that the parts in the kit be used for cars entered in the derby. Other organizations (including workplaces) often hold derbies, too, and some of them require the use of the parts in the box, including the block of wood.

These "pinewood derby car shells" are intended to be used with an official derby wood block, cut down to size, along with the axles and wheels included in the kit. A printable model of the shaped wood block is provided. You can either use the printed model or use it to accurately cut an official wood block down to size.

Printing and Assembly Notes

Printing

Car body: Supports are required.

Wheels: Print face up, supports will be needed.

Hub caps: Print face up, no supports.

Windshield: I was able to get good results by slicing a bit off of the top to get a nice, flat surface, and then print it upside down in vase mode, with a brim.

Everything else is pretty easy to print, no supports.

I printed all parts with a 0.4mm extruder, but you may get better results on the detailed parts (front turn signals, rear lights, hub caps) with a smaller extruder (0.2mm).

Smoothing

This car was smoothed with 3d printing resin and baby powder. You can find videos and guides online that describe the process, but here it is in a nutshell:

• Mix 1 part resin and 2-3 parts baby powder in an opaque container (so that it can be stored without hardening due to UV exposure).
• Using a paintbrush or cotton swab, spread a thin layer of the resin/baby powder mix over the body, wherever you want to smooth print lines and gaps.
• Use a UV flashlight (a cheap one--like the kind used to harden resin finger nail polish, which you can order from Amazon or buy in the pharmacy department of Walmart) to harden the resin.
• Sand the body smooth until there are no thick layers left.
• Repeat over any areas that are still rough.

Weights

You can add tungsten weights to the holes in the rear of the body. If you plan well, and use enough infill, you can maximize the weights and end up right at 5 oz.

To be honest, though, this is not going to be a fast Pinewood Derby car. In addition to the poor aerodynamics, it's quite heavy and you won't be able to add much weight behind the rear wheels, so the front/rear balance will not be ideal.

Logos and Other Details

I used white waterslide decal paper to create logos for the front grille, the side badges, and the Chevrolet logo on the tailgate. I just pulled the logos off the internet, pasted them into Word, and printed them onto the decal paper.

For the hub caps, there is a distinct surface for the bow tie and the circle around it. I used filament painting in my Bambu Studio slicer to paint the circle around the bow tie black, then printed with black and white filaments using my AMS.

I also provided a distinct surface for the whitewall tires. I used black for the main color and then painted the whitewall surface.