This was done with a 1 week deadline, keeping in mind all standard pinewood derby rules and dimensions. It lacks most details that I would have liked to add (sponsors, inlet curves, Niki Lauda signature, etc), but ran out of time.
I used a dremel multi-tool kit for most of the body shaping.
Tools & Parts:
- Derby car kit (wood block base, axles, wheels)
- x-acto knife
Body shaping phase:
- Coping saw
- Dremel with wood cutting and sanding attachments
- Sandpaper (60, 120, and 240 grit)
- Gray spray primer
- "Banner red" spray paint
- Modeling paint (Green, yellow, white, black... probably should have touched up with red, but ran out of time)
- Paint brushes
Step 1: Layout Phase
I started with a few drawings until deciding upon the '76 ferrari. Getting the dimensions appropriate for a pinewood derby car was the most difficult part, but it was mostly done by proportions.
Trace out the wood block on a piece of paper, first looking top-down, then looking right to left. Keep them in line with each other. It will save a lot of time with the drawing. Be sure to include lines for wheel position. I recommend making a copy of this as a template if you plan on trying a few things out. Then begin to draw out your model. Start with rough, sharp lines before adding curves and details. This will let you know where to make major cuts before sanding. For some help, I included the layout.
With the drawing complete, cut out the layouts with an x-acto knife (carefully). Tape the views to your pinewood block. I taped my top view on the bottom of the car, knowing that the bottom would stay flat and not be touched by the dremel.
Step 2: Body Shaping
Using a coping saw, or a more useful tool if you have it, take out the large portions. It's easiest to start with the side view and cut out the outer profile, leaving room for mistakes. This allowes you to sand details later.
Move to the top profile, cutting out the two large gaps between the front wing and wheel hubs. After that, I used the dremel to make some very rough cuts to begin work on the car body housing.
Step 3: Sanding
Then, with a rough grit sandpaper (60), sand to shape most of the body, moving the sandpaper with the grain. Get the overall shape looking how you want it at this point
With a finer grit sandpaper (120), sand out the scars and scratches caused by the rough sandpaper. This takes more time than the last phase.
With a more fine sandpaper (240+, DRY!) sand the body to be smooth.
Hold the car up to the light and look along the edge. Are there imperfections? If so, use the necessary grit sandpaper to smooth them out, then polish it off with a fine sandpaper.
At this point, I was on day 4 of the project, so I left some imperfections on the body and moved ahead to painting. If you're not rushed, take your time with the sanding. It will really pay off in the end. There are some noticeable dents and rough patches on my final paint job that resulted from a hasty sanding phase.
(pic is from somewhere in the middle of the sanding phase)
Step 4: Painting
This will highlight imperfections of your car. Sand them out, and lightly sand the rest of the car to allow for another coat of primer.
Add another coat of primer and let it dry. If there are still imperfections, lightly sand them out. If you are still unhappy with the look, give the whole car a good sanding to remove some of the primer, then repeat the priming process.
With the primer dry, add the first layer of base paint. I chose "Banner Red" for the ferrari look. To save time, I taped off the front wing with paint tape and just used the primer color for the wing. I don't recommend this.
The first layer of paint is rough and unsightly. Add another layer to get a nice glossy shine. Had I put more time into sanding, this would have looked even better.
With the last coat dry, start with the detail paint. Using paint tape is your friend for straight lines. Most of the white was achieved with this.
Again, I ran out of time to do the details (I was literally painting an hour before the race), so leave plenty of time for this phase.
The rear wing / spoiler was an afterthought for me. I had actually forgotten about it until the last day of the build, so I quickly made a shape out of scrap with my dremel, sanded it to fit how I wanted, then coated it with primer. To attach, I sanded a small region on the car's base, then used wood glue.
Step 5: Finishing Touches
For the wheels, spread a small amount of white paint thinly across a piece of paper. Then, lightly dip each wheel into the paint (like a stamp) so that the letters get highlighted with white, but the tires stay black. You may even paint the hubs to look like metal.
As an option, you can buy decals at a hobby store, or get them from a race car model. This would add a lot of realism to the car. Or, you could paint them...(this is way out of my league, as far as painting goes)
For an extra, metallic-looking shine, coat the entire car with a clear coat.
Attach the wheels to meet pinewood specifications, and that's it!
Making your car fast!
Here are a few tips to help boost the speed of your car:
- Make absolutely sure the two slots for the axles/wheels are perpendicular to the car's body, and parallel to each other. If not, the car will pull to one side or the other and grind against the slot (causing a lot of friction to slow the car down). If this is a problem, check with your rules and see if you can drill a new slot for the axles.
- If you have a 5oz weight limit, you want to be as close to this limit as possible, without going over. A heavy car doesn't guarantee a fast car, but it will certainly boost your time. Add weights toward the back of the car to achieve this (drill holes underneath and attach tungsten weights, or get creative with nuts, coins, or whatever you have around). You want the center of gravity to be about an inch forward from the rear wheels. If it's too far forward, your car won't gain the benefits of the added weight. If the c.g. is too far back, you will lose stability, which causes too much friction.
- If your rules allow it, use a dry, graphite-based lube. Squeeze it in to the wheel/axle hole with the axle attached, then give it a spin. Repeat this one or two more times. Notice how long the wheel spinned before and after the lube.
- There are plenty of other tips for modifying your axles and wheels, but these are usually banned in derby races. Feel free to ask for tips if you'd like.
That's it. Hope you enjoyed my tutorial! Feel free to ask whatever questions you may have along the way. This is my first instructable, so I'm well open to constructive feedback. Also, if you do attempt this, or something similar, I'd love to hear your story about it!