Pinewood derby tips 2013

PACK 77
Pinewood Derby Tips 2013
1. Pinewood Derby Resources
A couple of years ago I found a good book on Pinewood
Derby car construction and speed tuning, shown on the right.
I’ve attached some extracts on the next few pages. Note that
if you actually use this book (or other similar ones), you must
be extremely careful as most of the advanced speed tips are
not legal per our Pack rules (note that everything shown in the
extracts in this handout is OK). If you have any questions on
the rules or are planning a modification you think may be
questionable, please contact us first. We want to make sure it
is a fun day for all, and having to reject a car would ruin a
scout’s day. There are also a ton of technical resources and
car supplies on the web. If you have any questions, please
contact Eric Cutright. Also, remember to check out the Pack 77 Pinewood Derby resource web
page at: http://pack77.avenue.org/derby.html
2. Pinewood Derby Car Display Stands (now also available for Regatta boats !)
Dens 5 and 7 will likely be making
spinning car display stands (shown on the
right, Star Wars X-wing not included ) to
sell on Derby day as a Den fundraiser, cost is
only $5.00 each.
They will also likely be available in kit
form if you want to put your own together at
home or as a Den activity. I can also make
custom sizes if your car does not fit (requires
a little clearance in front of rear wheels).
Note that the stands come unpainted so
that you can paint them to match your car (or
just leave them as they are if you want, as
shown in the picture).
3. Pinewood Derby Race Day Saturday, February 2nd (bring your camera !!)
The Pinewood Derby will be held on Saturday, February 2nd at the Cale cafeteria.
Registration is from 11:00-1:00pm. No cars will be accepted after 2:00 p.m. Most folks register
their car and then come back for the race. If you have an unavoidable conflict and cannot
register your car on time, please let your Den leader know and they can do it for you. If any
modifications are required, you’ll have to either trust your leader or come in to make the
changes. The race will begin promptly at 3:00 p.m. and should end by 5:30 p.m. Finally, we
will need lots of volunteers to make the race run smoothly, so please sign up.
Eric Cutright
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Pinewood Derby Tips 2013
4. National Scout Dues
The national scouting dues are due this month and must be turned in to your Den leader
before the Pinewood Derby. The fees are $15 for a year, plus an additional $12 if you want a
subscription to Boy’s Life magazine. Make checks payable to Pack 77. Note that you must be
paid up on dues to participate in the Pinewood Derby.
5. Pinewood Derby Car Construction Workshops
For those of you who might need a little help in building your Pinewood Derby car, Eric is
planning to host two construction workshop afternoons in January (dates to be announced, but
likely 1/13, 1/20, and 1/26). I could also use some extra workshop helpers so if you enjoy
building and are interested, please let me know. I will help with the rough cutting and the boys
can sand and detail their cars, plus I'll have a bunch of random fins and parts they can use.
Please note that the Pinewood Derby car construction is meant to be a SPECIAL
scout/parent bonding experience and the helpers are at your disposal for help as needed but we
will NOT build your car for you. Ask any former Scout what their most memorable scouting
experience was, and I will bet they will say building and racing their derby cars with their mom
or dad’s help!!
The workshops will be by Den in one-hour time slot sessions and will be coordinated by
your Den leader. If you have a conflict and cannot attend with your Den, you are welcome to
attend with another Den as long as there is room (we can handle up to 10 scouts per session).
Small Dens can combine as long as there are no more than 10 scouts per session, and large Dens
can run a little longer if needed. We can also help all-comer entrants, but the Scouts in each
session will be given first priority.
Each session will start with a safety briefing and instructions for the tools we will be using.
I will personally run the saws to do the rough cutting, but scouts can use various belt sanders,
drills, and other fairly safe power and hand tools with ADULT permission and very close
ADULT supervision. Note that all Webelos must complete ALL steps WITHOUT adult help
(other than safety-related supervision), so will have to use hand saws to cut out their cars. Most
importantly, the Den leaders or a delegate will be responsible for crowd control and for helping
us in making sure that everyone is following the safety rules.
6. Derby Car Design
Derby cars were handed out at the December Pack Meeting. If you missed the meeting,
check with your den leader to get your derby car kit (Den 5 and Den 7 will work on theirs during
the January Den meetings at Eric’s house so he has all kits). The Pack provides derby car kits
for all scouts, but all racers in the all-comers race must purchase their own from the Scout Shop
(or Michael’s or hobby shops).
Eric distributed a derby car brainstorming sheet (in pdf) which you can use to sketch up
ideas so you can be “ready to roll” before starting to cut out your car. If you print it out without
any printer scaling, the body dimensions should be exactly that of the block in your kit.
Remember to NOT cut in any of the areas shaded in yellow to ensure proper wheel and track
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clearance. The sheet also includes the wheel outlines so you can better visualize your design.
The maximum width, height, and length dimensions are shown at the bottom of the sheet, but
please note that each car must pass through the official dimension checking box on race day to
qualify (similar to the 5.000 oz weighing process on the official race day scale). The permitted
dimensions are a little larger than the block itself to allow room to glue on extra parts and crazy
drivers, without interfering with the track sensors and cars in other race lanes. Remember that
you can add parts to the front, rear, sides and top as long as they don’t interfere with the wheels
or track or exceed the size limits. If you plan to attend one of the construction workshops,
remember to bring any extra parts (fins, drivers, sirens, etc.) that you want to use on your car (so
we can check your total weight), and pick up weights from Michael’s or the Scout shop. Eric
also has a bunch of random parts that scouts can use plus can make any special parts they might
want.
7. Car Weight Tips
Cars will run faster if they are at or very near to the 5 ounce limit. Note that the race day
scale is the official and final ruling on the weight. We always get a lot of questions on weights
so here is some guidance: the easiest weights to use are the screw-on under-body weights
available at the scout shop or Michael’s. These have segments which you can break off with
pliers to adjust the weight prior to the race. Just remember that the under-car weights are very
close to the under-car clearance requirements so be careful (can’t be lower than 1/8” from car
bottom).
The cheapest option is to use big washers mounted in holes under the car, which makes it
easy to adjust the weight by adding/removing washers. Mid-range choices are cylindrical alloy
tubes which you can buy at Michael’s or the Scout Shop and insert into a hole in the car. The
top-of-the-line (and most expensive) weights are tungsten alloy cylinders and spheres (see
http://www.pinewoodpro.com/pinewood-derby-tungsten-weights.htm) which run about $5 per
ounce. These are super-pricey but give the most design flexibility since they have the highest
weight per volume and are easy to stick in a hole or weight compartment in the car.
If you don’t plan to use an under-body weight, the use of a weight compartment with a
screw-on cover is highly recommended and the best location (for both speed and construction
convenience) is usually at the rear of the car, where you also have enough space to fill the
compartment with weights (BBs, washers, etc.) and then attach a wood cover (drilling templates
and covers available at the workshops). Again this makes it easy to adjust the weight by
adding/removing weights on race day.
Although it is not officially prohibited, note that we do NOT recommend the use of lead
(fishing weights, shotgun shot, etc) due to its toxic properties (and certainly please don’t try to
melt lead). If you plan to attend one of the construction workshops, please be sure to bring your
weights so that they can be incorporated into the car design.
Remember to secure all your weights so they will not fall out/off during the race.
HINT: Your car will go faster if the weights are placed as far to the rear as possible – just
make sure the rear is not so heavy that the front wheels lift off the track.
Eric Cutright
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Eric Cutright
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8. Pinewood Derby Car Painting Tips (do not put wheels on before painting !!)
The best paint to use is spray paint. The trick to a smooth finish is to use a SANDABLE primer first – I get mine from Home Depot –
Rustoleum Painter’s Touch Ultra Cover Primer (white) for about $3. You can lightly sand the 1st coat before applying the 2nd coat of primer
and then lightly sand it again before the color coat of spray paint. My favorite finish spray paint is Krylon gloss spray paint which is cheapest
at Walmart (around $3).
If you apply more than one finish color or a clear gloss coat, sometimes it will wrinkle the paint if you don’t let the first color dry
completely. Plan ahead - be sure to follow the manufacturer’s directions on letting the first coat dry fully (sometimes up to 48 hours!) before
applying a different color. Use painter’s masking tape to mask off the areas for the different finish colors (e.g. like a stripe down the middle,
etc.). To be extra safe, you can then even use another coat of primer before applying the second color.
Here are the recommended steps for painting your car:
1. If needed, sand your finished car with 150 grit sandpaper, and then vacuum and/or wipe off dust with a tack cloth.
2. Apply two coats of primer paint (a sandable spray primer or even drywall primer paint like Kilz), allow to dry 1 hour between coats
and a couple hours after the 2nd coat. You can attach a stick (with double sided tape) or paint the car up on blocks or small lids so you
don’t have to touch it.
3. Sand lightly with 320 grit sandpaper, then vacuum and/or wipe off dust with a tack cloth.
4. Apply two or more light coats of spray paint of your choice. Again, use a stick or blocks so you don’t have to touch it during
spraying. Spray paint looks the best and is easiest to do, but you can also paint with a brush if you don’t have spray paint.
Note that a cool alternative to painting is the body wraps available at the Scout Shop and at hobby shops. This is essentially a full-body
sticker (available in tons of cool graphic styles) that you apply to the car.
Eric Cutright
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9. Axle Treatment Tips (optional)
Remember that you must use the axles that came in your kit, and they must be placed in the standard axle slots in your car block (AllComers are exempt from this rule). If you want to invest the time, some axle speed tips are shown below:
Eric Cutright
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Eric Cutright
Pinewood Derby Tips 2013
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Pinewood Derby Tips 2013
10. Wheel Treatment Tips (optional)
Remember that you must use the wheels that came in your kit or official BSA colored
wheels from the Scout Shop (All-Comers are exempt from this rule). If you want to invest the
time, some wheel speed tips are shown below:
11. Have Fun !!
Remember that the main goal of the Pinewood Derby is to have fun. Please stress the
importance of good sportsmanship with your scout. It doesn’t matter who wins or loses, the idea
is for everyone to have an enjoyable and memorable race day. Good luck to all !!
Eric Cutright
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