Steps to Building a Pinewood Derby Car 
 

Step 1:  Decide on the design. Using TEMPLATES will make it easier to come up with a basic design for the body of the car.   

Step 2:  Cut a shape out of the block of wood using a COPING SAW.  If available, a ROTARY TOOL with a sanding drum attachment can be used to add contour and curves to the body of the car. 

Step 3:  Taking a nail and the wheel, slide the nail into the groove cut into the bottom of the car.   If the nail cannot be slid into the groove, expand the groove by gently shaving material from either side using a SHARP HOBBY KNIFE. 

Step 4:  Using a SHARP HOBBY KNIFE or MOTOR TOOL, remove enough wood from the bottom of the car in order to accommodate installation of WEIGHT.  Preferably, center the weight between the two axle grooves located on the bottom of the car.   

Step 5:  Sand the car using 180 GRIT, 400 GRIT and 600 GRITT SANDPAPER in the order described.  After sanding the vehicle apply SANDING SEALER and remove the SANDING SEALER after drying with 600 grit sandpaper. 

Step 6:  Painting the car.  Using a 12 inch to 16 inch long x 5 x 8 inch deep x 8 to 10 inch high cardboard box as a paint booth, along with saw horses made from cardboard, place the car on the saw horses inside the box.  Apply finishing materials in the following order:  PRIMER, COLOR COAT AND GLOSS COAT.   

PRIMER:  Apply 2 coats of primer waiting 20 minutes between each coat. Let the car dry for 24 hours. 

COLOR COAT:  Apply at a minimum 2 coats of dark colors as well as a minimum of 3 coats of light colors.  Wait 20 minutes between each coat.  Let the car dry 24 hours after application of color coat. 

DECALS/GLOSS COAT:  After the car is dry for at least 24 hours, decals may be applied and gloss coat sprayed AFTER decals have been applied to the car.  Apply a minimum of 3 coats gloss coat, waiting 20 minutes between each coat, with a maximum of 3 coats applied in a 24 hour period.  Gloss coat adds depth and shine to the finish and seals the decals to the painted surface.  The more gloss coat applied, the shinier and deeper the color of the car will be.  If time allows, apply gloss coat in the manner described over a three day period.  

The factors influencing the speed of a Pinewood Derby Car in order of importance are:

  • Alignment of the wheels
  • Level of friction associated with the wheels turning on their axles
  • Level of friction as wheel rolls down wooden track
  • Overall weight of the car which cannot exceed 5 ounces. 

 

Steps to Achieving Maximum Speed:  Use of Materials in Speed Kit 

Step 7:  Insert one of the nails into a ROTARY TOOL or hand drill.  Motor tools achieve RPM levels of 35,000 to 37,000 versus hand drills that generate RPM levels of 700 to 1000 RPM’s. Motor Tools provide the best method of polishing metal surfaces given the high level of RPM’s generated. 

Step 8:  Using a set of SMALL DIAMOND NEEDLE FILES, file off the casting mark located under the head of the nail being careful to remove all excess casting material up to the shaft of the nail.   

Step 9:  In a small cup, mix POLISHING PUMICE with water to the consistency of oatmeal.  Cut 600 grit wet/dry sandpaper into ¼ inch wide strips.  Apply pumice and water mixture to sandpaper and polish the shaft of the nail from the surface of the nail head down approximately ¼ of an inch.   (This area is where the wheel will ride on the nail/axle and as a result need to be cleaned and polished to minimize friction.)  After polishing the surface, mix a small amount of silver polish and toothpaste together and apply to a ¼ inch wide strip of cloth.  Now you will polish the area indicated above. 

NOTE: Increasing the sand paper grit level used to polish the nail shaft will produce incrementally lower levels of friction as the nail spins around the nail shaft.  Grit levels can go as high as 12,000 grit which produce a much smoother surface.  When using higher grit paper, increase the levels accordingly:   600 to 800 to 1000 to 1200.  After 1200, grit levels can be increased in increments of 2,000 to 3,000 up to the level of 12,000.  It is recommended that the nail shaft be “cleaned” with the silver polish and toothpaste mixture after each increase in grit level. 

Step 10:  Using a WHEEL TURNING MANDREL affixed to a hand drill, sand the tread surface of the wheel smooth using a mid range grit sand paper of 400 to 600 grit. 

Step 11:  Take a polished nail and sanded wheel and insert the nail through the wheel hub.  Apply graphite to the area where the nail shaft comes through the wheel hub and spin the wheel.  Apply graphite to the area where the nail head rides against the wheel and spin the wheel.  The objective is to lubricate the areas where the wheel and nail meet.  Repeat the process on all four nails and wheels.  You cannot apply too much graphite.  The more the better!  Repeat the process on each nail wheel combination several times.  After completing this step, all four wheels should spin for approximately the same amount of time.  This amounts to approximately 25 to 35 seconds.  Using higher grit sand paper, as mentioned above, will increase “spin time”.  As a result, the car will gain speed faster, maintain it longer and bleed off speed slower. 

Step 12:  At this point the car has been cut, sanded, painted and decals have been applied.  The wheels and nails have been polished and sanded.  Do not assemble the components until they are weighed and the total weight of the components have been determined.  Once you have determined the total weight of the components, add enough auxiliary weight to the scale to bring the total gross vehicle weight to 4.9 ounces. 

Step 13:  Affix the auxiliary weight to the car in the space cut.  (See Step 4 above).  After installing the weight, slide each wheel and nail combination into the grooves located on the bottom of the car.  After installing the wheels, align the wheels utilizing a Wheel Alignment Tool to set the distance of each wheel hub from the body of the car and remove all camber and toeing in or out from the wheel alignment.  Once aligned, glue the nails in place utilizing a mid grade fast drying (5 to 15 second) C. A. GLUE. 

RIDERS HOBBY SHOP
21800 Town Center Plaza, #236
Sterling, VA  20164
(703) 430-2202

www.ridershobbysterlingvirginia.com