How to add weight to a Racer Pinewood Derby Car
The heavier your pinewood derby car, the faster it will go. Most race rules limit the weight to 5 oz so you want your car as close to the limit as possible. The Racer block will need about 2.5 oz of additional weight to bring it up to the 5 oz limit.
You shouldinstall the weights in your car before you paint it.
Before adding the weights to your car, put the car block, wheels, axles and any other accessories that you will be adding to your car on a scale. Then add the weights until the total is 5 oz. (paint will add very little to the weight of your car).
When your car is complete, weigh it again. If it is over 5 oz, drill a few holes in the bottom of the block about an inch behind the front axle to remove some wood.
Below are several suggestions for adding weights to your pinewood derby car.
Lead Wire Weights
Lead is inexpensive, dense and is easy to work with but lead is toxic. Always use gloves when working with lead and make sure that none of the lead is exposed after you install it in the block.
When weighing the car and weights, use three weights that are approximately the same length. You can cut the weights with a hack saw, coping sawor wire cutters.
You will need:
- One set of Lead Wire Weights
- Drill and 5/16" drill bit
- Wood putty
- Sandpaper
- Hack saw, coping sawor wire cutters
- Clamp the car block on a flat surface.
- Using a 5/16" drill bit, drill three equally spaced holes into the back of the block at a slight up angle so that you drill above the rear axle slot. The depth of the holes should be slightly deeper than the length of the weights.
- Remove the clamp from the block.
- Insert the weights in the holes. The end of each weight should be at least 1/8" into the end of the block. This will leave room for the wood putty. Drill the holes deeper if needed.
- Weigh the block, wheels, axles and weights again. Adjust the amount of weight if needed for 5 oz.
- Seal the weight holes with the wood putty. Allow to dry in a warm place for 12 hours.
- Sand the wood putty until smooth and flush with the car block.
You can now paint your car and add the wheels and axles.
If the completed car is less than 5 oz. drill one or more shallow holes in the bottom of the car behind the rear axle and insert some of the leftover lead weight in the holes. Don't drill so deep that you drill into the other weights. Seal with wood putty.
Tungsten Weights
Tungsten is very dense but it is more expensive than the other weights. The density gives you a speed advantage because more of the weight can be placed farther back on the car.
You can use a combination of cylinders and a flat weight for optimum results.
You will need:
- Four Tungsten Cylinders
- One Tungsten Plate
- One Fine Tune Cylinder
- Drill and 3/8" drill bit
- Wood putty
- Sandpaper
- Screw driver
- Clamp the block to a flat surface.
- Using a 3/8" drill bit, drill two holes into the back of the block at a slight angle so that you do not drill into the axle slot. The depth of the holes should be deep enough to hold the cylinders.
- Remove the clamp from the block.
- Insert the weights in the holes. The end of the weights should be at least 1/8" into the end of the block. This will leave room for the wood putty. Drill the holes deeper if needed.
- Weigh the block, wheels, axles and weights again (don't forget the flat weight). Adjust the amount of weight if needed with the Fine Tune Cylinder.The Fine Tune Cylinder can be cut with a scissors or knife.
- Fill the weight holes with the wood putty. Allow to dry in a warm place for 12 hours.
- Sand the wood putty until smooth and flush with the car block.
- Paint your car and add the wheels and axles.
When the paint has dried and the wheels are on the car,attach the flat weight to the bottom of the block behind the rear axle slot using the supplied screw.
Tungsten Canopy
The Tungsten Canopy is attached to the top of the pinewood derby car. The canopy has a stud to help keep it in place. A 3/8" hole will be drilled in the top of the block for the stud.A Fine Tune weight can be added to bring your car up to the 5 oz limit.
You will need:
- One Tungsten Canopy
- One Fine Tune Cylinder
- Drill and 3/8" drill bit.
- Super Glue or Epoxy.
1. Mark a spot on the center of the block and 5/8inch from the back of the block. This is where the hole for the canopy stud will be drilled.
2. Drill a 3/8" hole perpendicular to the slope of the top of the car at the location where you marked. Use a credit card or business card to align the angle of the drill. Place one edge of the card on the center line. The drill should line up with the other edge of the card. Drill the hole 1/2" deep. Test fit the canopy in the drilled hole. The bottom of the canopy should be flush with the top of the car.
3. Remove the canopy and paint your car. Let the paint dry.
4. Glue the canopy to the top of the car with super glue or epoxy.
5. Place the block, wheels and axles on a scale. If the weight is over 5 oz, drill holes in the bottom of the block between the two axle slots until the weight is 5 oz.If the weight is under 5 oz. drill one or more holes in the bottom of the car just in front of the rear axle and insert enough of the Fine Tune weight to bring your car up to 5oz. Glue the weight in the hole.
6. Add the wheels and axles to your pinewood derby car.
