How to add weight to a Wedge Pinewood Derby Car
How to add weight to a Wedge 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 Wedge 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.
Zinc Top Weight
This aerodynamic weight is 2.2 oz and can be easily attached to the top of your car with the supplied screws
You will need:
- Aerodynamic Weight
- Bottom Weight
- Glue
- Screwdriver
Sand and paint your block but do not add the wheels.
When the paint has dried, mount the weight on the top of your car as far to the rear as possible. The weight should not extend past the rear of the car.
Glue bottom weights to the bottom of the block to bring the total weight (including wheels and axles) to 5 oz. Install some of the weight behind the rear axle and the rest in front of the axle. The weight can be broken apart with pliers. Do not install over the axle.
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.
- Place the car block upside down on a flat surface (you are placing it upside down so that the weight holes will follow the slope of the top of the block).
- Clamp the block to the surface.
- Using a 5/16" drill bit, drill three equally spaced holes straight into the back of the block, 3/8" from the top of the block. 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 pinewood derby 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.
Cut the Fine Tune weight to bring your car up to the 5 oz limit.
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 pinewood derby block to a flat surface.
- Using a 3/8" drill bit, drill two holes straight into the back of the block high enough so that you do not drill into the axle slot. The depth of the holes should be 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. The fine tune weight can also go in these holes or you can drill a hole in the bottom of the block in front of the rear axle for this weight.
- Weigh the block, wheels, axles and weights again (don't forget the flat weight). Adjust the amount of Fine Tune weight if needed.
- 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, it is time to install the flat weight. Place a pencil under and across the car one inch in front of the rear axle. This is where the car should balance. Place the flat weight on the top of the car and move it forward and back until the car balances on the pencil. This is where the flat weight should be placed under the block. Attach the flat weight using the supplied screw (Some rules do not allow covering the axles slots. Check your rules before mounting the flat weight and adjust the weigh placement if required).
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. Draw a straight line with a pencil down the center of the top of the block.
2. Position the canopy on the center line near the back. Place two wheels and axles on the top of the car directly over the front axle slot.Place a pencil across the bottom off the block and one inch in front of the rear axle. Move the canopy along the center line until the car balances on the pencil. This is where you want to mount the canopy.
3. Use the pencil to mark around the canopie's stud. This iswhere the hole should be drilled to mount the canopy.
4. Drill a 3/8" hole perpendicular to the slope of the top of the car at the location where you marked for the canopy stud. 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.
5. Remove the canopy and paint your car. Let the paint dry.
6. Glue the canopy to the top of the car with super glue or epoxy.
7. 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.
8. Add the wheels and axles to your pinewood derby car.
