can you use lead in a pinewood derby car

Question

VonLilah · Accepted Answer

Yes, you can use lead in a pinewood derby car, and it's a very common practice among experienced builders to add weight strategically. The key is to do it safely and within the official rules of your event, typically governed by the Boy Scouts of America or similar organizations. The primary goal is to bring the car's weight up to the maximum allowable limit—usually 5.0 ounces—to maximize momentum. The most effective strategy is to place this weight as far back in the car as possible to improve stability and potential speed at the start of the race.

However, working with lead requires serious safety precautions due to its toxicity. You should never cut or drill into lead without proper ventilation, eye protection, and a mask to avoid inhaling dust. Always wash your hands thoroughly after handling. Because of these risks, many modern builders opt for safer, non-toxic alternatives like tungsten putty or weights. Tungsten is denser than lead, meaning you need less volume to achieve the same weight, allowing for more flexible placement lower in the car body.

The best approach involves drilling holes in the rear of the wood block before assembly and embedding the weights, then sealing them in with wood glue or putty. Always check your specific derby's rules, as some may have restrictions on weight placement or material type. The final step is to use a precise scale to ensure you hit, but do not exceed, the 5.0-ounce limit.

Weight Material	Density	Pros	Cons	Best Use Case
Tungsten Putty	Very High	Safe, easy to mold, requires less space	More expensive	Ideal for fine-tuning weight placement
Tungsten Cubes	Very High	Extremely dense, precise	Difficult to embed, costly	For maximum weight in minimal rear space
Lead Wire/Sheet	High	Inexpensive, widely available	Toxic, requires careful handling	Traditional use, but being phased out
Zinc Weights	Medium	Safer than lead	Less dense, takes up more space	Good non-toxic alternative to lead
BBs/Screws	Low	Very accessible	Least efficient, can rattle	A last-resort option for minor adjustments

SavannahLee · Answer

My dad and I used lead fishing weights for our car. We hammered them flat and glued them into grooves we carved under the chassis. It got us to the max weight, but it was a hassle. Now I’d definitely use tungsten putty instead—no cutting, no dust, and you can just squish it into place. It’s safer for kids and way easier to work with. Just remember, the goal is 5.0 ounces on the dot.

StAshlyn · Answer

As a den leader who's seen a lot of cars, the answer is yes, but with a big "be careful." The main rule is safety first. If you use lead, an adult must do any cutting or drilling while wearing a mask. The dust is dangerous. My strong recommendation is to avoid lead altogether now. Modern tungsten weights are superior. They're safer, denser, and you can buy them pre-made to screw into the bottom. It simplifies the whole process and keeps everyone safe.

Cinna · Answer

From a competitive builder's perspective, lead is an outdated choice. While effective for weight, its low density compared to tungsten is a disadvantage. Tungsten allows you to concentrate the entire 5-ounce mass right over the rear axle in a very small package, lowering the car's center of gravity. This optimal placement can shave precious fractions of a second off your time. The investment in tungsten is minimal compared to the competitive edge it provides.

ElliottAnn · Answer

I focus on the engineering aspect. The principle is all about maximizing potential energy. You add mass to hit the 5-ounce limit because a heavier car has more momentum. Lead works, but the real trick is placement. You want the weight in the rear, about an inch in front of the back axle. This helps the car maintain speed down the track. Whether you use lead, tungsten, or another material, precise placement and accurate weighing are more critical than the material itself.