Weights for Pinewood Derby

**Jackmac** · 02-06-2010, 03:43 PM

Back when my boys were in the cubs we used pennys .drill a hole in the bottom of
the car and take it to the post office. have them scale the car and add pennys until the right weight is reached... Jackmac

**kevincan** · 02-06-2010, 03:44 PM

I have always used steel washers. I use a forstner bit the diameter of the washers and drill a hole on the bottom of the car and stack them in there. If you need more weight drill another hole for more washers.

I try to have my kids do as much of the work on their cars as possible. I will do the cutting after they come up with the design and will also drill the holes for weight. They do all the sanding and final shaping and then paint.

**mclear** · 02-06-2010, 04:10 PM

I remember my dad adding melted lead solder to the bottom of the cars in a hole we drilled. ( regular solder should work as well) He would drill out a little from the bottom if it was too heavy to always make sure it was at max weight. He would also add a little graphite to the wheel axles and make sure the wheel surfaces were sanded slightly to make them roll better. We always designed and cut out our cars with hand saws, but my dad helped with tweaking a little. We always did pretty well.

My little ones are 3 and 1 so I have a little time to weight to help build their cars.

**iceman61** · 02-06-2010, 05:29 PM

I used lead on our 1st race & tungsten weights every since. Tungsten has a bulk density almost twice that of lead allowing you to get your center of gravity closer to the rear axle making a faster car. There are plenty of places out on the net that you can get tungsten weights for PWD & plenty of places that will tell you all the little legal tricks.

**Black wallnut** · 02-06-2010, 06:08 PM

Cars that have been built in my shop that have won not only at the Pack level but also placed high at District two years running used the pre made flat weights. These were mortised into the bottom. My son always used an assortment of lead pistol bullets however he never won. Since I also cast bullets it was what was easy and available.

To answer your second question about lead. There seems to be such an over blown fear of lead. Sure lead can be hazardous but then again so can caffeine and and a whole host of other substances most us us use daily. Lead hazards can be mitigated with simple habits that all of us should already practice such as hand washing. Lead in its solid form is mostly dangerous if ingested. So do not eat the stuff. Do not eat or drink until after washing hands.

**tseavoy** · 02-06-2010, 06:08 PM

Depleted uranium is my choice. Just go to your local nuclear plant ------

Tom:

**Mr__Bill** · 02-06-2010, 06:39 PM

For my son's car we used a dollar token from the casino*. It happened to be just the right weight and it was glued on over the back wheels like a spare tire on an old DeSoto. He came in second in the finals to a car that had a real slick finish and hidden weights but didn't look as cool.

Bill

*Yes, the Cub Scout Leader was not so sure about using a gambling token.
*It was left over from Christmas time when I gave a bunch of them out to people.
*It was a while ago and dollar tokens were a lot bigger and heaver than now.

**LCHIEN** · 02-06-2010, 07:16 PM

i think when building cars for my son's time in the pack I weighed the card and came up wit the approx number of oz. af additional weight.
From the fishing dept they had some disc lead weights in oz sizes. Drilled a shallow forstner hole for the weight. Drilled a small counter sunk hole in the center of the weight for a flathead screw to secure it in the hole. made up the additoinal fractional weight by adding some small lead weights and screws to the bottom.

Using a few screws for the last fractional oz. gives you the option of removing some at weigh in time if the "official" scale says you are a bit too too heavy. That way you can go right up the 5 oz limit on a different scale without fear of major modifications at weigh in time.

**ke4fsm** · 02-06-2010, 07:41 PM

Ah... This brings back fond memories of working with my two boys in Cub Scouts. Since they are 6 years apart in age, I helped them build 8 PWD cars over a ten year period. My eldest, now a mechanical engineer, credits building the PWD cars with his interest in engineering. This is 20 year old information, so your mileage may vary.

My boys were very lucky, seven of the eight years they won the pack title and four of the years they finished first in the district.

I poured molten lead solder into cavities just at the rear axle. You want just enough weight on the front axle to make the car roll straight. Other key points are to true the wheels on a mandrel, make sure the holes on the wheels are smooth, polish the axle nails so they are very smooth (my boys liked polishing them in my lathe with white rouge.) and lots of graphite!

Remember this is supposed to be a parent-child project. let you son do as much as he is capable and use it as a teaching moment to show him the techniques.

As an aside after you son is too old to play with his cars, save them. I made shadow boxes and mounted their cars in them and gave them to them when they bought their first home. One has this displayed in his cubicle at work and the other is displayed in his workshop at home.

Sam

**dbhost** · 02-06-2010, 07:58 PM

Mind you, my Pinewood Derby build was a VERY long time ago now, but I recall mortising in a small stack of fender washers. My car was shaped very long, and curvy, with a curved taper in the middle, and it was painted bright enamel yellow, I had a chrome supercharger from a plastic model epoxied to the "hood" and a sticker from a Chiquita Banana on the "roof". I came in first place at the Pack level, but didn't do so well in district...

I think my Dad may still have that car...

**JoeyGee** · 02-06-2010, 09:25 PM

Originally posted by tseavoy

Depleted uranium is my choice. Just go to your local nuclear plant ------

Tom:

I DO live in an area that as 2 nuke plants in about 40 mile radius. Hmmm...maybe I'll just say I'm building a bomb for Libyan terrorists and power the car instead...

**Bill in Buena Park** · 02-06-2010, 10:16 PM

We poured molten lead into a (dovetail) mortised slot, bottom rearward, to hit 5 oz, then drilled out to get just under...

Originally posted by LCHIEN

Using a few screws for the last fractional oz. gives you the option of removing some at weigh in time if the "official" scale says you are a bit too too heavy.

IIRC, we used thumbtacks to get close, and adjusted by adding/removing.

**iceman61** · 02-07-2010, 02:14 AM