B's Pinewood Derby Car

We've known for a couple months that the annual Pinewood Derby was coming up and that it is a big deal, but Bentley did not start working on his car until this past weekend. Matt was in Barrow last week and he went again this week, so opa was asked to help Bentley create a car. 

The project did not get started until I got involved. I googled fast pinewood derby cars and was directed to the Boys' Life site. They had hundreds of photos of pinewood derby cars in all sorts of odd shapes: a dragon head, an octopus, a sarcophagus, an aquarium, R2-D2, a tongue, two fried eggs (?!?), and even Elvis. 

After looking at these cars, I had three thoughts: First: I can't believe these cars go fast. Second: Who knew there were that many good wood carvers in scouting?! And my final thought: Bentley should have started on his car weeks ago.

I moved on from looking at odd cars to reading the tips for making a fast pinewood derby car. As I suspected dragon heads and sarcophagi are not an optimal shape for speed. Also, when I showed the sarcophagus and dragon head cars to Bentley he said he was not interested in making a one-of-a-kind car. He wanted something simple. Yeah! I had Bentley read the tips for fast cars with me. The main point we learned is that a wedge shape is an easy way to create a fast car. Bentley said he wanted a wedge. That was good progress on the project: he decided on a shape.

We also read that you should bake your block of wood for 2 hours at 250 degrees to make it lighter. After you bake it lighter, then you make it heavier in the back by adding lead. Bentley asked us to bake his car. We did. 

On Saturday B and opa started the hard work on the project. They went over to a friend's house to have him help them turn B's block of wood into a wedge shape with his table saw. Bentley did the cutting with both adults providing assistance. Then B and opa came home and B used sand paper to make the surface smooth. Opa drilled holes on the back end and the underside and then opa, Matt, and Bentley went outside to use a propane torch to melt lead to pour in the holes. Given the tools needed to accomplish this step, Bentley did more watching than participating.

The next step was to put a layer or two of primer paint on the vehicle. This was done Saturday evening and again on Monday. After a few rounds of sanding and spray painting, the vehicle was ready for its final paint job. Bentley had gone to the store on Saturday and chosen the paint color: blue. Bentley and Opa took turns spraying the paint on.

The final step was to add the tires. The fast car tips we had read advised that you test a number of different nails for straightness and then you pick the best four. Our problem was we only had four nails--the ones that came with kit. B and Opa tested them using the power drill. They were not as straight as could be, but they were all we had. Bentley and Opa polished them a little, added wax, and then graphite. 

Hammering the wheels on to the car was a little tricky. As sometimes happens in projects like this, one of the axles (AKA nails) created a hairline crack in the wood when it was nailed in. Oops! Glue was added to strengthen that area, but there wasn't much else that could be done. (Maybe it's a good idea to hammer the axles in place before you do anything else (and then remove them)? If your block of wood cracks, you can replace it right at the start of the project.)

When Bentley was testing the car after it was finished he noticed that only three of the wheels rotated when he moved the car. I inspected the wheels carefully and saw that one of the wheels was a little higher than the others so it didn't touch the ground when the car moved. Score! I remembered reading on the tip list that you have less friction if only three wheels touch the ground. I told Bentley this was a good thing, not a problem.

Why 16? Bentley told us 16 is 2 times 8.