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Pinewood Derby
I wasn't really ready for the Pinewood Derby, and we had less time to work on the car than I expected. We went shopping at Lowes for materials on Saturday; the first set races, for our troop, would be Tuesday. That gave us only three days, really, to work on the car.
The block had already been cut at the previous Tuesday's meeting. I'd managed to persuade Sebastian to go with the absolute slimmest design possible; I'm no handyman, but I couldn't help noticing last year that the winners were always the slimmest designs. The design we used was flat on the bottom, and a shallow even arc on the top. I'd guess that 70% of the original block was cut away. The father who was doing the cutting on ours seemed kind of surprised and dubious about it.
The design indicated that we should drill four large holes through the side of the car and fill them with lead (or some other heavy metal). That would require very precise drilling, since there wasn't much wood left to spare. I'd guess those holes were nearly a 1/2 inch across, each! And with nothing but a cheap electric hand-held drill, I was feeling less than confident. I'm really NOT very handy at all (I'd already called my Dad and hinted that we could use his help. He told me it was a father and son type of event.
).
We were shopping at Lowes, and I asked a clerk if they had heavy metal. All he could find was 1/4 inch non-lead solder. I'd have to drill a dozen holes at least, probably more. I was feeling rather hopeless, when Teri pointed out some heavy metal stud covers - or something like that. They were basically metal plates, in a few different sizes, with spikes in the center on both ends. They were designed to be hammered into studs behind walls, for some reason. They were about 1/2 inch narrower than the car, quite heavy...hell, they were perfect. I got two, one about four inches long, the other about six inches long. I'd use either one or the other, depending on the weight.
We also looked for a small postal-type scale. They were $30. Money was tight, so I decided to see if I could find the old spring postal scale I used to use to weigh issues of the Interregnum APA. I found it almost instantly, the minute I went down to the basement. It was filthy, and I seriously doubted that it was properly calibrated or accurate.
Sometimes I'm smarter than I expect to be. I needed to calibrate that scale. But how? I didn't have any standardized weights in the house, and the post office had just closed (they have scales). It was late, and there was no time to lose. Suddenly it struck me: US coins have standard weights, and those weights are listed online. It didn't take too long to discover that five ounces equals 141.74761563 grams, and that 26 nickels and one quarter equaled 141.34 grams - a difference of only .41 of a gram, or 0.01438 of an ounce. I had my calibration.
My plan was to use some chisels to carefully dig out a space on the underside of the car, so I could sink whichever metal plate I was using at least part-way into the car body. It wouldn't be necessary for the plate to be flush with the underside of the car, but some clearance IS required - the wheels go in slots, and a low undercarriage would drag on the track - so I wanted to get at least some of the metal plate actually sunk into the car itself.
I was not feeling at all confident. Or rather, I was confident - confident that I would end up bleeding or in the hospital. Imagine digging out an area approximately 2" x 4" or 2" x 6" in a piece of light wood with nothing but a chisel, trying to make the area be flat, consistent, and about an eighth of an inch deep. Now imagine that you're a klutz like me. Bloodshed seems inevitable.
There was worse to come. When I weighed everything, neither plate weighed enough - not even close. But oddly, both of them together with all the pieces of the car came to 5 ounces exactly. I'd gain some weight from paint and such, but I'd lose some from chiseling out some of the wood. I figured it might be a wash. But how could I use BOTH plates? They were too long to fit under the car together - they were longer than the car! We'd exceed maximum length. And those spikes were long, wicked, and placed at both ends of each plate. The car would be a menace.
The smaller plate would have to go under the larger plate, of course. But that meant I'd have to chisel out an area for the large plate, and then chisel another area inside of that area for the smaller plate. Plus the larger plate would have to go over at least one axle, another problem.
I started chiseling. Somewhere in there, of course, I ended up jamming a corner of a chisel deep into the fleshy part of my left thumb. It was quite painful, and I got very crabby. I put a gardening glove on my left hand (I'm right-handed), but that made things harder. One suggestion from Teri made things easier; rather than outline the area and chisel wildly, I made cuts in the surface of the area and pried smaller sections away. In the end, I have to say that the results were better than I expected, and the process was relatively quick, if not painless. The indentation for the smaller plate was perfect; when I placed the plate in (backwards, with the spikes pointing away from the car body), it was completely flush with the rest of the surface. The larger plate stuck out slightly (if I'd dug it deeper, the axle-space would have been compromised), but that was absolutely fine.
Next I had to hammer in the metal plates. I was afraid of two things: first, that the car would break as I was hammering. It's a light, soft wood, after all. My other concern was that the metal spikes on one or both plates were likely to come out of the car's back, sticking upward into the air. Perhaps I could use a little wood putty or hot glue on any protruding spikes to make them safe...but that would be bad for aerodynamics. It also occurred to me that the spikes might go wrong in the wood as I was hammering. The chiseled-out areas were precisely the size of the plates. A small movement in any direction would mean that the plates wouldn't sink properly. Given the large size of the spikes involved, and the small size of the car body, pulling out the plates and repositioning them was likely to break the car body into pieces.
The breakage problem was solved nicely. I had the rest of the wood block that the car had been cut out from; by putting the body back in place, I had a perfectly-shaped block that supported the car body as I hammered. The plates went in straight and sunk into position beautifully. Only one pair of spikes emerged, on the back end only - and not by a large amount. Teri suggested the solution to that: rather than putty them over, why not file them down? There was a large old metal file in the basement, she was sure.
She was right; the previous owners left all sorts of weird stuff in the basement, and one item was a very large and not very raspy metal file. It filed the spikes down beautifully. It did more than that: it rubbed on the car body a bit, inevitably. And where it rubbed, it made the car far smoother than it had been after I sanded it down. So I sanded the whole thing down again with the file, as best I could. Sebastian watched and gave advice.
With the plates in place and the spikes sanded smooth, the car body felt astonishingly heavy for its size. With the wheels it came in at just a hair under 5 ounces on my scale.
We didn't have sanding primer or sealer or whatever was recommended. The instructions said to use sanding sealer, a coat of paint, sand it, another coat of paint, sand it, a final coat of paint, a finish, and then for the perfect gloss - auto wax, buffed to a high sheen. That was way too fancy for us! We put down a coat of white craft paint. It was old, and looked like cottage cheese; the coat of "paint" was invisible. Sebastian and I found a slightly newer small container of white craft paint. It gave the car a lightly whitewashed look, as if it had been dipped in whole milk. We sanded it, and later Teri and Sebastian put on another coat of new white craft paint (she made a trip to Wal-Mart). Then they sanded it, put on a coat of black paint, and a white penguin face that Sebastian designed. The black coat was very glossy but kind of rippled. I considered putting on a coat of spay shellac. Teri persuaded me not to bother.
As a last step, I decided to follow some tips I'd read online and try to polish the nails that served as axle shafts. The instructions online recommended all sorts of steps; unfortunately at that point I had about 15 minutes before we had to leave for the race, and lacked both supplies and the money to buy them. So I put each nail into the electric hand-held drill, and spun it against the fine sandpaper sponge. Then I spun them for about twenty seconds each against an old piece of Scotch-Brite, with a bit of liquid pumice soap. Washed them, dried them thoroughly, put on some powdered graphite, and hammered the wheels into place. We got to the meeting about five minutes late. It was a scene of great excitement.
Here's how the car looked:
I hoped we'd be in the top three for our den; that would qualify us to compete at the tournament next Saturday. If we weren't in the top three, though, I felt sure we'd be #4.
Why stretch this out? It's already too long. At the weigh-in, the car came in at 4.8 ounces. This concerned me, as it was a bit light - the goal is to get to 5 exactly without going over. I re-weighed it on two different scales there, getting 4.75 and 4.9.
Sebastian's car won every race it was in. He was #1 in his den. And I got a look at the times, and he was #1 in the whole pack - his average time for the three races was 2.98 seconds. No one else broke 3.0 on their average.
We won't win the tournament on Saturday. There are cars there that were produced professionally, probably at a cost of hundreds of dollars. But at least we won't be last or next-to-last every time!
I have to admit that I feel rather pleased. I'm NOT handy, not at all. But the three of us made the fastest car in the pack - and we all helped.
I want to add a little bit of weight before the tournament. I'm not sure how to do that, though. I could drill and add more metal, but I'm reluctant to do that. I could add a coat of shellac, or maybe just auto wax (would that be safe to use straight on glossy craft paint?). I'm tempted to use wood paste to fill in the gaps in the underside of the car, where the spikes went in. But if I have to lighten the car at the last minute (we can't be sure how the scales at the event will be calibrated), it might be hard to pick out the paste. Still, it would probably improve the aerodynamics to smooth out the underside.
Any thoughts?
The block had already been cut at the previous Tuesday's meeting. I'd managed to persuade Sebastian to go with the absolute slimmest design possible; I'm no handyman, but I couldn't help noticing last year that the winners were always the slimmest designs. The design we used was flat on the bottom, and a shallow even arc on the top. I'd guess that 70% of the original block was cut away. The father who was doing the cutting on ours seemed kind of surprised and dubious about it.
The design indicated that we should drill four large holes through the side of the car and fill them with lead (or some other heavy metal). That would require very precise drilling, since there wasn't much wood left to spare. I'd guess those holes were nearly a 1/2 inch across, each! And with nothing but a cheap electric hand-held drill, I was feeling less than confident. I'm really NOT very handy at all (I'd already called my Dad and hinted that we could use his help. He told me it was a father and son type of event.
).We were shopping at Lowes, and I asked a clerk if they had heavy metal. All he could find was 1/4 inch non-lead solder. I'd have to drill a dozen holes at least, probably more. I was feeling rather hopeless, when Teri pointed out some heavy metal stud covers - or something like that. They were basically metal plates, in a few different sizes, with spikes in the center on both ends. They were designed to be hammered into studs behind walls, for some reason. They were about 1/2 inch narrower than the car, quite heavy...hell, they were perfect. I got two, one about four inches long, the other about six inches long. I'd use either one or the other, depending on the weight.
We also looked for a small postal-type scale. They were $30. Money was tight, so I decided to see if I could find the old spring postal scale I used to use to weigh issues of the Interregnum APA. I found it almost instantly, the minute I went down to the basement. It was filthy, and I seriously doubted that it was properly calibrated or accurate.
Sometimes I'm smarter than I expect to be. I needed to calibrate that scale. But how? I didn't have any standardized weights in the house, and the post office had just closed (they have scales). It was late, and there was no time to lose. Suddenly it struck me: US coins have standard weights, and those weights are listed online. It didn't take too long to discover that five ounces equals 141.74761563 grams, and that 26 nickels and one quarter equaled 141.34 grams - a difference of only .41 of a gram, or 0.01438 of an ounce. I had my calibration.
My plan was to use some chisels to carefully dig out a space on the underside of the car, so I could sink whichever metal plate I was using at least part-way into the car body. It wouldn't be necessary for the plate to be flush with the underside of the car, but some clearance IS required - the wheels go in slots, and a low undercarriage would drag on the track - so I wanted to get at least some of the metal plate actually sunk into the car itself.
I was not feeling at all confident. Or rather, I was confident - confident that I would end up bleeding or in the hospital. Imagine digging out an area approximately 2" x 4" or 2" x 6" in a piece of light wood with nothing but a chisel, trying to make the area be flat, consistent, and about an eighth of an inch deep. Now imagine that you're a klutz like me. Bloodshed seems inevitable.
There was worse to come. When I weighed everything, neither plate weighed enough - not even close. But oddly, both of them together with all the pieces of the car came to 5 ounces exactly. I'd gain some weight from paint and such, but I'd lose some from chiseling out some of the wood. I figured it might be a wash. But how could I use BOTH plates? They were too long to fit under the car together - they were longer than the car! We'd exceed maximum length. And those spikes were long, wicked, and placed at both ends of each plate. The car would be a menace.
The smaller plate would have to go under the larger plate, of course. But that meant I'd have to chisel out an area for the large plate, and then chisel another area inside of that area for the smaller plate. Plus the larger plate would have to go over at least one axle, another problem.
I started chiseling. Somewhere in there, of course, I ended up jamming a corner of a chisel deep into the fleshy part of my left thumb. It was quite painful, and I got very crabby. I put a gardening glove on my left hand (I'm right-handed), but that made things harder. One suggestion from Teri made things easier; rather than outline the area and chisel wildly, I made cuts in the surface of the area and pried smaller sections away. In the end, I have to say that the results were better than I expected, and the process was relatively quick, if not painless. The indentation for the smaller plate was perfect; when I placed the plate in (backwards, with the spikes pointing away from the car body), it was completely flush with the rest of the surface. The larger plate stuck out slightly (if I'd dug it deeper, the axle-space would have been compromised), but that was absolutely fine.
Next I had to hammer in the metal plates. I was afraid of two things: first, that the car would break as I was hammering. It's a light, soft wood, after all. My other concern was that the metal spikes on one or both plates were likely to come out of the car's back, sticking upward into the air. Perhaps I could use a little wood putty or hot glue on any protruding spikes to make them safe...but that would be bad for aerodynamics. It also occurred to me that the spikes might go wrong in the wood as I was hammering. The chiseled-out areas were precisely the size of the plates. A small movement in any direction would mean that the plates wouldn't sink properly. Given the large size of the spikes involved, and the small size of the car body, pulling out the plates and repositioning them was likely to break the car body into pieces.
The breakage problem was solved nicely. I had the rest of the wood block that the car had been cut out from; by putting the body back in place, I had a perfectly-shaped block that supported the car body as I hammered. The plates went in straight and sunk into position beautifully. Only one pair of spikes emerged, on the back end only - and not by a large amount. Teri suggested the solution to that: rather than putty them over, why not file them down? There was a large old metal file in the basement, she was sure.
She was right; the previous owners left all sorts of weird stuff in the basement, and one item was a very large and not very raspy metal file. It filed the spikes down beautifully. It did more than that: it rubbed on the car body a bit, inevitably. And where it rubbed, it made the car far smoother than it had been after I sanded it down. So I sanded the whole thing down again with the file, as best I could. Sebastian watched and gave advice.
With the plates in place and the spikes sanded smooth, the car body felt astonishingly heavy for its size. With the wheels it came in at just a hair under 5 ounces on my scale.
We didn't have sanding primer or sealer or whatever was recommended. The instructions said to use sanding sealer, a coat of paint, sand it, another coat of paint, sand it, a final coat of paint, a finish, and then for the perfect gloss - auto wax, buffed to a high sheen. That was way too fancy for us! We put down a coat of white craft paint. It was old, and looked like cottage cheese; the coat of "paint" was invisible. Sebastian and I found a slightly newer small container of white craft paint. It gave the car a lightly whitewashed look, as if it had been dipped in whole milk. We sanded it, and later Teri and Sebastian put on another coat of new white craft paint (she made a trip to Wal-Mart). Then they sanded it, put on a coat of black paint, and a white penguin face that Sebastian designed. The black coat was very glossy but kind of rippled. I considered putting on a coat of spay shellac. Teri persuaded me not to bother.
As a last step, I decided to follow some tips I'd read online and try to polish the nails that served as axle shafts. The instructions online recommended all sorts of steps; unfortunately at that point I had about 15 minutes before we had to leave for the race, and lacked both supplies and the money to buy them. So I put each nail into the electric hand-held drill, and spun it against the fine sandpaper sponge. Then I spun them for about twenty seconds each against an old piece of Scotch-Brite, with a bit of liquid pumice soap. Washed them, dried them thoroughly, put on some powdered graphite, and hammered the wheels into place. We got to the meeting about five minutes late. It was a scene of great excitement.
Here's how the car looked:
I hoped we'd be in the top three for our den; that would qualify us to compete at the tournament next Saturday. If we weren't in the top three, though, I felt sure we'd be #4.
Why stretch this out? It's already too long. At the weigh-in, the car came in at 4.8 ounces. This concerned me, as it was a bit light - the goal is to get to 5 exactly without going over. I re-weighed it on two different scales there, getting 4.75 and 4.9.
Sebastian's car won every race it was in. He was #1 in his den. And I got a look at the times, and he was #1 in the whole pack - his average time for the three races was 2.98 seconds. No one else broke 3.0 on their average.
We won't win the tournament on Saturday. There are cars there that were produced professionally, probably at a cost of hundreds of dollars. But at least we won't be last or next-to-last every time!
I have to admit that I feel rather pleased. I'm NOT handy, not at all. But the three of us made the fastest car in the pack - and we all helped.
I want to add a little bit of weight before the tournament. I'm not sure how to do that, though. I could drill and add more metal, but I'm reluctant to do that. I could add a coat of shellac, or maybe just auto wax (would that be safe to use straight on glossy craft paint?). I'm tempted to use wood paste to fill in the gaps in the underside of the car, where the spikes went in. But if I have to lighten the car at the last minute (we can't be sure how the scales at the event will be calibrated), it might be hard to pick out the paste. Still, it would probably improve the aerodynamics to smooth out the underside.
Any thoughts?
no subject
Looks great and congrats of being the fastest.
PS. I have been getting all your posts on brainstorm, You got some good ideas, I hope someone picks up on them and they make it into the final schedule.
no subject