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Worth a Chuckle

Discussion in 'General Pinewood Derby Discussion' started by Chris Stevenson, Jan 18, 2021.

  1. Chris Stevenson

    Chris Stevenson Pinewood Ninja

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    I am planning on making our first ladder body car this year, so I wanted to experiment with a few things to prep for the build. Basically, I wanted to do a dry run and cut out a body to get one under my belt before it starts to count.

    I read a lot of stuff on this site and elsewhere; I've watched a lot of videos online for tips. My plan was to use a cordless Dremel with a router attachment to cut out the body. This is a tool I'd never used before. (I'm sure some of you are smiling already.) At first I wasn't sure if I'd be able to freehand the tool to cut out the body. I did a couple of tests and the thing ran all over the place. I tried a few different bits and settings, but nothing helped. I knew there was no way I was going to be able to cut a straight line freehand. So there was no way my son was going to be able to do it. Freehand was out, so I decided I was going to make a fence to guide the tool. Spent several hours on it. Long story short, it was better, but still very imperfect. I'm still not sure exactly why. I usually have a pretty good eye and hand for precision work. There was easily up to 1/8" variance on my "straight" lines. The Dremel router was out.

    Next experiment was with the scroll saw. Needless to say, that is the way to go. At least it was for me.

    Anyway, for all of the experienced guys and pros, maybe it's worth a chuckle to imagine a relative rookie flailing about in his garage trying to figure out what works and what doesn't.
     
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  2. Loud2ns

    Loud2ns District Champion

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    We've all been there at some point!
     
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  3. Mojo Racing

    Mojo Racing National Contender Pro Racer

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    I know a bunch of people who use routers, but I swear by my scroll saw.

    The scroll saw is a lot easier to control, and it puts less stress on the body as it is being made.
     
    Last edited: Jan 18, 2021
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  4. HurriCrane Racing

    HurriCrane Racing PWD Royalty 25+ Pro Race Wins! Pro Racer National Champion

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    At least your dremel experiment didn't result in a trip to the ER. :)
     
  5. Mojo Racing

    Mojo Racing National Contender Pro Racer

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    RIGHT! 10 toes and almost 10 fingers! :rolleyes:
     
  6. Prozach2

    Prozach2 Workshop Leader

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    Chris, I'm absolutely terrible at wood working, so I feel your pain. I really enjoy it. I just don't have any idea what I'm doing. My dad was a surgeon and he wanted his kids to be surgeons. He never wanted to risk us hurting our hands, so, growing up, I wasn't allowed anywhere near a power tool.

    Now, I've got a pretty respectable wood working station (drill press, scroll saw, power drill, belt sander, etc.). I just don't have a clue how to properly use any of it. I'm sure most of the guys on this forum would get a kick out of watching me and my son trying to figure out how to put a drill bit in, change a scroll saw blade, etc. Thanks to a lot of people on this forum and the good people at youtube, we somehow Forrest Gump our way through it. And although our cars are consistently the ugliest, they almost always win.
     
  7. Chris Stevenson

    Chris Stevenson Pinewood Ninja

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    My dad was a banker and a tightwad, so he did everything himself - home repairs, oil changes, etc. I grew up not knowing that you could hire people to do all of that stuff. So I grew up using tools and I'm pretty handy. The problem is, most of my DIY experience has been working on houses and automobiles. PWD cars are much smaller scale, with much smaller tolerances than what I'm used to. So I'm having to learn to use a whole new set of tools and processes. It's fun though. And always feels good being an old dog learning a few new tricks.
     
  8. Chris Stevenson

    Chris Stevenson Pinewood Ninja

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    Pinewood Derby Car 2021.jpg

    Here's this year's car, "The Flash."
     
    Last edited: Feb 1, 2021
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  9. Prozach2

    Prozach2 Workshop Leader

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    Looks great. Is that vinyl?

    I think we’re going to finish up ours tomorrow, but this is what we have so far. DF4CD783-E581-4908-8353-E46BCE2B7E95.jpeg 80E761C0-3605-4990-9210-35636B4FD5FB.jpeg
     

    Attached Files:

  10. Mojo Racing

    Mojo Racing National Contender Pro Racer

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    Yep... that looks like a vinyl covering on the car.

    Car looks good, Chris!
     
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  11. Chris Stevenson

    Chris Stevenson Pinewood Ninja

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    Yes, vinyl. I ordered like 40 sheets of different colors on Amazon for $15. Lifetime supply. I will never paint again. So much easier, faster and less mess (and cheaper). Sharpied the sides; I think it looks good.

    I see you are using the tungsten bar instead of cubes in the rear. I didn't really discover the bar until I'd already ordered all of my stuff. As it turns out, though, I was having to move weight forward to have a less aggressive COG and to get more weight on the DFW. I don't think I'd want more weight out of the body, though I had some room to cut more out. I left a 1/4" brace in the middle. I cut out a body on a test run and the frame flexed too much in the middle for my taste. I see you have the thin brace that would solve that. Our cut out body weighed 6.5 grams before we glued the 1/64" plywood over the weight pockets. The COG ended up being very close to 1/2"; call it 9/16". That was a little more aggressive than we wanted and that was after we rolled 3 cubes all the way forward in the weight pocket and put a bead of tungsten putty by the DFW. Ended up with 15.8 grams on the DFW. Hope that's enough and we don't pop a wheelie. Point being, I felt like we took about all the weight out of the body that we wanted to. We left the nose at 9/16" to give it just a little more strength since it was going to be so thin. Also left a little more meat at the front axle. We could have shaved a little from both of those and done away with the brace in the middle to get the minimum possible weight, but we were weighing that against flex and potential breakage. One of the cool parts of the build is that I would explain to my son that we could do X, which might be faster, or Y, which would be safer and he had the choice. (That way if it flies off the track or breaks it's not all my fault.)

    Overall, I'm very happy with the way it turned out. We'll see what the times are, but I don't think I'll ever build anything other than a ladder body with vinyl cover again.
     
  12. Mojo Racing

    Mojo Racing National Contender Pro Racer

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    Ladder bodies may not be the easiest to build, but they are pretty much the lightest, and they are sturdy also.

    Good job! Keep at it, and you will see improvements as you build more.
     
  13. Chris Stevenson

    Chris Stevenson Pinewood Ninja

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    Are pros doing less than 1/2" COG or less than 15g on the DFW? I was skeered to go under those benchmarks.
     
  14. Prozach2

    Prozach2 Workshop Leader

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    I used the tungsten cubes last year. This year, I have the bars, cubes, and putty. I plan on glueing the big bar behind the rear axle. I'll use double sided tape in the pocket in front of the axle and we plan on just moving them around until we get it right. If any pros want to make a suggestion for how much steer I should use and/or the ideal amount of weight to put on the DFW, your advice is always appreciated!

    I've never done a ladder body like that, so no clue how it will hold up. The tungsten bars came with a sample body, so we just tried to build our car to look like that. I'm a little nervous about the nose on ours. Specifically, the wood in front of the DFW started off as 1/4", but I shaved off 1/16" to move in the DFW. So, it looks like the thinest part of the entire body is the part of the body that will be taking the bulk of the impact. I'm thinking about cutting a couple more bodies and leaving a little more meat on the nose and making the right side a little wider so it will still be 1/4" after I shave off the 1/16".

    I have two boys, so we're going to do one car with fenders and one without. Other than the fenders, I'm going to do my best to make them identical. I'm interested to see how much the fenders help... or hurt.
     
  15. Loud2ns

    Loud2ns District Champion

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    You won't wheelie with that weight on the front unless it's a rough track.
     
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  16. Chris Stevenson

    Chris Stevenson Pinewood Ninja

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    I cut my test body exactly like yours. Doing a dry run allowed me to see where any weaknesses were in my process and in the finished product. I took the 1/16" off the DFW side just like you did. No. 1, it made that frame member very thin, as you experienced, and No. 2 I didn't like the way it looked. What I decided to do was to take 1/16" off each side at the point of the axles. So I drew a diagonal line from the front of the middle frame member, through the 1/6" mark at the axle line to the nose of the body. I used a bench sander to remove the material to the line. Taking 1/16" off each side on a diagonal allowed us to keep more of that frame member at the DFW and it also looked symmetrical. It's hard to tell from the pic of our car since it's a side view.

    Only other observation I have is not to glue in that bar so you can reuse it. Tungsten is expensive (about $20/4oz./car) and I don't see any point in leaving it in a car once it's been raced and is just sitting on a display shelf. The double sided tape I got (carpet tape), is plenty strong. I'm not worried about our weights shifting or falling out, especially with the vinyl and foil tape on the bottom also holding it in place.
     
  17. Chris Stevenson

    Chris Stevenson Pinewood Ninja

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    Thank you for reducing my anxiety level this week, lol. Our track is a 35' BestTrack, but there is a rough spot at the transition in one lane that has caused cars to come off the track in the past.
     
  18. Prozach2

    Prozach2 Workshop Leader

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    Yeah, I think I'm going to follow your advise on the double sided tape. If the weight doesn't feel secure, I can always go back and glue it. Doing 2 cars a year, I'm sure I've already spent hundreds on Tungsten weights.
     
  19. Chris Stevenson

    Chris Stevenson Pinewood Ninja

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    One thing you can do to make the tape work better is to also cut strips for the sides of the weight pocket in addition to the bottom. I didn't do that because it felt secure enough for me, but I thought about it.
     
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  20. Prozach2

    Prozach2 Workshop Leader

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    If I do vinyl next year, do I need to buy a heat gun to put it on? If not, is there a relatively cheap and easy way to put it on?
     

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