Cardboard Sled Race Help

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Durham68
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Cardboard Sled Race Help

Post by Durham68 »

Hi Guys. I am looking to enter my kids in a cardboard sled race at the local ski slope and need some input on materials. I am thinking that a triple-wall corrugated sheet will provide a sturdy base. I considered building up a runner sled with this, but I'm not sure it's worth it. Assuming we keep it simple and will have a large, flat bottom surface, what combination of cardboard, duct tape, paint, sealant, and wax would produce the slickest surface for something like this?

Rules are as follows:

CONTEST RULES
1. Design & Build a sled of any size using ONLY cardboard, duct tape, paint and any adhesive. Wax is ok.
2. NO metal or wood will be allowed. Use of any “illegal materials” will lead to immediate disqualification.
3. Sleds must have at least one passenger and max of 4 passengers on a sled.
4. You may have a rescue team “assisting the sled over the finish line”.
5. A liability waiver must be signed by all passengers and participants.
6. Helmets required for all sled passengers.
Awards will be given out for best design, funniest, most creative helmet and fastest speed.
"Unattended children will be given an espresso and a puppy"
tfbncc
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Re: Cardboard Sled Race Help

Post by tfbncc »

Couple of quick questions:

Does this need to be steerable? Or is it a straight downhill shot?
Any size restrictions?
How many passengers are you planning?
Is Duct Tape the only tape allowed? (think about using Flex Tape or similar)
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Durham68
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Re: Cardboard Sled Race Help

Post by Durham68 »

Doesn't need to be steerable. It is a straight shot. Stability/tracking would be nice as I plan on putting the kids in there. I would like it to hold 4 people. Either all 4 kids (12, 9, 7, 5), or the three oldest and myself. My wife's view of the hill and the final product may determine if the 5yr-old will be allowed in. There are no size restrictions as far as I know, but I'd like to keep the cost under $200 so that could be a factor. The rules say duct tape, but I'm not sure how well the sleds will be inspected. Never been to one of these before.
"Unattended children will be given an espresso and a puppy"
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g-man
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Re: Cardboard Sled Race Help

Post by g-man »

Forget tape. Soaking the base in a 2-part epoxy adhesive (ANY adhesive...) to create a hardened shell would likely help add additional strength to the triple-wall construction. Cutting thin wedges crosswise out of the base so that the front edge lifts in a curve (vs an angular transition) will help get snow in front of the sled transitioned to the flat-bottomed planing surface underneath without 'plowing'. Similar to the advantages for weight distribution of pinewood racers, put the heavier kid in the back (also helps for keeping the sled on plane). If you can manage to keep any duct tape on the inside, a single, solid planing surface should work best. I'd almost consider constructing a two-layer sled, with epoxy sandwiched between the layers. If you can manage to build each layer out of single piece of cardboard, it would minimize seams (you'd really only have two holding the sides to the curve along the front edge), and would maximize resilience against unknown sledding surface. Think 'cheap plastic sled', except made of cardboard and epoxy. Wax the hell out of the bottom, and you should do pretty well.

A runner sled would be a possibility for a smaller, lighter passenger, and would likely FLY down the hill, but you're looking at such a huge number of failure points that simpler is probably better.

The alternative is to just cut holes in one side of a fridge box and pile 4 big people inside. Which would be funny as hell.
Igitur qui desiderat pacem, praeparet bellum
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g-man
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Re: Cardboard Sled Race Help

Post by g-man »

Also, I'd advise putting the 3 older kids in and having yourself as the 'rescue team' at the bottom in case it flattens enough that they don't make it across the line on momentum alone.
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Durham68
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Re: Cardboard Sled Race Help

Post by Durham68 »

g-man wrote: Wed Feb 13, 2019 6:38 pm Forget tape. Soaking the base in a 2-part epoxy adhesive (ANY adhesive...) to create a hardened shell would likely help add additional strength to the triple-wall construction. Cutting thin wedges crosswise out of the base so that the front edge lifts in a curve (vs an angular transition) will help get snow in front of the sled transitioned to the flat-bottomed planing surface underneath without 'plowing'. Similar to the advantages for weight distribution of pinewood racers, put the heavier kid in the back (also helps for keeping the sled on plane). If you can manage to keep any duct tape on the inside, a single, solid planing surface should work best. I'd almost consider constructing a two-layer sled, with epoxy sandwiched between the layers. If you can manage to build each layer out of single piece of cardboard, it would minimize seams (you'd really only have two holding the sides to the curve along the front edge), and would maximize resilience against unknown sledding surface. Think 'cheap plastic sled', except made of cardboard and epoxy. Wax the hell out of the bottom, and you should do pretty well.

A runner sled would be a possibility for a smaller, lighter passenger, and would likely FLY down the hill, but you're looking at such a huge number of failure points that simpler is probably better.

The alternative is to just cut holes in one side of a fridge box and pile 4 big people inside. Which would be funny as hell.
I love the idea of interior cuts to allow contouring the front edge. Pourable 2-part epoxy could be an amazing contact surface. Seems like the base would have to be really rigid to keep it from cracking though.
"Unattended children will be given an espresso and a puppy"
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Durham68
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Re: Cardboard Sled Race Help

Post by Durham68 »

g-man wrote: Wed Feb 13, 2019 6:39 pm Also, I'd advise putting the 3 older kids in and having yourself as the 'rescue team' at the bottom in case it flattens enough that they don't make it across the line on momentum alone.
I'd rather give them a huge push and let the chips fall where they may.
"Unattended children will be given an espresso and a puppy"
BDK
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Re: Cardboard Sled Race Help

Post by BDK »

A) Hard pack or powder

B) What kind of temp? Frozen, saturated cardboard can be quite strong.

I assume you're rather far from MB - we get disposable totes in, at times, which are very strong cardboard.
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Durham68
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Re: Cardboard Sled Race Help

Post by Durham68 »

MB?

Race is at powder ridge in CT. Don’t let the name fool you. Unless it snows the night before, there won’t be any powder. I assume they will have the snow machines running the night before the race. The event is in mid March so I’d guess the daytime temps will be just north of freezing.
"Unattended children will be given an espresso and a puppy"
tfbncc
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Re: Cardboard Sled Race Help

Post by tfbncc »

I went and watched some videos of cardboard sled races on Youtube. I saw a lot of spinning and sideways sledding. If the sled is too short or strictly flat bottomed, it's very difficult to keep it going straight. And, once you start turning, you lose energy and slow down. So, if you are out to win this thing, then I would suggest a sled that has a long, narrow body with a keel on the bottom. Something like a Viking longship (also looks neat). Also, once you have built your sled, since any adhesive is allowed, I would coat the whole bottom with fiberglass resin to seal the cardboard and add rigidity to the sliding surface then wax the heck out of it.

Whatever you do, we want pics and vids
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