Help me design this... diy "ball" rollercoaster

Art Mulder

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London, Ontario
Hey Folks,

Yesterday we spent the day with the kids (and their cousins families...) at the Ontario Science Center in Toronto. Great place to explore with the kids.

In the "Kidspark" area -- for the 8+under set -- there was this very cool build-it-yourself rollercoaster toy that I snapped a few shots of:
IMG_2614_3.jpg IMG_2620.jpg

They play on this with hard rubber balls about 3" in diameter. My youngest (aged 5-and-a-half) played on this for almost 40 minutes straight.

So I spend the next half hour staring at it and trying to figure out how I can duplicate this.
The trick, I would think, is finding the right rubber extrusion for the top of the track. Here is a close up of the end:
IMG_2619_2.jpg

My other thought was to try and scale this down to use a golf ball (or similar sized rubber ball). That would be a much smaller size toy, a little easier to fit in the basement! but again, trying to come up with the track part of the toy is the trick. I tried googling around for rubber extrusions, but didn't really find any ready-made products that seemed right. I wondered about garage door weather stripping, but that isn't the right shape either.

So I thought I'd turn to the bright folks out here on the the forum...
Ever seen a rubber extrusion like this? Any idea where I could find one -- and yes, cost is an issue.
OR, any thoughts about scaling this down to a golf-ball sized structure? Again, any ideas about a good rubber extrusion that would work?

I think a rubber track is mandatory. I've made some other small marble-works toys and wooden track is hard, and can lead to balls bouncing around. I think a rubber track would be more yielding and lead to a smoother action of the ball rolling along, more likely to stay on track.

...art
 
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Hi Art.

The way I see it you don't need a single rubber profile, I think that you could get away easyly by using a rubber cord similar to that used on pressure cookers.

You could route a pair of semicircular grooves of its diameter with the right router bit and just glue them in place with cyonacrilate or rubber cement.

You should spread them apart so that the ball would run on them just above its diameter, that would give it a lot of stability.
The loops and double loops, might be tricky to do and maybe you'll need to use bent wood or that ply that you have in US that is so flexible and foldable, I don't remember its name.:dunno:

See included sketch, I hope this helps.
 

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Is there a way to contact the people at the Science Center to see if this material is available? It seems that it is ideal for making curves and loops, but has the provision to be able to join 2 pieces of it easily with some plastic or wood dowel rod. If that doesn't work, then the other suggestions above would be my next course of action. Jim.
 
Vaughn said:
Closed cell foam backer rod would probably do the trick...

You mean like copper water pipe insulation? Won't that tear out really easily?
The rubber extrusion I saw was really robust, and yet still had some flex.

Jim O'Dell said:
Is there a way to contact the people at the Science Center to see if this material is available? It seems that it is ideal for making curves and loops, but has the provision to be able to join 2 pieces of it easily with some plastic or wood dowel rod.

You're exactly right about the ability to join two pieces using a dowel. I think that's mandatory.
The science center doesn't really give that sort of a contact number, but I may start digging for that. I still like the idea of scaling it down, though, which makes me want to find some other sort of extrusion that would work.

Hi Art.

The way I see it you don't need a single rubber profile, I think that you could get away easyly by using a rubber cord similar to that used on pressure cookers.

That might work, Toni, but I think your solution is too wide. If you look again at the original photos, you'll see that the body of the piece is just plywood on edge - 3/4" by my estimation. I think it might work, but I think it would really complicate the construction. Cutting a curve in a sheet of plywood is straighforward. But cutting a curve and then attaching a platform to it would be tough.

wait, that gives me an idea... what about TWO pieces of identical plywood set parallel to each other. Then get a simple piece of vinyl hose, slit it, and slip it over each of the pieces...

Like this:
ball-rollercoaster.jpg

Hmm, still more work than one piece of plywood...

I need to go browsing through the Borg and daydream some more about this...
 
art that extrusion, resembles the bumpper guards on grocery store checkout conveyors or possibly some other industrial bumper guard possibly a boat dock quard extrusion.
 
Is there a way to contact the people at the Science Center to see if this material is available?

Well I tried this today and got a very quick response: First, it was designed and fabricated in house. Second, the rubber extrusion was also a custom proprietary design and not for sale.

Considering that I discovered this afternoon that they also sell their exhibits (and/or their design services, I think) I'm not that surprised at the words "proprietary" and "not for sale".

Oh well, he did encourage me to come up with my own solution -- suggested the same thing I'd already thought of in my previous post, where I doodled that drawing with two parallel wood tracks.

Oh yeah, and I wandered all over the local Borg tonight, looking at plumbing stuff, window stuff, weather stripping stuff, and didn't really find anything that seemed to quite suite my thoughts.

I'm not worried. Sometimes I "percolate" on ideas for months at a time before coming up with new ideas or approaches.

...art
 
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