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Help with hollow soccer ball nightlight

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Forum topic by LiveEdge posted 09-01-2014 09:07 PM 1393 views 0 times favorited 11 replies Add to Favorites Watch
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LiveEdge

486 posts in 1080 days


09-01-2014 09:07 PM

Topic tags/keywords: soccer ball nightlight question clamp

After building a TARDIS nightlight for my son (see projects) my daughter requested a soccer ball nightlight. I laughed and told her, “that would be impossible” knowing full well I’ve seen soccer balls on Lumberjocks. So now I’ve set out to do it but want to gather tips and tricks from people. I envision a hollow sphere of hexagons with the pentagons of the ball left empty. The light and socket are at least 6-7 inches tall so the ball will probably be a foot in diameter. I’m going to keep the hexes flat rather than attempted some kind of actual spherical surface.

I’ve always been attracted to solid wood over plywood. Am I asking for trouble with wood movement?
How does one clamp the hexagons together while gluing?
What thickness do you think would be good for the pieces? 1/2”? Thinner?


11 replies so far

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splatman

557 posts in 858 days


#1 posted 09-02-2014 04:51 AM

I’ve built Platonic Solids out of plywood, mainly 1/2” fir and pine. Joined with biscuits. Never used solid wood, so would not know if wood movement would be an issue. Before glue-up, you could experiment with grain orientation. Use tape to hold the pieces while you experiment. When gluing, tape together, then use large rubber bands to apply clamping force. You’ll need enough rubber bands so 3 bands cross each hex face, over the joints. Cut up an old innertube for rubber bands. If you have a vacuum clamping system, you could try that. Tape temporary pentagons over the penta-spaces, to keep the membrane from being sucked in. You’ll only need to go to -2 or -3 psi below ambient pressure; anything greater is overkill.

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LiveEdge

486 posts in 1080 days


#2 posted 09-02-2014 04:04 PM

I’m thinking of using quaking aspen because it is both white and fairly dimensionally stable.

Taping will definitely be a good idea. I’m not sure I can do an all at once gluing because I have to install the light and base. I’m probably going to build it half at a time and put the two halves together like bowls. Maybe the joints don’t have to be as strong as possible as it will only see very light use (mainly sitting on a dresser).

Anybody have good ideas for how to most easily cut the hexes? I read a few of the blogs and project pieces. I’m thinking of setting the table saw blade to a 20.9 degree angle and cutting strips of wood at the proper width then using the compound miter saw at 20.9 to cut the rest of the hexagon out of the strip of wood. Is there a better way?

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splatman

557 posts in 858 days


#3 posted 09-03-2014 04:59 AM

I’ve cut pentagons on the tablesaw using patterns, so that should also work for cutting hexagons. Tack the pattern to the back of the hex blank with 2 brads. Your patterns will need to be larger, so they can slide along the fence w/o the blank interfering. If you make your patterns 1” larger all around, just set the fence 1” from the side of the blade opposite the fence when cutting out the hexes. If the blade tilts to the left, put the fence on the right. Test with scrap material first.
The CMS trick you mention is the way to go if you wish not to make patterns.
You could leave the bottom hex unglued during glue-up, then install the light and base, then glue it in.
Building 2 halves, then gluing them together later, may lead to alignment issues.

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LiveEdge

486 posts in 1080 days


#4 posted 09-03-2014 03:51 PM

I’m starting to visualize enough to start goofing around and trying some of this. It may be a process of trial and error.

For the two halves what I may do is cut the interfacing hexagons in half so I’m actually joining two hemispheres rather than trying to join all the hexagon edges together. I agree it would probably be an alignment nightmare to fit that together.

For the first ring of hexes at the bottom, I think what I may do is glue them together and place the ring upside down inside a small square of surrounding wood strips. The strips will constrain the hexes from spreading laterally. If I then put some weight on the top I would imagine the weight would compress the joints like weight on an arch. At least that works in my mind… :)

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LiveEdge

486 posts in 1080 days


#5 posted 09-03-2014 08:58 PM

Here’s a question: Does the miter angle change if I change the size of the hexagon? My brain says no, but I’d appreciate some confirmation on that.

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splatman

557 posts in 858 days


#6 posted 09-04-2014 03:25 AM

Weights only on top will put tension on the sides. The key is to put an equal amount of force on each joint. Hence, vacuum or rubber bands. Tape the half hexes together on both sides before assembly, if you use either method. I don’t know of any other way to apply clamping force.
Whether you build it golf ball size or cathedral size, all the angles are the same.

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splatman

557 posts in 858 days


#7 posted 09-05-2014 06:37 AM

I misunderstood your last paragraph. Using strips to contain 5 hexes in a 5-sided pyramid shape, then adding weights, would work fine. First, place something flat on top, to help keep the hexes aligned.

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LiveEdge

486 posts in 1080 days


#8 posted 09-09-2014 03:56 AM

Man. I forgot how much of a pain it is to cut hexes. I was familiar with the task from making a Settlers of Catan board, but adding a bevel to the cut just adds a whole ‘nuther layer of complexity. I printed out a hex and taped it to the wood and then scribed the hex onto the wood with a knife and straight edge. Then I worked as hard as I could to make that hex as accurate as possible. When I was satisfied I made that the template and then scribed it onto more wood to make more hexes with lots of futzing and shaving and nibbling at the edges. I can’t glue up the first ring until my daughter goes to bed. We’ll see how it goes together. I’ll try to take a picture and post tomorrow.

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LiveEdge

486 posts in 1080 days


#9 posted 09-09-2014 04:45 PM

You can see they did not come together perfectly. I may have to switch to customizing each and every hex as I continue to build it. It’s sitting on the little jig I built to hold the pieces in place. I taped them and glued them and then put a 5 pound weight on the top of the dome.

View viktorija's profile

viktorija

2 posts in 815 days


#10 posted 09-15-2014 08:20 AM

Hello, LiveEdge, I hope your project is going fine, I just wanted to ask you, how you estimated the lenght of the sides of hexagones and pentagones, since you chosen to do it a bit bigger than standart soccer ball. Did you make your own calculation with CAD or adjusted data of standart soccer ball, used in other’s projects (All other project I found in LumberJocks were of the same soccer ball size) Would it be just simple proportion – if the ball is 1,5 times bigger, so then every side is 1,5 times longer as well? Or not?

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LiveEdge

486 posts in 1080 days


#11 posted 09-15-2014 02:45 PM

I started another thread with my exploits on this project (see the thread in tools about bevel angle). It turns out that the bevel of 20.9 stays the same no matter the size of the ball. For my purposes the ball needed to be big enough to house a light and base. I found a truncated icosahedron calculator and went from there with a little finger crossing. Here’s the latest picture. This iteration is smaller than the one above but still somewhat bigger than an actual ball.

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