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How to make a huge hollow sphere? Answered

I am planning on a project and I need to know how to make a huge hollow sphere?

I was thinking about using paper mache around a huge sphere, but dont know where to start, like what would i paper mache around. I would like the sphere to be about 30"-40" in diameter.

Even though Ive said it, please remember it needs to be about 30"-40" before you answer your question. Thanks!

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rabotat
rabotat

1 year ago

Does anyone have any ideas about creating a hollow structure so that I can fill it with water, freeze it and then remove the structure to reveal the frozen ice? The structure needs to be around 3 metres in diameter so quite large! We have considered sculpting it but would be good to have another option!! Thanks. neil

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Orngrimm
Orngrimm

Reply 1 year ago

That's over 14 cubic meter of water... Over 14 tons of weight... A structure to support that I would say metal. Removal of said structure will be difficult...
I propably would tackle the problem by making slabs, freezing them together. Then, carving out the rough shape and honing it with a metallic shaver in the form of a semicircle.

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Orngrimm
Orngrimm

1 year ago

From tungsten? Be sure you add salt to it...
Some will get the reference ;)

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AussieAlf
AussieAlf

Reply 1 year ago

The snail.....you forgot to mention the snail!!

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Orngrimm
Orngrimm

Reply 1 year ago

i see, you got the reference! :)

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UlucB
UlucB

2 years ago

Ok got a 36" balloon and paper mache on it but it's taking forever to dry. Hair drying is out thanks to Mr. TimtheScarecrow's logic. I need it ready soon and I'm not sure if it will hold its integrity, anyone try this out and know how it turns out?

1540363575812383009336.jpg
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anv3D
anv3D

3 years ago

Paper mache around a beach ball?

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Eli_Z
Eli_Z

4 years ago

I just figured this out for myself, it'll work for any scale.

You need to already have a two-piece mold for a non-hollow sphere, aka a ball or marble or whatever. So, make that if you don't have it. Now you need a sphere shaped plug. That'll exclude your casting material from where it is in the mold, like a bubble. Now you need some supporting structure to hold that sphere in place, and you need that supporting structure to be either so thin that the holes it leaves are easily plugged later or non-intrusive, or that can become part of the sphere. IMHO fishing line is perfect but super hard to work with unless you want a clear fishing line running through your mold. Perhaps cast some little triangles or pins out of the same material you're casting with and then break them off and sand down the nubs after.

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TimTheScarecrow
TimTheScarecrow

8 years ago

a beach ball, as said previously, or one of those large bouncy balls that the people in walmart get mad at you for playing with.
just be sure that when you cover it in the mache, that you let it dry in a room of the same tempurature.
if you store it in a warmer place, so itll dry faster, the ball will end up expanding cause of the heat and crack your hard work; if you store it in a cool place, the ball could shrink and your sphere will come out deformed.

Ive actually made a sphere for a project of mine using one of those balls, it cost me about a dollar to buy it. heres a link to the instructable i made using the ball.
https://www.instructables.com/id/How-To-Big-Sister-Bioshock-2-HelmetLamp/step2/Paper-Mache/

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rickharris
rickharris

9 years ago

If your not happy with Steve's explanation (when he gives it) You can easily form a 1/4 circle curve in some scrap wood and use that to sweep round the pile of sand or damp soil to form your hemisphere.

As in picture

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steveastrouk
steveastrouk

Answer 9 years ago

+1. Thanks.

Probably cover that with clingfilm/ saran wrap afterwards, to keep the water in the pile ?

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canucksgirl
canucksgirl

9 years ago

Go to a dollar store (discount type store), and buy yourself a beach ball that's 30"-40" in diameter. Then fill it up with air and paper mache it with newspaper. Then when it's dried, let the air out of the beach ball, and remove it. You can then patch the hole used to get the beach ball out with some more newspaper and paper mache or glue.

Bonus, you'll have a beach ball for summer. ;)

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rickharris
rickharris

Answer 9 years ago

And if the beach ball is clean you can return it and get your money back claiming it wasn't big enough or something!!

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steveastrouk
steveastrouk

9 years ago

Balloon ?
Big pile of sand, shaped with a board.
Clay
Fitness ball ?

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Hiyadudez
Hiyadudez

Answer 9 years ago

Sorry, I forgot to mention.

I would like it to be at a minimal cost as Im low on money at the moment :P

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steveastrouk
steveastrouk

Answer 9 years ago

big pile of sand wins

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Hiyadudez
Hiyadudez

Answer 9 years ago

Its a shame I dont live half a mile from the beach/dunes :(

*sarcams btw*

But please explian how I would make a sphere mouled around sand? XD

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steveastrouk
steveastrouk

Answer 9 years ago

You're going to form two half spheres on the pile, then join them.You're going to shape a pile of damp sand with the end of a large can, which will form a perfect sphere pretty quickly, then you can papier mache straight onto that. Repeat.

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Hiyadudez
Hiyadudez

Answer 9 years ago

A large can?

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steveastrouk
steveastrouk

Answer 9 years ago

Coffee can should be big enough - the circular end wil average the surface out for you. Make the pile roughly round first - you can use a piece of wood cut to a curve or something.

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Re-design
Re-design

Answer 9 years ago

I like the balloon idea. Now all you gotta do is find a big baloon. Ought to be some on the internet.