Need a HUGE aluminum sphere.

[MillenniumFalsehood]

Okay, I've got a large project in mind which will require a hollow aluminum sphere, about 2 meters wide. No, it's not a small thermal exhaust port . . .

It needs to be thin-walled and hollow, and it must be aluminum because it'll have to cope with pressure. Does anyone here have a supplier I can talk to?

[en'til Zog]

2 silo tops? Try farm suppliers?

[Joseph C. Brown]

Are you are referring to the full-scale TIE that's being discussed in the Star Wars area?

Anyways, if you plan to pursue a project of this size, the only advice I have is:

- keep it affordable

- build so that it can travel, or be stored.

The only way that I can conceive of hitting both of those points is to build a mock-up in cardboard ($). When you are happy with your shapes, and the parts break-down, just fiberglass the cardboard. Paint, and you're done.

Then you will have no need for an insanely priced aluminum sphere.

[Kylwell]

What kind of pressures? You may find that a fiberglass sphere will be much, much cheaper.

That being said you could ask these guys for a quote: http://www.edon.com/finials_spheres_spires.htm

[MillenniumFalsehood]

Are you are referring to the full-scale TIE that's being discussed in the Star Wars area?

Anyways, if you plan to pursue a project of this size, the only advice I have is:

- keep it affordable

- build so that it can travel, or be stored.

The only way that I can conceive of hitting both of those points is to build a mock-up in cardboard ($). When you are happy with your shapes, and the parts break-down, just fiberglass the cardboard. Paint, and you're done.

Then you will have no need for an insanely priced aluminum sphere.

Actually, yeah.

I figure it would be simpler to construct than an X-wing and cheaper than the Millennium Falcon.

So fiberglass would be cheaper. I thought an aluminum sphere would be better because then I wouldn't have to create a sphere myself, but since a fiberglass one would be cheaper, then I should probably pursue that route.

I'm a practical guy (says the dude wanting to build a full-scale TIE Fighter for building's sake ), so I would probably draw everything by hand first, then build a computer model, unfold it in Pepakura and, build a 1:12 scale paper model to make sure the cardboard templates would work, then build a full-size mock-up in cardboard, fiberglass it if it works, then detail the interior and build the wings. I would definitely reinforce the wings with a PVC pipe, then reinforce that with more fiberglass (if I can afford it). The reason for all the reinforcement is I plan to build a full cockpit into it. I would of course build it to collapse for transport. There are a lot of activities in our town that would benefit from the attention a full-size TIE fighter would gather, so I will want it collapsible.

The big concern would be how to get the cockpit onto the wings, but I'm sure I could get a couple of guys to help me find a crane or hoist.

[Johnnycrash]

A full sized TIE Interceptor has been built. If I remember correctly, by the guys of htr 501st.

http://www.flickr.com/photos/jojopet/4897526148/

http://www.flickr.com/photos/evilbenius/4886618766/

http://www.flickr.com/photos/evilbenius/4886018041/

http://www.flickr.com/photos/evilbenius/4886616666/

http://www.flickr.com/photos/dabidk/4896699464/

I have pics from the convention showing it being put together. I'm trying to find the link...

There was even at 1/2 AT-AT.

[Johnnycrash]

OK, found the link. Check out page 2, right at the top.

http://www.flickr.com/photos/starwarsbl ... 365192239/


There are a lot of other great shots in that collection as well.

[MillenniumFalsehood]

That was the *inspiration* for this project, John. Thanks for the pics, though! Those will really help.

[pocketpencil]

An aluminum sphere that size would probably run you $1K+ easy

[Rogviler]

Something I've been getting into lately is using polar fleece with fiberglass resin. For one thing it's cheaper than fiberglass mat, but if you do it right you essentially end up with a 1/8"" thick piece of fiberglass with just one layer of it, versus a paper-thin layer with the mat.

Basically you just create a frame or skeleton for your shape out of plywood or MDF, and you can even use foam if you need to sculpt something (make sure your resin is compatible with the foam first). Then you stretch polar fleece over it (this is where the bargain bin at the fabric store comes in handy), stapling it to the frame. Lastly, you soak it in fiberglass resin. And I mean SOAK it, you want it to go all the way through. It helps if you have access to the inside. You'll definitely want to buy the resin by the gallon, but I wouldn't mix more than a cupful at a time unless you're really fast.

And man, if that isn't strong enough, just keep adding layers. But it's tough stuff. Then you can use fiberglass filler (hair or gel) or body filler to smooth it out.

It's also a great way to make new door panels for your car or custom speaker enclosures. I've even seen it used for bumpers.

But it would be a fairly easy, cheap, and lightweight way to make a TIE cockpit, especially when it comes to the inside.

-Rog

[TonyT]

Stainless steel

http://www.alibaba.com/product-gs/32621 ... _ball.html

acrylic note price!!!

http://www.alibaba.com/product-gs/24847 ... _ball.html

[TonyT]

have you considered a couple of domes off

http://www.skyshedpod.com/

[MillenniumFalsehood]

Something I've been getting into lately is using polar fleece with fiberglass resin. For one thing it's cheaper than fiberglass mat, but if you do it right you essentially end up with a 1/8"" thick piece of fiberglass with just one layer of it, versus a paper-thin layer with the mat.

Basically you just create a frame or skeleton for your shape out of plywood or MDF, and you can even use foam if you need to sculpt something (make sure your resin is compatible with the foam first). Then you stretch polar fleece over it (this is where the bargain bin at the fabric store comes in handy), stapling it to the frame. Lastly, you soak it in fiberglass resin. And I mean SOAK it, you want it to go all the way through. It helps if you have access to the inside. You'll definitely want to buy the resin by the gallon, but I wouldn't mix more than a cupful at a time unless you're really fast.

And man, if that isn't strong enough, just keep adding layers. But it's tough stuff. Then you can use fiberglass filler (hair or gel) or body filler to smooth it out.

It's also a great way to make new door panels for your car or custom speaker enclosures. I've even seen it used for bumpers.

But it would be a fairly easy, cheap, and lightweight way to make a TIE cockpit, especially when it comes to the inside.

-Rog

Now *THAT* is a great idea! Now I just need to find copious quantities of cardboard . . .

[Tankmodeler]

Something I've been getting into lately is using polar fleece with fiberglass resin. For one thing it's cheaper than fiberglass mat, but if you do it right you essentially end up with a 1/8"" thick piece of fiberglass with just one layer of it, versus a paper-thin layer with the mat.
-Rog

Now *THAT* is a great idea! Now I just need to find copious quantities of cardboard . . .

OK, let me add some thoughts from the engineering point of view...

Using the polar fleece will give you a stiff and heavy structure but not one with a lot of actual strength. The strength is in the fibers and even then, the longer and straighter, the better. Polar fleece is a mat of short and kinked fibres. You will end up with a large sphere that is heavy and weak for it's weight. That may be acceptable, but it will be heavy. If you want to increase strength without increasing weight much, what you want is to lay down a layer or two of fibreglass on the mould, add the polar fleece and then lay down a layer or two of fibreglass on top of the fleece. If you want to save a LOT of weight, exchange the polar fleece with balsa wood (also allows you to change the thickness & build in interior/exterior contours based on the shape of the balsa). If it is 1:1, then strength & mass wil be important & I suspect that the polar fleece method will leave you too heavy and too brittle to withstand any real handling.

HTH

Paul

[Rogviler]

Nah, polar fleece is plenty strong. It's not like felt, it's still a woven fabric, it just has been fluffed so there's lots of surface area.

Trust me, if this stuff can be used to withstand the pressures involved in subwoofer enclosures it'll definitely hold up for a static prop.

I mean, if people are going to be climbing in and out of it all the time then that's a whole different discussion...

-Rog

[Umi_Ryuzuki]

...

I mean, if people are going to be climbing in and out of it all the time then that's a whole different discussion...

-Rog

Well yeah, everyone will want to put time into the Star Wars game console
that is set up in the dash, and view screen...

Wait, that would be an x'wing wouldn't it....

[publiusr]

Now I have seen orange spheres along high tension power lines that are quite large...
http://tanawiremarker.com/

They do custom builds. It might be better for a death star though. Do a search for spherical wire markers.

[MillenniumFalsehood]

That would have been great, but they only go up to 52" in diameter. The sphere I need would be about 72" in diameter.

[Rocketeer]

A couple things come to mind.

The way Ed "Big Daddy" Roth did all his wild show cars was to build a mockup out of wood, wadded newspapers, and plaster, then fiberglass over that, then knock out the plaster stuff with a big hammer. (That is, he built a male mold.) The fiberglass shell became the car body. Cheap and easy to change if he didn't like something.

The other way to build large stuff is to make a male mold out of foam and then fiberglass over that, then dissolve or carve away the foam. If you use polyester resin, you have to use urethane foam; if you use epoxy resin you can get away with (cheaper) styrofoam.

[MillenniumFalsehood]

Yeah, and the styrofoam can be eaten away with acetone, too. Good idea!