Dome shaped objects

[Risu]

So I've got a few projects right now that are at a stand still because they require large dome-shaped pieces and I have no idea how to make them. One is 2" in diameter and the other is 10". Can anybody suggest any ways to scratch build these pieces symmetrically without the use of a lathe or other expensive machinery?

 

[WarMachine]

Half size Dalek?

Cutting a plastic ball of some sort surely has to be the best option for the 2" ones.

Hopefully someone with some knowhow can help.

 

[Sigma-LS]

How are the domes supposed to look? Half sphere? Flatter, steeper?

Have you tried shopping around for the different security domes (for cameras) at Lowes and Home Depot?

For the 2 inch, bottom of a beer can?

 

[patsmear]

What about xmas ornamets that you can cut in half?

 

[hankey01]

Ikea stainless steel bowls for the 10"?

 

[Sigma-LS]

Actually if you need a lot, you can just find one thing that meets your specs and mold it.

Ornaments like patsmear said would be great. Hobbly lobbly also carries a big variety of wood and foam spheres of every size that would work.

 

[smoothrat]

Would clear plastic work for your application? I've used plastic ornament balls, which come in halves, from the craft store. They come in a variety of sizes, such as for your smaller 2" dome.

For the 10", IIRC the Big Daddy costume hereabouts used a security camera protective dome or something like that. Hope this helps...

NOTE: apparently I need typing lessons, judging by how many similar posts were made in the time it took me to write that.

 

[Risu]

I probably should have explained what I need a little better. Dome-shaped was the best way I could describe the general shape, but neither piece is a half sphere. The smaller one is actually a quarter inch thick disk with a slight doming to it, mostly flat in the center and sloping off at the edges. The larger piece is a ring with an OD of about 10 inches. It's basically a dome with the top cut off and the center cut out. I was hoping to get some kind of advice on how to finish the edge of something like a board or a sheet of plastic, etc to get the same angle or slope all the way around it. I don't have access to a pottery wheel, otherwise that would be the method I'd use.

 

[Knightjar]

Cut a set of profiles from styrene. carefully apply epoxy putty or filler, allow to cure and then sand. Takes care to get a good finish on curved surfaces. The more profiles you use, the easier it is to get the curve right.

 

[kuzushi]

pepakukra?

 

[Risu]

I would use pepakura, but I can't make 3d models.

The other technique sounds good, but I've still not been able to track down any places locally that sell styrene.

 

[WarMachine]

What about cutting cardboard discs, gluing them on top of each other and then using bondo to fill in the step-like spaces, to get the correct shape after sanding it down? You could then make a cast of it.

Not sure if that would work but it seems like it'd be easy enough, at least for the 2" domes.

 

[epilepticsquirl]

If pepakura is an option for you, I'd be more than willing to help you with your 3D work. Just send me a sketch and i'll see what I can come up with.

 

[Risu]

That would be great, thanks.

 

[division 6]

Any hardware store will carry styrene "for sale" signs that you could use.

Since you are looking for low profile curves what about bowls.
Plastic bowls can be found cheap and cut up easily by scribing with a knife and snapping the excess off or using a dremel.

If you go the bondo route you can cast it into a bowl or as suggested laying it over a layered sub structure and forming it with a stiff sheet in the correct profile shape you want.

E...