building giant globe

[norwintd]

hey guys I wanted to see anyone had a suggestion on how to build a giant globe approximatley 4' to 5' diameter. It is for a float so it doesn't have to be very durable, its a one time use thing. I am trying to avoid paper mache and chicken wire at this point . I may be going the giant beach ball route but wanted to see what other ways are out there.

thanks in advance

[MaddMaxx]

I've actually used a weather balloon. Check out this link:
http://scientificsonline.com/Product.asp?pn=3041755

6' foot diameter is $25 plus shipping.
Use latex paint - no spray cans! Much cheaper than anything you could construct.

[gafftaper]

Build a frame out of plywood and cover with a stretchy fabric like Tricot, a heavy fabric like commando cloth, or even a heavy plastic painters drop cloth.

You could probably figure out a way to cut up hula hoops to make the framework.

A Dasco Pro Giant Beam Compass would be useful for drawing your ribs on the plywood... just attach it to any 1/2" pole and you can draw huge circles. You can get them from Sears's catalog for under $10.

And all of these ideas are more expensive than a weather balloon... although they are more sturdy.

[Van]

A float company here in town builds most things like globes, animals etc. using 1/8" - 1/4" mild steel rod. They build an armature then, typically, cover it on Hardware cloth or chicken wire, then whatever material they need for finishing. These guys build floats for the Rose bowl parade, and all over the US. Even if you don't use this particular technicque in this instance, it is a great way to build really complex structures very simply. One guy I used to work with built a lifesized black bear skull, in wireframe, in about two hours. It was beautiful watching it come together.

[icewolf08]

I have seen people laminate insulation foam sheets together and then carve globes from that.

[gafftaper]

Originally Posted by icewolf08

I have seen people laminate insulation foam sheets together and then carve globes from that.

That's a great idea Alex. There are a lot of potential ways to do this with foam. You could buy that weather balloon MaddMax mentioned and use it as a mold to pour a bunch of A-B foam in. Depending on where you are you can get a giant block of foam and carve it down. Or like Alex said get smaller blocks of foam and glue them together (I like the heavy duty version of Liquid Nails).

[avkid]

If you are going to work with foam, get some dust masks, electric carving knives and a hot knife to finish it off cleanly.
An air compressor with a long hose and a Shop-Vac aren't a bad idea either!

[norwintd]

thanks for the responses everyone. the weather balloon idea might just be perfect fit. The other ideas are more than I want to get into on this project but I will definatly put the other ideas to use at some point
thanks again guys.

[Van]

Originally Posted by avkid

If you are going to work with foam, .................................. and a Shop-Vac aren't a bad idea either!

Van is on a safety kick this week.
While you will definately want a shop vac, be careful to empty it completely of dust, etc. prior to using it to vacuum up foam. During my last big foam tree project, I shocked the crap outta myself on several occasions due to the build up of static electricity in the shop vac I was using. These types of discharges can be explosive if they occur inside the vac whilst flamable dust is present.
Depending on the foam being used and the tools being used a standard "particlulate" dust mask may not be sufficient, and the use of a respirator may be indicated. EPE foam can be really noxious when it gets warmed up even by a saw, or sander.
Ok taking my safety hat off, Anybody want to play with matches ?

[gafftaper]

Originally Posted by Van

Ok taking my safety hat off, Anybody want to play with matches ?

Only if we are throwing them in a barrel of copper wire and kerosene!