# Life-size revolving birdcage



## thawes (Aug 28, 2009)

One of our choreographers would like a birdcage at least 6ft in diameter, 7ft tall, portable, and able to revolve manually. Thought of copper for the cage and read the instructions for the revolve around a central axis. Transporting is the issue--the dancers must move it and sometimes lift it on stages. Any suggestions would be greatly appreciated. (The doors in and out of the studio are only 32 in wide).


----------



## NickJones (Aug 28, 2009)

My suggestion would be to use PVC piping, it's flexible, cheap, lightweight, and can easily be sprayed with bronze spray pain to look like a cage, as for the revolving bit, do a search, heaps of stuff here on revolving stages.
Nick


----------



## thawes (Aug 28, 2009)

Thanks---used pvc in the past to make a huge hoop skirt and a giant fabric covered box.


----------



## jwl868 (Aug 28, 2009)

This sounds like something that I would have to do, so here are my thoughts:

I like the PVC pipe idea, but you need to bend it, which takes heat and care. With a 6’ diameter and 7’ height, you are right at the limit of standard 10’ lengths of PVC. I don’t know what a “good” spacing will be for the vertical bars, but at 1’, you’ll need about 20. If you heat and bend the PVC pipe, you can cut a form out of plywood so that you can bend them all the same shape/curve. (You should be able to find instructions for heating and bending PVC in a theatre craft book.)

(The top where these all come together will take some thought, considering that you need to take this apart and put it back together at the venues. [perhaps a circle of plywood with PVC couplings attached along the radii.] I think there will also need to be some horizontal support (or hoop). Maybe flexible polyethylene pipe, but I can’t think of a fast assembly/disassembly method).

If the bottom/platform needs to be functional (that is, support a dancer or two), it may end up weighing in excess of 100 lb. (You mentioned that lifting might be issue.)

(The pipe in this post refers to schedule 40 PVC pipe.)

Joe


----------



## Dionysus (Aug 28, 2009)

A Note on bending PVC conduit (pipe);
The best way (without special bending tools some electricians use; they're not really cheap though) is to use a heat-gun. Heat the conduit evenly over a VERY long area, more than the area where you actually want to bend by a bit.
With a good heat gun it will take around 5 minutes for a long bend.

Best not to try to actually flex the conduit until it is all quite warm (and saggy really). Give it a nice gentle bend. If you are doing many the same, a jig is a good idea, especially for a long bend.

Most of my experience is bending for electrical use, so if you burn/scorch the conduit you have to throw it away. The same goes if you decrease the interior diameter, or have an uneven bend. And it CAN be done by hand without a jig. I've met quite a few electricians who could do flawless bends by hand and eye, time and time again.
My employer almost never bent PVC, so we used stock 90s and 45s.


----------



## derekleffew (Aug 28, 2009)

Due to the bending and rigidity issues, I think I'd choose TWC over the PVC pipe.


----------



## FatherMurphy (Aug 28, 2009)

Burning PVC gives off chlorine gas, and I think heating it releases some chlorine as well, so take proper precautions regarding ventilation, etc., along with regular fire safety measures.

I'd be tempted to avoid the hot bending, and sub in a different material for the top bends. Copper tubing is a thought, or perhaps embedding a heavy wire into ethafoam rod. It might make for a paint matching problem, but could be less trouble overall.

You might also talk to the director/designer about shrinking the diameter to 5', so that you can build two halves, instead of several sections to join together.


----------



## cdub260 (Aug 29, 2009)

This is the Electric PVC Heater/Bender I've used for heating PVC conduit. It should wotk just as well for PVC pipe.


Just be careful not to overheat it and keep a wet cloth on hand for cooling the PVC around your form.


----------



## Dionysus (Aug 30, 2009)

There is also the HOT BLANKET bender:




Or the "PVC Plug" for bending:



There is also an interesting device which heats small spring-like tubes, which you slide into the conduit, which supports it on the inside while heating and bending it.


----------

