Round screen

June 11, 2008 10:18 PM

I want to build a circular screen.

Screen will be used for rear projection. I've got material for the screen itself, I'm just looking for a frame to pull it into a circular shape. It will probably be about 8 feet in diameter. I'm imagining something like a giant circular needlepoint form, or a reflector like the type used for lighting, but I might be off there. Any ideas for a large circular form? Bonus if it's transportable. Maybe I'm not thinking about this hard enough, but I can't think of anything that large and circular that would work.

posted by mike_bling to grab bag (5 comments total)

Maybe fiberglass tent poles.
posted by weapons-grade pandemonium at 10:34 PM on June 11 [1 favorite]

Buy a used circular trampoline and use the frame.
posted by Krrrlson at 10:37 PM on June 11

My guess is that the photography reflectors you mention in your question are going to be your best bet. Reflectors and diffusers both get pretty large. I'm sure somewhere will have a 96" collapsible diffuser to sell. But if you can't find one that big, just buy two four foot diffusers and use the material from the rim to make your own.

My second idea was the frame from an above-ground pool. The pool we had when I was a kid had an upper and lower rail that served to stabalize the thin metal walls. It was composed of 3ft long metal sections that slid together to make a circle with an inner groove for the wall to fit. You might be able to find an 8ft pool kit and use the railing, though most pools are larger (10-15ft). On that train of thought, maybe a pool or hot tub cover could be modified.

Ultimately, I'd probably just build one by cutting an 8ft diameter circle of plywood as a form and then soaking strips of wooden house trim until flexible and bending them into place around the form. Use nails to hold them in position on the form while they dry. Once dry, remove the pieces, which will stay bent in an arc. Then dovetail the pieces together, glue and voila. An eight foot wooden frame.
posted by Jeff Howard at 11:42 PM on June 11

Seconding the tent poles. (If you don't know how those work, they're flexible and meant to slip through channels in cupola tents and the such, creating the shape). You could just get a large enough canvas of some sort and either sew a hem to it that you can slip the poles through or just attach some sort of loops at sufficiently frequent intervals alongside the edge.. And it would be quite transportable.
posted by Authorized User at 2:38 AM on June 12

Irrigation tubing. 1" irrigation tubing, held together with barbed connectors, is the material of choise for large (4' diameter) hula hoops. It's fairly rigid, but holds a circular shape well, and if evenly tensioned, should get stronger.

You could cut the tubing into four sections for easier transport. If you're going to be repeatedly assembling/collapsing it, you'd probably want to put one barbed connector in each piece permanently, and grind down the exposed barbs on the opposite side to make it easier to take apart. You need to soak the tubing in very hot water to soften it up to insert the connectors normally.
posted by adamrice at 7:09 AM on June 12