Building and rigging custom projection screen

[DRU]

Need to build a projection screen for our upcoming production. Our rigging points are DS of proscenium and are 16' apart (left over from the original tour of Phantom). The overall size of the screen is 18' wide and 11'4" tall. The perimeter has some added, not structural, detail that creates a decorated frame. It must break down into pieces no bigger than 8'x16'. It will be hung at a trim around 30', static during production. One time use, not saving. One day load-in with IATSE stagehands.

Original idea (see attachment): build four steel flat frames out of 1.5" square box tube. Bolt them together along the edges. Stretch a fabric over the whole frame and staple to wood on back/sides. Rated eye-bolt (in red, cable in blue) at the bottom. Screw on decorated frame pieces, then fly out.

Do I need more structure in the frames for the span? Will 1.5" square tube work, or should I bump it up to something bigger? Is there a better way?

 

[MNicolai]

May be easiest to treat this like a cyc. Grommet and and webbing along top of projection fabric, sew a pipe hem into the bottom, and forgo a rigid frame altogether. Depending on your throw distance and on-stage wind currents, it may or may not be necessary to fully tension the fabric on all sides. If it doesn't have to move during the show, you could probably hang it, overlay the architectural trim from the front, and spot tack the fabric to the backside of the architectural trim to try and make it a little cleaner finish.

 

[BillConnerFASTC]

I worry about the frame in your design bending or folding a little at the joints between the panels. It could telescope through the screen or result in a bad wrinkle. If nothing else, a few stiffeners across joints.

 

[DRU]

I worry about the frame in your design bending or folding a little at the joints between the panels. It could telescope through the screen or result in a bad wrinkle. If nothing else, a few stiffeners across joints.

The decorative frame might help with that as well, but I will add some on the back. Do you see any problem with the design and the distance it has to span? My gut says it won't bend a whole lot, but I don't have Structural Design for the Stage in front of me right now to check.

 

[BillConnerFASTC]

Basically, no, not with pick points so near side verticals. Its just the tendency to "fold" a little at joints that concerned me.

Decorative frame and weight and center of gravity - I think you need to be concerned about the weigh of the decorative part tending to tilt the frame forward at the top, if a little tilt would matter. Maybe not, and maybe as simple as adding some ballast on rear.

I assume the decorative frame makes Mike's idea not work, but then I don't know what that is. Rococo in wood and chicken wire and glop or ultra minimalist in mylar - has an impact.

 

[DRU]

Decorative frame and weight and center of gravity - I think you need to be concerned about the weigh of the decorative part tending to tilt the frame forward at the top, if a little tilt would matter. Maybe not, and maybe as simple as adding some ballast on rear.

I thought about the same thing. I can reduce the thickness of the plywood for that, and the stiffeners on the back will help counterbalance.

 

[ruinexplorer]

What are you using for screen material? That may affect how you build the frame as different materials require different amount of tension to maintain a smooth surface.

 

[DVBortle]

Ladder trusses may be a workable solution based on something like the Dapeier stagescreen http://www.draperinc.com/documents.aspx (using this screen as an example of concept )
less weight 4 smaller pieces no joints in the center.

 

[DRU]

What are you using for screen material? That may affect how you build the frame as different materials require different amount of tension to maintain a smooth surface.

Heavy muslin right now. I think I have some extra in stock.

 

[bobgaggle]

I don't see anything wrong with the design, agree with Bills suggestion to add stiffeners on the back.

My company has success with a method very similar to the stagescreen method. We use it to hang drops on ships where rigidity of the whole drop is necessary (rather than letting it swing freely like on land) We built flat trusses out of 1x1 box tube. Bolt them together in whatever perimeter shape your screen needs to be, and hang from the top truss. Fabric is tied to the inside chord of the truss and decorative bits can get attached to the rest of the framing wherever convenient, overlapping the fabric ties.

 

[ruinexplorer]

I agree that truss style frames are easiest and work best with keeping a square frame. If it's in your budget, you may want to add screen goo to the muslin for a better image.