DIY screen frame for rear projection

[pmolsonmus]

Hi,

First real venture into projection. After research and cost analysis and trying to accomplish multiple uses in future productions, I am planning use a grey Chameleon Cloth for 2 rear projection screens about 8' x 8'. The size is designed to frame a stage (SR and SL) and also act as "legs" that mask side entrances in a black box, or be a freestanding screen that could easily come in and out of a production.

The plan is that it would fit on a standard rolling 4x8 truck and could be used in multiple set ups in the future. After several search attempts I didn't find anything that seemed to adapt so I'm posting here.

My thought is a simple PVC construction framed in wood that would allow for tying the screen at the top and allow for a pipe in the pocket at the bottom of the screen. I'm trying to minimize weight so it can be a freestanding unit. I'm also planning to put a space in the bottom to add sandbag weights. (it may be used without the truck) A mock-up diagram is attached.

View attachment Screen and Frame.pdf

Thoughts?

 

[MarshallPope]

A few thoughts came to mind. I'm not sure if just having it tied at the top and piped at the bottom will give you a flat enough surface. You may end up with some vertical-ish folds angling toward the bottom center. Also, I'm not certain that PVC will stay straight enough. I'm thinking that it may bow down in the center. My initial approach, keeping in mind both budget and weight, would be to construct a frame of around 2" EMT (electrical conduit) that is around 3-4 inches larger than the fabric on each side and fasten the fabric to the frame with bungee ties on around 6-8" centers. I would then fasten this to your wood frame with either conduit clamps or plumbers' tape at maybe 3 points per side.

 

[65535]

construct a frame of around 2" GAC (electrical conduit)

I'm guessing you mean EMT (Electrical Metallic Conduit) not GAC (Galvanized Aircraft Cable).

I would probably just frame it out of wood if you're going to use wood.

I would probably use this stuff.

McMaster-Carr

 

[MarshallPope]

I'm guessing you mean EMT (Electrical Metallic Conduit) not GAC (Galvanized Aircraft Cable).

Very correct. I'm blaming lack of sleep and fingers getting ahead of my brain.

 

[JohnHartman]

Having done this before, a few thoughts..

1. the biggest challenge will be keeping the screen tensioned. 8' PVC is going to bow and cause wrinkles.
2. Next challenge is going to be keeping the frame minimal but resisting flexing forward and back and keeping it square.
3. attaching the material without causing ripples will be it's own fun.

I ended up building a frame wrapping the screens around a 1 by 3 frame flat (similar to a Broadway style) to smooth the edges and then add a 1 by 3 perpendicular frame (similar to Hollywood style) to secure the frame obviously no crossbars . We then attached the frames to a flat with a hole cut in as a frame for the screen.
I think you will need to build a nice rigid frame on the wagon to fit the screen into.

or buy a nice fastfold screen..

 

[pmolsonmus]

Thanks for everyone's input. That's why I'm asking before I start buying supplies.


1. I will find a light, cheap but rigid alternative to the PVC
2. My thought to help resist the flexing was to have holes cut in the 1x6s (see diagram) at the top and bottom of the vertical - attach the top horizontal to the vertical at a rigid right angle. The 1x6 covering should help with side to side sway and the weights should prevent front/back (in theory anyway)
3. I assumed the pole would sit between the PVC(alternative) and the 1x6 and gravity would give enough tension on an 8' screen. If I have to attach to the vertical then I would do so w/ bungee or ....

If I need to build a rigid screen frame and then insert it onto something that can be moved it would certainly change the diagram. I've never worked with Chameleon Cloth so we may go with trial and error. Thankfully I've got almost 2 months to solve the problem and the screen material is relatively cheap. >$100 USD/ each screen.