Originally Posted by MississippiMan
Welcome back. But be forewarned, your desire to have a Torus Screen ain't dead yet...............
RS-MaxxMudd LL is no slouch in the gain dept. I can assure you it has the ability to put up an image you'll be pleased with.
As far as the ability to maintain better contrast under ambient light conditions, RS-MaxxMudd LL will be a better choice than S-I-L-V-E-R .
So ok...this "Torus" business. Well no problemo there,Senior Aussie. 6 mm Sintra is an excellent material. It has just the right combination of rigidity and controlled flexibility to bend evenly across the gradual degree required for a Torus-oriented curve without the need for much support along the curve. That means you can anchor one end then bend the Sintra into a desired curve, then plot out the supportive structural members wherever you feel they are most needed. I am certain that you will be able to find a Plastic Sheeting Mfg who has a selection of Rigid Expanded PVC Foam Board. You want it in White if possible, but take it in any color you can get it...especially if it cost less.
Sintra also comes in 1/4" thick size, and that is even more rigid, yet still retains enough flexibility. Cost a bundle more than the 6mm though.
What will please you most is the fact that once bent into shape, Sintra doesn't try to fight it's way into some other shape, making it very easy to work with when designing a supportive Cradle.
But.......you will still want to paint it before you bend it into it's permanent position.The paint is more than flexible enough so no worries there. I'd be interested in helping you decide what type design would be best suited to use for your Cradle. It won't need to be complex or heavy at all...just secure the ends and the center, so as to allow the Sintra's own curvature stresses to maintain the overall radius curve you'll need. I am thinking Screws only, situated around the perimeter edges.
So what say you?
just as I was giving up on a torus screen. Thanks to you MississippiMan, I'm excited again.
Enough so I even did a super crude
scale mock up of a torus screen just to satisfy myself that rigid plastic can comfortably take a two-axis bend. It appears it does.
Here's two pics, my model was done with milk container plastic.. -Even made it 16:9!
MississippiMan, I am interested on what ideas you have for the cradle. All I've thought of so far is a simple wooden frame. And if I understand you correctly, rather than going through all the effort of carefully drawing out curves and then using a jigsaw to cut them out of the wood. Instead put risers on each corner of the frame, attach the Sintra to each raised corner and also on the middle of each length and let it curve the way it wants to?
I did a quick 3d mockup of how I've understood the construction idea.
i used the torus calc spreadsheet provided by Pjackso here.
Based on a screen of 91"x51", with a viewing distance of about 9' and a couch about 6' wide. -The spreed sheet gives me pretty low numbers for the risers. giving depths of 2.25" horizontal and 0.8" down the vertical sides. Which is what I've used in the model.
However Vince_B here.
had a 88"x48" screen, similar size to mine, who after using much bigger values reduced them and ended up with depths of 3.5" horizontal and 1.75" vertical. He reported being very happy with this and I'm thinking of going closer to what he used.
Rang up about Sintra (Forex here in Oz), and so far if I want a single sheet larger than 4'x8', the next size is 10'x5' and that only comes in 3mm or 5mm thicknesses.
That said, we move into our new rental this Friday and then I can properly measure the lounge room and get a firm idea of what size screen and seating position we'll be using.