Originally Posted by Brian Gibson
It is a P502HL-2 NEC. Screen size is 150" at 14'. I hope to use 1/4 MDF for the screen.
If the projector can be mounted at roughly the same height as the top of the screen (or higher), that would be pretty ideal.
A 150" screen made of panels would work best if you can level, fill and smooth all the seams, then grab a ~$10 gallon of ColorPlace flat interior LightBase/white from Wal-Mart or a white primer from the store of your choice to give it a nice coating of white (which might want a quick/light sanding) before spraying your screen mix onto it.
A screen that size can use a mix of:
-9tubes of FolkArt metallic (they're little 2oz tubes..around $1.75each at Wal-Mart art/craft section). You'll only want two of them to be "gunmetal grey" FolkArt metallic..the other seven should be some "Pearl" metallic FolkArt and "Sterlingsilver" metallic FolkArt. That'll make a medium-grey screen with higher gain and a brighter image.
-18oz matte polyurethane (a quart of matte Varethane poly is ~$12 at HomeDepot)
So the mix will cost around $30 altogether, plus ~$10 for the gallon of flat-white and your panel filling/smoothing supplies.
You can also mix a little of the inexpensive white paint half'n'half (or 2parts paint with 1part water if the paint is already kinda thin) with some water to test how well your sprayer handles really thin paint. You'll be looking for it to lay out a pretty smooth freckled mist onto the surface without coughing/sputtering or periodically sneezing big globs of paint.
If the sprayer doesn't have an adjustment/setting that behaves with thin paint, the least expensive sprayers that work well cost around $40-$50...I'm not sure if that would even be an option though.
Did you already read about spraying duster-coats/multiple fast light coatings?