Glass Bead Projection Screen

By Sean Michael Ragan
Category: Home, Furniture
Time Required: 8 hours over 3 days
Difficulty: Moderate

Here’s a method for applying a high-gain optical projection surface using common, inexpensive materials—specifically, flat white interior latex paint and glass sandblasting media. It began as a series of experiments to produce a DIY “screen paint” by directly mixing these two ingredients. Though failing in themselves, these tests led to the serendipitous discovery of this process.

Steps

Step #1: Determine screen size

Set the projector up as you intend to use it. Turn it on.
Measure the height and width of the image with a tape.
Plan the size of your screen accordingly.
My image is 42" high and about 75" wide. A 4x8' (48x96") panel of hardboard was therefore a convenient surface to use as a screen. I could've cut it down, but the extra area doesn't look bad, and may be useful someday.

Conclusion

As it is, this gravity-based application method requires a screen, separate from the wall, that can be positioned horizontally to sprinkle on the glass. I'm not at all convinced that my method for building the screen (nor for attaching it to the wall) is the best one. Improve it!

The final surface--glass beads embedded in latex house paint--is surprisingly robust. I was at first concerned that flexion of the screen would cause the beads to flake off. Fortunately, the latex paint retains plenty of flexibility, at least over the few weeks my prototypes have existed. I almost think you could go so far as applying it to a thin surface that actually rolls up.

Another pleasant surprise was that, at viewing distances, the surface treatment is remarkably tolerant of small imperfections, and does not require a very smooth texture. I believe it could even be applied directly to a textured wall, and the next step is to figure out a convenient process for doing so, thus eliminating the need for a separate screen altogether. Stay tuned!

7 Responses to Glass Bead Projection Screen

Goli Mohammadi on April 4th, 2011 at 6:17 pm said:

Cool ideas, Mike! Please share if you work through any of these applications.

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Sean Michael Ragan on April 10th, 2011 at 2:40 am said:

Not necessary, IMO. This stuff is 80 grit, making it 190 micrometers in diameter on average. Silicosis is not a risk until the particles get down to 10 micrometers or less, so that’s a pretty comfortable margin. Particles also need to be crystalline (and of particular crystal structures) to cause silicosis, and glass beads are not crystalline, but amorphous. They’re also not pure SiO2. But of course anyone who is concerned about it should not take my word for it, and should err on the side of caution, and should wear a respirator.

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Sean Michael Ragan on June 7th, 2011 at 4:52 pm said:

Thank you! Yes, the whole scheme I’ve used to hang the thing from the wall is really pretty crappy. It has worked, so far, for me, but I would not officially recommend it to anyone. A french cleat, per Scott Baker’s comment, above, seems like the best and most elegant way to do it. When/if I do it again, I’d use a french cleat.

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Sean Michael Ragan on September 12th, 2011 at 9:47 pm said:

Hi Lance,

Actually my projector is mounted on a 2′ piece of MDF shelving from the hardware store. I’ve drilled holes in the shelf and put bolts and washers through that secure the projector to the shelf using its built-in threaded mounting holes.

The shelf, in turn, is mounted to the wall using “Cable Shelf Brackets” from The Container Store:

http://www.containerstore.com/shop/shelvingSale/wallMountedShelving/brackets?productId=10001032

The nice thing about these brackets, for this purpose, is that the shelf doesn’t have to be mounted at 90 degrees to the wall. You can stand under it and lift it up, eliminating tension on the cables, and then adjust the four corners up and down as you want to adjust the image, then let the shelf go, and gravity will hold it in place. So it’s easy to adjust.

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Sean Michael Ragan on October 27th, 2011 at 11:33 pm said:

Jay-

Thanks so much for your comment, for your enthusiasm, and for your reported results and advice to others. Glad you’re pleased, thanks for reading and doing and sharing.

Cheers-
SMR

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Sean Michael Ragan on June 3rd, 2012 at 5:53 pm said:

I dunno about cloth, but my first experiments were on cardboard, and I
observed when I discarded them that the top layer of the cardboard
bearing the mixture of paint and sprinkled on beads could be peeled
off (indeed, it tended to come off as a continuous sheet) and rolled
up without significant flaking of the paint and/or beads. Granted,
the paint was relatively fresh at that time, but latex stays flexible
for awhile. I keep meaning to experiment with this, actually, but
haven’t had the time yet.

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Chuck on June 5th, 2012 at 3:49 pm said:

I made the PVC outdoor movie screen from the Geek Dad books, and I am using a 5′x9′ sign banner as the screen. It works great because it is simple to roll up and store. My guess is that rolling up something like this will either lead to permanent wrinkling or cracking.

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