Just a really quick update… I’ve started on the build of the frame for my projection screen. Current progress shown below.
This is a pretty simple construction. It’s basically half of an octagon – although for various reasons the odd and even sides are not exactly of equal length – and will force the hardboard I’m using for the screen to adopt the semi-circular shape that I need. The board will be tacked to the vertical frame members which are designed to be flat against that point of the curve.
The frame is pine baton, 44m x 44m, mostly joined together with 120mm x 7mm concrete screws – which have proven excellent for building frames provided I drill proper pilot holes. The angle joints were all cut on my trusty mitre saw and are joined with multiple 3.5mm screws. This holds them together but does allow them to move a bit and since the frame needs to be stiff, they needed re-inforcing, so each joint is backed up by a strong steel plate that braces it. Now it only moves as far as the wood itself will bend.
Next, I have to put on the hardboard itself. This is likely to be tricky so I will test-fit everything first and trim to size. And once this is in place I will add a tripod of supporting legs to hold the screen the correct distance from the floor, and the side of the frame that contacts the wall – only one can do this, because there’s a radiator on the wall on the other side, unfortunately – will also be screwed into the wall battens using brackets. This should keep the whole assembly rigidly in place.
Finally, I will mount a gantry to the rear of the frame to hold the projectors. I need to do some tests to measure the picture displacement distance for my projectors, so I won’t know exactly where to fit the gantry until I’ve done that test. So that’s probably a job for after Christmas.
Oh, and speaking of which, Merry Christmas to all my reader 🙂