DIY Prism Housing schematics...

I couldn't locate the thread either, so maybe its been deleted.

Alignment is quite easy, you need the apex of the rear prism to face towards the projector and the base of the front prism to face towards the screen. The angles of "displacement" will depend on the angles of the prisms used where the thicker the prisms, the less angle needed. I would attach an image, however all of my images have my logo on them and I am not permitted to display my logo as that is considered "advertising".

Your enclosure need only be wide enough to house the prisms once set at their angles (unless you intend to include a bi-pass). You may also need to have one side shorter then the other (exposed angled side of the front prism) to prevent vignetting. I'd suggest taking a look on the 235 screen thread (sticky in the main forum) for photos of the DIY prism lenses members have made for ideas.

Maybe this will help?

1. You need to work this out on a table so remove the projector from the ceiling mount if it is already installed there.
2. Start on the table with placing a piece of paper in front of the projector.
3. Place the prisms on the paper in the light path.
4. Displace the prisms so you achieve anamorphic stretch. You will need a 2.37:1 for this or you can use a 16:9 screen and 4 x 3 on the projector.
5. Trace around the prisms with a pencil.
6. Take the paper to the workshop to make your enclosure.