[David Fitz-Henr]

I have created the raw components for the main mirror cell. They are basically carbon fibre castings, which is different to the usual fibreglass castings which typically use polyester resin and chopped strand mat to fill the mold reasonably quickly. I'm not sure how good my technique really is, but I think it would be a lot stronger for cast components. I simply lay up numerous layers of cloth / tow in the mold, wetting each layer with epoxy as I go. It is very, very tedious and time consuming, but I end up with components that have about 80 layers of carbon fibre cloth saturated with epoxy resin. I'll coin the term "lami-casting" to describe it (don't know if anyone else has done this). Anyway, the results can be seen in the attachments. I use MDF board, a router and circle cutting jig that I made to create the molds in a single process. I saw this technique on the web - I find it creates better molds than the pattern / plaster technique described in N.E. Howards book and elsewhere. Once the epoxy has set, I sand (using a belt sander) the surface of the casting flush with the top face of the mdf mold, and then separate the mold from the casting. If done carefully, the mold is also reusable, although here I ended up breaking some parts of the molds (if you don't wax everything fully the epoxy will stick mdf sections together).

The mirror cell is designed to support a 12.5" conical mirror, and comprises three parts: 1. Supporting ring, 2. Collimation Support and 3. Mirror Attachment plate. Collimation will be achieved using push/pull screws which will be set near the outer periphery, giving both finer adjustment control as well as greater stability due to wide spacing. The mirror itself will be attached to the Mirror Attachment plate via a threaded rod screwed into an embedded nut set in the back of the mirror (a la Royce style). I am also planning on allowing lateral adjustment of the Mirror Attachment plate w.r.t. the Collimation Support to enable centration of the mirror in the tube.