When evaluating the different ways to hold the primary mirror in place I found many different solutions. Some easier to implement than others and some more reliable than others. I finally opted by a combination of gluing while still allowing for a full collimation mechanism (for the primary).
Thanks to the sandwich technology, my primary is (will be…) only 12 Kg which is really light for mirror of this size. The back of the mirror is also flat as opposed to some with a conical shape to reduce weight and allow for a full gluing of the primary.
I designed a 18-point floating mirror cell which is articulated in 9 points using stainless steel spherical bearings (3 on the main triangular plate and 2 on the 3 arms). The primary will be glued in each of the 18 points. The exact locations of the 18 points was calculated by software.
The circumference of the primary is not held and does not need support for a light mirror of this size. For safety reasons, in case of an earthquake or car accident when driving the scope to its final destination, I added 6 studs all around the primary without touching it. To the front, a 17″ ID ring is fastened to the six studs and masks the edges of the mirror which completes the safety feature.