Hi Steve,

For bonding CF pieces together we found and Mike Jones concured that JB Weld worked very well and is available to us amatuers

A thin bead on the edge of the tube and then carefully place it the position on the flat plate that you require.

After it has set up, lightly sand the exposed JB Weld and then using a tiny spatula, run a filet of JB Weld around the tube to the plate for added strength.

As far as the CTE goes, if your mirror is pyrex your are at about 2.0 x 10 -6 in/in F

Aluminum is 12.3
304 SS 9.6
410 SS 5.5
plate glass 5.0
porcelian 2.5
Wood Fir 2.1
Silicon 1.7
Invar 0.8

And then CF can be designed anywhere between Negative 0.3-0.5 to around 2.0, but it is not easy for us amatuers.

As to an RTV with the same CTE of Pyrex, no way...they are closer to 20+ typically.

Thus, if it were me I'd be looking at something with the smallest differance for the temperature that I would be using the instrument. ie, you are not likely to be using it at 90 deg F. and more likely to be using it at 40-70 deg F.

Thus, what ever you chose look to do you bonding at the middle of the temperature range of your use without getting into dewing problems during the cure of the silicone to the substrates.

I'd personally go with CF at 90 +45 90 -45 ply with about 8 to 10 plys ending up with the top and botton in the same orientation.

Clean both CF plate and mirror back with acetone and then alcohol, and bond them together.

Any further questions, just ask.

Best Regards,

Preston