Methods of manufacturing mirrors

A method of manufacturing a mirror, the method comprising:

• obtaining a core structure made of a material that has a coefficient of thermal expansion equal to or less than 0.5 ppm/° C.;
• obtaining a faceplate made of a material that has a coefficient of thermal expansion equal to or less than 0.5 ppm/° C.;
• bonding the faceplate to the core structure using an adhesive formulation that includes:
• a binder comprising 40 to 60 weight % monoaluminum phosphate and 40 to 60 weight % water, the binder constituting 25 to 35 weight % of the adhesive formulation;
• a composition that includes a first set of particles having a coefficient of thermal expansion equal to or less than 0.05 ppm/° C. and diameters between 1 to 60 micrometers and a second set of particles having a coefficient of thermal expansion equal to or less than 0.05 ppm/° C. and diameters between 0.05 to 1 micrometers, the first set of particles constituting 80 to 85 weight % of the composition, the second set of particles constituting 15 to 20 weight % of the composition;
• the composition constituting 65 to 75 weigh % of the adhesive formulation:
• and
• curing the adhesive at a temperature in the range of 100 to 375° C.