Yesterday, Margot and Nicole worked on cleaning the ITMy.
While working with them I noticed divots under the metal prisms that were glued on last week by Gerardo and I, in 2 places.  We believe these are due to differential thermal expansion coefficients induced during the (what we believed to have been) low temp heating from a heat lamp.  Shown in the attached picture is one of the divots ~6mm in size under on of the 4 prism "legs".  The other divot is on the other prism (not show) and is much smaller at just under 1mm in diameter.  The prisms are not loose.

After consult with the larger SUS team, 
1) Gluing of all SUS optic/metal components is being evaluated to maintain the bonding strength and outgassing requirements of the glue joints, while minimizing the differential thermal expansion issue seen here.

2) We decided to reinforce the existing joints under the remaining legs with more glue and cure at room temp.  The VRB is being consulted vacuum compatibility of this since the outgassing step will not be complete.

These bonds were cured at room temp for ~24 hours, then the heat lamp was turned on for an additional ~24 hours.

Note that the other 2 metal/optic bonds here at LHO were performed on the TCP and the ERM and were successful.  However, we followed a slightly different procedure which called for immediate heat lamp heat for 16-24 hours.  As well, the configuration of these bonds was also different in that the prism "feet" ran the full length of the prism so the bond was much larger.  We are investigation what parameters factor into these failed bonds, and assessing the actual temperatures seen from heat lamp heating.