Well, the MC3 left primary and secondary prisms sat in another acetone bath all day - the secondary (metal) prism finally fell off, but the primary looks to be well bonded to the barrel of the optic still.  Degradation of the glue joint usually occurs at some vulnerability in the boundary of the bond (like where some glue has chipped away or at an irregular area like a bubble or crack which then lets the liquid seep in more efficiently.  We could see this happen on the secondary, but the primary doesn't show any such areas.  We have even used a razor blade to strip away excess glue and look for soft spots in the joint edge.  No luck today.  More soaking tomorrow.  Of course this debond-rebonding project is time critical so I shouldn't expect it to go well.

Thanks Gerardo for all the prism-sitting.