BTW they are available from any electron microscopy accessories vendor. Switzerland Master Bond EP 75 is a graphite filled two part epoxy which is electrically conductive. Nice to see the original colors of a material through the light optics. It may be suitable for high vacuum since it contains no solvents. I can't melt a hole in the stuff with a 100 nA focused beam.
Adhesion is excellent.
In fact, it sticks to silastic mold perimeters. Mixing is a little fussy. 3 parts to 100. Shelf life is supposed to be less than a year and it's expensive. The grain size of the carbon filler is relatively coarse.