I know I said "thickened epoxy", and we'll get there, but first it is a good idea to inject clear un-thickened epoxy into each hole. By doing this you allow the less viscous, resin only, without thickener, to penetrate the surface pores of the core. this creates a better and stronger final bond.
In order to do this I inject straight epoxy into each hole with a syringe. I then let it sit in each hole for about 3-4 minutes and suck it back out with the syringe and squirt it back into the container where I add Cabosil to thicken it.