CB Slot Cap - Foam stuffed in to provide some upward pressure for the *fit*

First, lay equal layers of masking tape on both sides of it, so that it barely fits in without getting stuck (this approximates an equal buildup of final sealing epoxy on both sides of the structure). Then stuff some foam in on top of the CB, just enough so that this mount can be pushed into it, and yet rises slightly above the top when released. The foam will hold tension from below while two small spots of 5 minute epoxy cure and spot weld the piece in perfect alignment.