I decided now was a good time to closeout the upper horizontal VS rib beneath the rudder horn. I need this done in preparation to close out the vertical area once the tip is riveted back on. I taped up the conduit, then jammed a small piece of high density closed cell foam up front (between the conduit and VOR mounting block) to limit the spread, then filled most of the space with polystyrene foam cut to size on the bandsaw, then poured in epoxy and microlight in the gap between the styrofoam and rivet heads to key the part in place (I don't want this to potentially come loose and jam the rudder). After a while I popped all the bubbles to make it easier to seal after sanding flush with the upper edge of the skins.