I have a application that I need to seal wires with connectors in a 1/2 inch slab. Is the Alumilite conductive and if so how much?

Yes, Alumilite resins will have some insulative properties but not as much as our silicones (QuickSet works well for potting). Silicones will give you much more thermal insulation than urethanes however Alumilite resins will still act as a mild insulator. So much that the components will overheat ... I've never received information from any of our customers that this has caused them problems when potting PCBs with either our urethane resins or the QuickSet which is the typical silicone of choice for potting applications.