So there is actually just the inner reactor tube made of alumina, and maybe the sealing cement. The cap, ribs, and even the plug are made of Durapot.
This conflicts with what Rossi has maintained over time, and reiterated today, that "the larger drums at the ends of the cylinder" (i.e., what you are calling the caps I believe), are the only part of the device made of Durapot. I could easily see how a miscommunication between T. Dameron and Dewey could have occurred. For example (hypothetical), "Yes Dewey, I made those things out of Durapot using my own hands, and look, I even still have some of it left right here" (without necessarily pointing out which specific things). Rossi talks with confidence about the materials used, and the analysis at a renown university backs him up. Remember, in times past, when there has been a discrepancy in a public battle between Rossi and Dewey (e.g., temperature data), remarkably, Rossi has turned out to be right.
March 10, 2017 at 8:25 AM
The reactor tested in the Lugano experiment was made by pure Alumina. We used Durapox to make the two caps ( the larger drums at the ends of the cylinder of the reactor ), but these drums did not contain any charge: they just contained the cablings of the terminals. The thermocamera was focused only on the cylinder of the reactor, made by pure alumina, not on the lateral caps, made by Durapox. By the way: the material the cylinder was made of has been analyzed by the Professors and resulted to be pure Alumina, as reported.