Mike, Thanks for the all-important clue that 'Tufnell' is a plastic. The correct name is Tufnol. The wrong name was posted on the page. Tufnell once worked in Abilene at the Long Branch. Tufnol is a proprietary name for a product of the Tufnol Corp in Glasgow. The stuff is supposed to have excellent electrical and thermal properties. Maybe someone knows more about its properties. My research is ongoing. Thanks again for the clue. Ralph Zekelman