Published 11 issues of fanzine Worlds Beyond (October 1978-September 1980) in Dunedin, New Zealand. Other fanzines include Fission Chips (four issues 1981-1982), Godzilla's Dental Floss (two issues 1986 and 1987) and as editor of the National Association for Science Fiction clubzine Warp (issue 41, December 1984). One-off fanzines included Can't Think of a Name So We Called It This (1982).
Cardy was official editor of New Zealand apa Aotearapa from March 1980 until November 1983. He joined Aotearapa from its first mailing in November 1979 until November 1999, contributing numerous apazines. He also contributed a one-off apazine to Aotearapa in July 2007.
Cardy was secretary of the NASF Dunedin branch in 1979 and was part of the con committee for Octacon in 1982 - the first New Zealand national science fiction convention to be held in Dunedin. He was FFANZ winner in 1983.