Greg Reid asks;

Aluminum is another possibility and certainly lighter, but another
recent thread in this newsgroup cautions about the difficulty of
getting a permanent epoxy bond with aluminum.

Every composite canard aircraft out there uses aluminum hardpoints for
NPT threaded attachments into the tank, for the wing bolts, etc. I've
never heard of any of these (2000+ aircraft) leaking or failing.
Corroding, maybe, on one or two Vari-EZ's that live near the ocean, but
that's about it. The aluminum used for the tank drain mount points is
completely buried - only the threads get exposed, and only until the
fitting is screwed in.

Data's worth more than theory.

--
Marc J. Zeitlin
http://marc.zeitlin.home.comcast.net/
http://www.cozybuilders.org/
Copyright (c) 2004