Greg,
How about a phenol plate bonded in to the tank. Then turn a bung with a
flange sufficient to seal and bolt to the plate. Tap the bung, install
the fitting. If it should ever stip out replace the bung and retap.

Did this as a repair on a poly tank in my jeep. Trouble free for two
years now. (without the phenol panel tho).


All the best
Sean Trost

Greg Reid wrote:
I'm looking for tips on a proven, lightweight, leak-free, and
long-life installation of threaded brass fittings into my composite
fuel tanks. I have the typical fuel finger strainers, fuel sump, and
other threaded hardware to install. The strainer and sump may need to
be removed and reinstalled on occasion.

The obvious way is to use 1/4-inch or thicker phenolic, drilled and
tapped for the hardware. Scuffed phenolic would certainly give a nice
permanent bond with the epoxy, but I've heard that some folks who have
gone this route have had trouble later with the threads stripping in
the phenolic.

Another builder suggested that I use a 1/4-inch brass strip. I'm not
sure how well brass will bond with epoxy, and it's awfully heavy.

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.

Titanium, magnesium, other? Of course if metal, it has to be
compatible with brass.

Thanks,
Greg