Typically bond failures initially occur with a peel rather than a shear
failure. You might consider bonding the hinge to the cowl and installing a
rivet at each end to reduce the chance of peel failure where it's most
likely to start.

Install the rivets "wet" with adhesive and it's unlikely they will "work"
and become unsightly. While you may not care for the appearance, using a
non-flushhead rivet will produce a better joint. I'd recommend etching the
bonding surface of the aluminum hinge just prior to bonding.

If anyone is interested in an excellent reference book I recommend:

"Handbook of Adhesives and Sealants"
by Edward M. Petrie
ISBN 0-07-049888-1
published by McGraw-Hill

It's not cheap but it is incredibly complete and contains a lot of valuable
information.

Ted Stanley