Ron,
I've had poor results with FletchTite Platinum and Duco on aluminum as well, even when I've slightly roughed up the shaft surface with very fine sandpaper and cleaned it with denatured alcohol or acetone. Especially if the feathers got damp-- then some of the feathers would lift off fairly easily after a little more shooting.
I now use Bohning fletch tape on aluminum, and it works great. I put a drop of Duco at the front and back of feather. I haven't had a feather come off yet with fletch tape.
The suggestion above about using a drop of super glue at the front and back of the taped feather may be a better idea than Duco (I'd use super glue gel-- it's thicker). I've found that the Duco doesn't really bond all that well to the shaft, and I sometimes have to cut/scrape the dot of Duco off the front of the feather and redo it because it's lifted off the shaft.