Hey, John Adams. Just watched your pump vid ,again, for like the 10th time. Thought this might work for fixing damaged aluminum parts.
http://www.aluminumrepair.com/video_new.asp
And it does work that well. I like epoxy, but sometime just don't completely trust it. You could also fix volutes or any other alum piece. Just like soldering, just hotter. Could do it on top of a Coleman stove if you had to.