John,
If you look at it technically, ali is a very difficult material to 'stick' together. It forms it's own oxide coating in a matter of seconds after the original oxide layer is penetrated, it is for that reason it has fairly good corrosion resistance.
What's all this crap got to do with it sticking together?
Unless you coat the whole joint surface with superglue, the joint will most probably be very weak and won't last that long. The oxide layer that the glue is stuck to will just break away from the surface and a new oxide layer will be formed on the surface. Resulting in a very weak bond.
Stew has the right idea, and the one I use most of the time. Using double sided tape over both full surfaces will give a longer lasting and stronger bond. But don't use it if you are going to do any thru drilling, as the joint will most probably fail as you penetrate from one plate to the next.
John