JB Weld FTW! I've heard of silver solder being used for steel bike frames [it melts at a lower temperature than normal soldering rod], but not for aluminum. Most Al gets TIG-welded. Actually, it would be very cool to CNC this whole thing. Precision machined insets for the LEDs and driver to mount into, inset screws holding things together, o-rings and gaskets... I'm sure somebody is already doing this.