Just to add on to that, the rivets may not hold up well against higher pressures (unless they are sealed), but for this application, they are plenty watertight as long as they are installed correctly. As far as the rivets go, keeping it really simple, you will want to use universal aka "button head" solid aluminum rivets. We have been using -5 (5/32) and -6 (6/32 (3/16)) rivets and so far have not needed anything else. You will want a couple different lengths of each size rivets, for instance, we have 5-4, 5-5, 5-6, 6-5, and 6-6 (lengths are in 1/16ths of an inch) to allow for different grip depths (material thicknesses) i.e. extrusion to extrusion or extrusion to hull. As a very generalized rule, for the rivet sizes we are working with, you will want the rivet to protrude through the hole about 1/8" (too short won't be as strong and too long with lay over when hammered). The rule for how much to compress the "shop head" of the rivet is Finished Diameter= 1.5*Original diameter (this can really just be eyeballed). So once you get it all setup, hammer 'em out. make sure to apply equal pressure on the the rivet gun and the bucking bar so as not to deform your base material.
WEAR SAFETY GLASSES AND HEARING PROTECTION (IT IS EXTREMELY LOUD!!!)
Tools:
air compressor and hose
drill: battery/corded/air (reversible air drills are very convenient and i picked one up for $15 at harbor freight)
air hammer("rivet gun") - $10 harbor freight
Rivet sets (punches)- picked up a set of 5 (3/32,4/32,5/32,/6/32,countersunk) for about $18 on Amazon
Bucking bar - $15 Amazon
Rivets- you will probably have to order them online (i couldn't find them anywhere else)
layout & fitting tools - speed square, clamps, vice grips, tape, etc....
well that was alot longer than i originally planned, guess i got carried away. hope this helps somebody build up the courage to try it.