been screwing around getting this done.....and it's still not, but closer than it was. there has been a few of "these" threads lately, which as helped get me moving. material is 1x1x0.125 and 1x2x0.125" alum box tubing. not sure what type, it was just what ever was laying around, but i think it's 6XXX series. brackets were aquired from altrec, tho they needed cut down ahelln. not overly impressed by them, they don't look like they would be very sturdy but they are, for now anyway. it turned out alittle more low profile then i was planing on, apparently i dropped a half inch somewhere in the math, but it's all good. there's almost no deflection in it......even when i stand on it. zero noticable wind noise. still have a few odds and ends on it, mostly some cosmetic things and a couple functional items. main purpose is canoe and kayak transportion....with a secondary of looking cool.