6061 alum. weight question

[plinker]

I picked up an army antenna box at my local junkyard, it splits in half so I've got two "trays" to make into a tool cart.

The box halves are reinforced so they will hold the weight of my portable tool boxes pretty well I think.

I intend to get some aluminum angle to use to hold both trays together and to attach the casters to.

How thin can I go and still have the weight capicity I want? I can get 6061 alum. angle in 1/8", .187", or 1/4" thickness.
It's 1-1/4" x 1-1/4"x 3', FWIW

I'm leaning toward 1/8" as it's less money but would it hold up?
I'm guessing the top tray should hold 150-200lbs(I need to weigh my boxes I guess).

Here the alum. angle I'm looking at.
http://www.onlinemetals.com/merchant.cfm?pid=974&step=4&showunits=inches&id=62&top_cat=60

 

[GN4WHLN]

It is hard to say without seeing the design. However, I noticed the metal you selected is 6061-T6 which has the high yield strenth. Initally, it sounds good. Are you welding the structure together? If so, remember that the heat affected zone will have the temper reduced to T-0. The difference is that T-6 yields at 40ksi and T-0 yields at 8ksi so I would try to minimize welds around the greatest area of load. You might consider an X brace made from angle to stiffen your structure if it seems a little marginal when you load it.