I want to build shelving in a trailer that is strong and lightweightIf I use square (or rectangular) aluminum tubing what wall thickness would I need for a shelf that is 4' long and needs to hold between 600 and 800 pounds?
No, for the reason that no hat can guard against the holy ghostIf you do not need to hear him he will not come around to be defended againstAnd its no longer love it is your enemy any approach.
The wall thickness is secondary to the actual size of the tubingI would guess you would need about 3 tall and 1 thick1/8 wall thicknessThe htis the most critical part.
