Hi all again, been a while since I have been on here. Can anyone give me a little advise on what I am going to make will take the weight load?. At the rear of my camper I am going to weld a 4x2" 3mm thick steel box section from one side of the chassis rail to the other, I then want to weld 3 of the same 4x2" box section to make a sort of platform to hold a metal storage box, the picture I have made is not the best but you can see what I mean by that. I want to know if the size of metal box section and arms where they are welded will take a weight of around 80kg? Thanks for looking and any replies Ian.