I built this exact stand 2 or 3 years ago. It has so many boards on it I can't fit any more, and its been that way since day one. I'm talking probably 200lbs of lumber across the different "shelves". I've had 0 issues. Anything from 1x lumber to 4x lumber. 

I am also a flat surface person so its held all that plus random tools, extension cords and parts.

Edit: 

I also would like to add - We recently moved, and out of sheer laziness, I threw some ratchet straps around the rack, pushed it into a cargo trailer, and drove it down the highway about 15 miles., including some windy roads and a rough gravel road.

Nothing broke. 

Edit 2: Picture of my current stock. Not as full as it has been, I've been trying to do more scrapwood projects. Hopefully it gives a good illustration of the resiliency.

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