Here's mine, basic concrete filled ballast with some barbell weights placed inside. I'm guessing around 700 lbs =/-, not completely sure. I wish I had a crane scale to weigh it to know the exact weight.
if you like doing math you could probably get a pretty close estimate. you can tell how much steel you had weight wise, and also the volume based on the size of the weights and bars used. figure the overall volume of the box, subtract the volume of the steel, and that is the concrete volume. figure 135 lb/ft3 for concrete and 490 lb/ft3 for steel/iron.
I've removed the pipes, added more weight and topped it off with a manhole cover. 800#?
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