My project: This is the finished product, I did not take a picture before, but this looks just the same only it stands upright now.
This is a compost barrel. We throw in our grass clippings, and banana peels, a other organic waste in it to make soil. We can spin the barrel to mix things up, and let it rot. The frame is all made of solid plastic 2x4s. The uprights are bolted with 1/2 inch bolts to the base. One long threaded rod goes through the middle as an axle to rotate on. The uprights started to fail after several years of use. The plastic 2x4s were getting oval holes and one cracked.
I made some super duper oversized "washers" or reinforcement plates to hold everything solid again. I tried to get 3 inch wide aluminum bars, but the only place that had them was a 25 mile each way trip. So I went with the 2 inch bars which I suspect is plenty big. I cut them 9 inches tall, (it was a 36 inch long bar) and drilled the two 1/2 inch holes to align with the current base.
I then epoxied the bars in place to the plastic 2x4s and then used three self tapping screws per bar to hold them in place as well. I only have one vice to clamp one and clamps to clamp the other one.
The photo just above shows the 1/2 inch bolts in place only to align the plates with the plastic 2x4s to get clamped in place.
This is just the base. One of the uprights had cracked, which allowed the upright to lean forward enough it was off center and the entire rig fell over with a full load of compost in the barrel. I had to empty it before I could repair it.
The plates are solid and should hold it steady for many years. As you can see, there are casters on the rig as well. The rig was designed to just stay in one place. My wife decided it should have wheels. She bought some wheels that were wimpy and broke in no time. So I added some pressure treated 2x4s to the base, and some steel plates to attach bigger and stronger wheels to. She could give rides on the thing around the block now, but it gets moved a few inches at most so far.