How to Build a Rock Crusher
Using a trowel, pack the capped 6-inch iron pipe with wet cement. Quickly insert the 3-foot iron rod into the cement. Move it until it stands at the center of the pipe. You may have to prop it in place by fixing a C-clamp to it and laying the clamp on the top of the pipe. Let the cement dry -- even quick dry cement may take 4 to 6 hours to set.