What i did for a ballast box is made mine......I took a 36" sona tube and put in a cross bar horz. and flat bar vertical so that i could weld pins for my 3point connections. I then fill it with 10 bags of concrete with each bag being a 80lb bag. with the metal that i put into the concrete to add internal support....i have about a 850lb ballast box that i can pick up as needed and sit aside out of my way when not needed.