When you pour concrete footings, hold the cardboard concrete form tube about 12 in. up from the bottom of the footing. Do this by nailing the sides of the tube to the center of a tic-tac-toe grid ...

Essentially it’s a cardboard tube, a plastic nosecone ... cardboard tubes can be tricky to ship without getting crushed, [Concrete Dog] has come up with HEXA, a clever model rocket kit that ...