Ed, Two things to tell you. The metal pipe sounds like a good idea, and easier than what I am about to tell you. My cousin's neighbor kept getting his mailbox run down, so one day he went out, set up forms for a cement post about a foot or so square and the proper height for a mailbox. So he had a solid concrete post. No one ran over his mailbox after that.
Second thing. When I ripped out the old deck in my yard, the 4X4 posts had been set in the traditional way. Dig a hole, stand the post up, dump in dry concrete, and pour water in. When I removed the deck, all I needed to do was wack the hell out of the 4X4 posts at the bottom, with a sledge hammer and for the most part, the concrete broke apart in several chunks. I just had to dig them up and pull them out in nice big pieces. No jack hammering was necessary. so, you may want to try a few good wacks with a sledge before renting a jack hammer. although, it is a good excuse for playing with a jack hammer. -- Blue skies. Dan Rossi Carnegie Mellon University. E-Mail: d...@andrew.cmu.edu Tel: (412) 268-9081