i need to find highway 6 by 6 guard rail, because i want to build an island in the lake bed in my back yard that i will have a zip line go out too from my second story deck over the water and onto the island, but the lake freezes in the winter so i need at least 6 by 6 steel posts so i don't have to take it out ever and would never have to replace like wood pileings, seems they don't sell fucking highway garud rail anywhere, yet i see it all around me on the highway