My friend wants to put a 12 foot metal box-tube across two decks, and hang a swing off of itIt's for young kids who weight about 60 pounds , so I figure with the force of them swinging the structure would have to support at least twice thatHe's looking at metal fabricators but they all want him to just chose a measurementHe doesn't want overkill because it's not cheap and he doesn't want to have to drill into a thicker piece of metal than he needs to.Any ideas? The tubing would be aluminum.
Overkill is pretty standard practice in architecture and civil engineering when lives are at stake and cost is not particularly relevantIf you are making a thousand swings, it might be a big dealBut for one swing, why be cheap? The moment he turns his back, two or three 60-pound kids will try to swing from it at the same timeOr, what's cheaper, a 12' length of 3 galvanized pipe, or a trip to the emergency room? I would consider just using a 4x4You could stain it to match the decks, too.
