8 in. x 48 in. Concrete Form Tube

A:  I assume your question refers to an application for which it was not intended, i.e. the sleeve being a post ... no concrete used. If that's the case, and a generous portion of the sleeve is exposed, I would say that it couldn't support much for very long because these tubes are wildly irregular in shape and construction and deteriorate when exposed to the weather. For example. ... if I placed a 50-lb disc across the top of one of these tubes, and the tube stood unsupported, in a matter of weeks if not days, I would expect there to be sufficient asymmetric loading on the sidewalls to cause the load to topple.

A:  We do not have any information to how much weight a concrete form tube would support

A:  It's difficult to say if this would be a viable way of creating one form tube for the purpose of pouring concrete into. It would likely be best to use one tube at the desired length for pouring concrete.

A:  Yes, if the tape is waterproof. Else, the joint is going to break as soon as it gets wet.

A:  If Being used in ground yes. If your using it above grade then no. 

A:  Here's the theoretical answer: One 60-lb bag of concrete mix will fill a volume of 0.45 cubic feet One 80-lb bag of concrete mix will fill a volume of 0.60 cubic feet The volume of an 8" diam x 4 ft long tube is 1.39 cubic feet A 4x4" is actually 3.5"x3.5". If the 4x4 extends the full length of the tube, its volume will occupy 0.34 cubic feet of the tube's 1.39 cubic feet; thus, you only need enough concrete mix to fill the remaining 1.05 cubic feet. And that can be done 140 lbs of concrete mix [in this case one 60-lb bag plus one 80-lb bag]. And that can be done with

A:  To pour an 8" x 48" form tube including the 4 x 4 post will take approximately 3/80lbs. bags of concrete mix.

A:  We are not aware of depth required for your project. With that said. The Form Tubes can be cut to a specific length.