On 2008-04-09, Speedy Jim wrote:

Surely not cast iron. Galv steel pipe?

Yes, cast iron.

One has to ask, why not PVC?

Cast iron is quieter and this is above a basement that I may wish to
finish in the future.

Have you considered the slope of the pipe? Over a 25' run, the
pitch will eat up 6" of the joist depth. Add the pipe O.D. to
that......

Yes, indeed, it just works. The pipe OD is 2.5" and the fall is
6.25", which makes 8.75". I have old 2x10 joists which are 9.5" deep.
So it all fits. I will need to make a larger than usual hole in the
subfloor to accomodate the long turn 90 at the upper end.

Mostly I'm just looking for an expandable bar support, I'd prefer that
over plumber's tape.

Cheers, Wayne