: I have been considering a 2 X 4 strongback made of plywood, a 2 X 4
: inch aluminum extrusion and schedule 40 plastic pipe.

...

: I have heard of people using schedule 40 drain pipe (4"?) as a
: strongback. It would seem to be a good idea. It is quite ridgid,
: VERY cheap (less than $10 for a 10 ft section). I am not sure
: the best way to attach the forms, but it does not seem like it
: would be a big deal. The 4 inch sched. 40 is a little over 4
: inches in diameter and would require some modification to the
: strongback dimensions in any plans I bought. If anyone used
: schedule 40 as a strongback, I would be interested in their
: thoughts on how it was modified to attache the forms and stem
: pieces, if 3 or 4 inch was used and any other feedback.

I haven't. But I'd imagine it might get tricky at the ends, where things get pretty narrow. You might have to use quite long maybe 3' long end forms. In nicks book he suggests that he'd use PVC but only for up to about 14' I think.

Cheers Ian