On 4/3/2021 10:38 PM, Linda Iverson wrote:
What if I just want to use black steel pipe as a curtain rod to hang heavy velvet drapes spanning a window greater than 12 feet long without the need for a center support? Ill anchor ends using flanges (nipples and elbows) screwed into solid wooden header above window. Seems like it should be more than strong enough for such a girly thing.


"Strong enough"? It depends - it will be strong enough to not fall
down, but it will sag. How much sag depends upon the weight of the
"heavy velvet drapes" & the diameter of the pipe. If you specify the
weight & the maximum sag acceptable, someone here can tell you the pipe
size to use. However, heavy drapes and a 12' span mean that the sag
will probably be unacceptable for anything but a really big pipe.