Hey Bama, nice rig you put together. Ive been running numbers on the various diameters with various frame setups similar to yours, and found that 1 1/4" sch 40 IPS weighs .786 a foot and the 1" sch 40 weighs .581 a foot. The sch 10 1 1/2" IPS weighs .721 lb/lf.
You are correct, the strength (section modulus) of 1 1/2" sch 10 is slightly more than 1 1/4" sch 40. I wasnt able to find the section modulus of the 1" sch 40, but the 1" appears to be strong enough if braced at shorter lengths, so the 1" should have the weight advantage.
But I dont see how your frame can stay at 38 pounds. It appears that your frame has 4 upper and lower rails x 7', 4 cross rails x 5', and 10 verticals and other short pieces x .75'; which gives about 56 lf of pipe. Multiply by .721 and I get just over 40 pounds. Add 20 fittings at a minimum of .5 pounds each, plus 4 pounds for the towers and locks, and I get 54 pounds. The short seat is almost 5 pounds. Am I missing something?
I have an NRS style frame with their drop rails not too much different than yours (I think Mania has the same setup), and about the same dimensions and fittings, which weighs about 75 pounds with seat and locks. The NRS fittings are certainly heavier. Thats why Im trying to lighten my load. Mania if you're out there, have you weighed yours?
Even the sch 40 1" IPS 1.31" OD size only gets a no frills frame with triple welded yokes down to what I calculate as about 48 pounds, using 12 Hollaender tees at 13 ounces each.
Still thinking about the frames from ID and OR, and getting a way to get one down to CO. Thanks for the input from everybody..