> I am curious why you are seeking alternatives to a wooden strongback?

> If you are willing to spend $20 at the most you can get a really nice
> straight grained 2x4 at a lumber store (you can even get it in a stronger,
> more stable wood like oak if that is what you want).

> Or, you can buy a nice sheet of birch (or other) plywood and make a box
> beam that is incredibly strong and stable.

> Seems that the ease of use of wood along with the ease of fastening things
> to it with common tools would make it ideal.

> Just my opinion - I'd be happy to hear why I should change it!

Pete, I searched high and low for a 18' 2x4. All I could find was 16'. Birch plywood around here is $50 a sheet. Cheaper plywood is not worth bring home. So I found a 2x4, 3/16"wall structural aluminum extrusion. It is dead straight (by eye) and I just cut one of my tapers last night with a jig saw and it cuts about as easy as wood. I would rather wood but The aluminum cost was the same as plywood and it was already built and straight. I may live to regret my choice but right now I like it.

Larry C.