Larry C. who posts here often made an alumininum strongback like your suggesting . Check the archives for his email I am sure he can answer your questions

Tom

BTW I never thought of a microlam beam that is a great idea. I made an MDF boxbeam this time. Was real straight but I would rather not have to glue up something. I was definatley hard for me to get everything clamped up true. There really is no need to have a perfectly straight beam though. You align most of the forms independantly of it. The important part is getting the end forms aligned correctly to each other. then the other forms can be adjusted. I say go with the microlam. Cheaper easier to attach to. A bit less "cool" but its just a beam.

: After pricing aluminum for a strongback on my current project, I retreated to
: steel. A 2"x2"x16' chunk of square steel tube with 3/16"
: wall thickness was $50 +/-. The best price I could find for sluminum was
: $4/lb., and anything suitably rigid would have been well over $100.
: Besides being cheaper, this tube is stout enough to hold up a house.

: The mold blocks are 1"x1"x3/16" angle iron, bolted down with
: 2"x5/16" square U-bolts (sounds like an oxymoron, but that's
: what the hardware guys call 'em), so they're easily adjustable, easily
: scalable for different boats and/or station spacing, and stout enough to
: use for a ladder. I'll try to get a picture up soon.