Also with an internal beam, once you have the forms on, it is
: not so easy to dismantle if you have to take the forms off and adjust. All
: will have to come off to get at the center one.
: Rod

Sure you can adjust things, and twists are really no problem as long as the wood is stable. You simply oversize your cutouts a little to compensate for these things.

As to having to take them all off to get at the center one? What do you need to get at it for? Even if your cutout is too small for the final alignment, reach in with a Japanese pull saw and 30 seconds later everything is A OK.

Oh, a note about my experience building a box beam out of 1/2 oriented strand board to build the 20' Guillemot Double. It was much flimsier than the 2x4, cost 3 times as much, took several nights to cut, glue and screw together, and when I was done the gosh darned thing had more curves in it than by great aunts back (or the worst 2x4 I could find at the local lumber yard). I put it to use with a couple of partial forms to hold the deck up to the rafters of the garage while I worked on the hull. I also had to resize all of my cutouts as I had desinged them for a tight fit as I thought a perfectly strait beam (HA HA) would eliminate having to do any alignments.

If money isn't an issue, but being straight and true is, use a steal or aluminum beam. What? too difficult to attatch stations? How about purchasing a laminated beam. They are very structurally sound and dimensionally stable and you can easily screw your stations to it.

Me? I'm on a budget. A 2x4 is the cheapest route and you can make it work.

Oh, as someone mentioned, fasten your stands to the floor. (This can also affect some of the external systems) One bump with your tow and the past two hours of alignment just went down the drain. (or in my case, 10 hours?) Oh its such a great learning experience!

Hmmmm. I think I will try an external strongback on the next project. They really should make alignment quicker. Oh, I have to build it first.....back to the 2x4 and get this puppy rolling.

Tom