I just called and got a cost on a "steel 2x4", 18' long, 25 guage steel. The cost was less than $4.00 and the guy said they had over 400 in stock.

They are the same size as your standard pine 2x4 but made of galvanized steel. They are easily cut with tin snips - to fit end forms on. Drywall screws bite into them like a wild dog.

They WILL NOT WARP - unless you sat on them, in which case you deserve what you get.

Can anyone think of a good reason why these would not work?

Also, how about homosote for forms material? It is "particle board" that is made of recycled newspaper. The paper is soaked until it is mush then heat and pressure is appled. It is sold in 4x8 sheets 1" thick and can be easily cut with a saber saw It is heavy, dense and should hold a staple well. It too would be very dimensionally stable. It's sold locally at Home Depot.

Thanks, Carl