I do some bending with Guitars.... I wouldn't do it on PT wood for a couple reasons:
1. The wood is particularly low quality stuff -- knots everywhere... and knots and runout and cracks all split when you bend them...
2. Full of toxic chemicals like Arsenic... You don't want this stuff coming back out when you heat and boil it during bending....
3. It's generally some flavor of Green.... and shrinks all crazy, warps, twists, etc... enough as it is...
The general process for Heat bending wood is to get it hot and wet... then slowly bend it onto a form.... Wood 2x2 size would most likely take hydraulics to do this... not to mention some way to boil it under hot water for a couple hours... Pressure cooking it at 250-300F works better...
It is much easier with Laminated pieces -- the thinner they are (As in less than 1/10" thick) , the easier it is to bend them.... You still need to bend them over a form.. so each laminate would need its own form piece... or maybe you could bend the whole stack over a form, then let it dry a couple weeks.... then epoxy it all together.
There are woods that are easier to bend than others... Straight grained Quartersawn Oak is a traditional choice for Steam bending... Willow is also very compliant after you soak it in warm water for a few days.... Soft maple also works... The Key to these is that woods for bending really have to be perfectly straight grained with absolutely no knots, cracks, runout, or interesting figure to crack or split along... Quartersawn boards work really nicely for this....
There is also this stuff....
http://www.flutedbeams.com/ordercoldbendhardwood.html
It is Pricey! It is some sort of magical compressed wood that is shipped wet and bendy... then you bend it however you want and it dries back into its hard state.
Then, last is probably the easiest suggestion... Skip trying to steam bend thick stock... Joint up a bunch of pieces and just cut your arch out....
Tell us what you decide on.
John
