Originally Posted by
Bushmiller
Brisso
I am not convinced that steam bending would be an option with some of those tight curves with any solid timber. Laminating is almost certainly the way to go and as others have suggested, keep the laminations as thin as you can as it will be so much easier to work with and I believe there will be less tendency to spring back with thinner material: Consequentially less guesswork. Depending on what machinery you have available I would go less than 2mm if I could, but certainly not more.
Years ago I made a spiral staircase and the handrail was from laminated strips of Ironbark about 5mm thick (about ten of them). I would glue it up and clamp on the form using resorcinol glue (the two part stuff that looks like strawberry jam) and remove the clamps the next day. Then I would test the integrity of the join by dropping it on the ground whereupon it would spring apart like the components of an old fashioned watch. 5mm was much, much too thick. Not knowing any better in those days I gave up and used some radiata pine that I stained red.: A poor substitute.
That staircase was nowhere near as tight as your poang chair with a diameter of 1.5m. I know Silky Oak (assuming Grevillia Robusta here) is not in the same strength category as Ironbark, but those radii are a really big ask of any timber.
I would also cut some test pieces from the Silky Oak to see whether they can be bent that tight at 90degs. You will very quickly know if it is on or not.
Regards
Paul