Been a long time since I steam bent anything, I like your light duty steam box...LOL
We had a section of 16" galvanized road culvert about 10' long back home for a steam box used mostly for bending boat ribs on the cape islanders we built and repaired then. Bent ash for skies and runners but mostly larch ( hackmatac) for boat ribs. 4-6 hours of steaming they were really limp but they were quite green to start with, planed to one inch thickness by 2.5" wide in most cases for boats under 30' long.
We had a section of 16" galvanized road culvert about 10' long back home for a steam box used mostly for bending boat ribs on the cape islanders we built and repaired then. Bent ash for skies and runners but mostly larch ( hackmatac) for boat ribs. 4-6 hours of steaming they were really limp but they were quite green to start with, planed to one inch thickness by 2.5" wide in most cases for boats under 30' long.