No affordable Electrical Metallic Tubing (EMT) in Australia; PVC is used for electrical conduits.
Down the rabbit hole we go:
1.2 - 1.6mm wall thickness recommended (.049″-.065″)
Stainless is recommended but slightly overkill. Steel works well, only concern might be bearings could leave marks in the surface of the round bar over time. You can simply rotate round bar to compensate. Square tube or rectangular half section (RHS) as we call it is not recommended.
304 grade stainless is for general use.
316 grade stainless is for marine use, offers excellent rust protection in salt climate and is slightly more expensive.
Chromium in both 304 and 316 offers rust protection. Molybdenum in 316 offers additional resistance against chlorides and chlorinated solutions. Hardness is same between 304 and 316. 1 inch stainless round bar is often used in outdoor railing.
https://www.australwright.com.au/products/stainless-steel/stainless-steel-tubing-tube-fittings/
AW As Welded
AWP As Welded, Polished
AWA As Welded, Annealed
AWAP As Welded, Annealed, Polished
CW Cold Worked
CWP Cold Worked, Polished
Round tube 320 grit finish standard, 400 grit for 316 only on request.
Common polishing finishes: satin, mirror or milled (not polished)
https://www.blackwoods.com.au/part/06333810/tube-ss-rnd-ann-316-254mm-odx16wtx6m
- Grade 316
- 25.4mm (1 inch) outer diameter (OD)
- 1.6mm wall thickness
- Manufacturer Austral Wright (product code 50008000)
- AWP, 320 grit polished, satin finish(?)
- 6 meter length
- $90.90 AUD per length ($65 USD)