Thanks for the advice

I'm a winemaker by trade so access to 304 and 316 is supremely easy. I understood that drawn tubing lost its work hardening if heated sufficiently, or do you have to get it all the way to the recrystallisation temperature for that to happen? I'll be brazing not welding and with 56% silver I should be able to keep it below 700C or so.

I can get 410 tubing here but I need to order in quantities of >600m. Not going to happen in this lifetime. Basically in Australia at the moment if it's used in mining you can get hold of it, if not, hard luck. Melbourne used to be the manufacturing centre of Australia but Guangzhou is now.

If you can get 410 tubing at surplus prices, want to make a quick few quid selling it to me at retail? I want 38.1 x 1.6, 31.8 x 1.6, 28.6 x 1.6 and 25.4 x 1.6 but I don't need much of any of them and the lengths can be short for easy shipping. A length of 5 x 50 flat bar would also come in handy.