Haven’t gone with an option yet, I called about stainless and it’s order in only too which means I can’t inspect it without laying money down first. Seems kinda dumb to trust that it hasn’t been bent in transit.
I did check my conduit out the back on the cement before I cut it down and bought it and it’s pretty true, nowhere close to 1mm. There were bad sections that were bent but I just cut around them. You’re lucky it’s in stock where you are, I’m on the Sunshine Coast and I’ve already bought the only two lengths I could find in stock :). I think the main issue I’m seeing is that my printed parts aren’t accurate and were way too tight so I had to use the joined part of the conduit to run on, clearly they weld the joins on the conduit I have and grind them, they are really bad.
I’ve chosen to get someone with a nice rostock to reprint my Z parts so I can avoid the join, I have one test inner middle part and it fits really nice, I should have the rest on Monday. I’ll let you know if I have any more progress with better tube as I’m still searching.
There does seem to be 25mm OD stainless and iron exhaust pipe in stock, I am yet to inspect a length to see if it’s suitable.