Done this a few times, including on trailer DIY axle and the standard pop alum held up over a couple years there without issue. Also on a prior seatpost issue.
- TO THE GUYS WHO SAY BUY THE RIGHT SIZE SEATPOST there are manufacturers (AND OTHER APPLICATIONS) who don't think standards are for them.
Example - just bought a folding e-bike with 36mm seat post. It's also literally twice as long. It spans use from 5'2" TO 6'5" (157-196 cm) (FUNNY!) and (it says) is good to support 395 pounds (180 kg). Well - there you go. Now I want a suspender to go with my hard-tail - and the biggest they have is 31.6. Which means folding or layering that can - which I did before.
However I would also be willing to try thin sheet aluminium/aluminum from the hardware store - and some kinds of plastic sheet used for durability (thick heat pressed packaging keeps it's properties under extremes.)
I also discovered a handy source of stainless in just about that thickness (2mm/79 thou) - hidden inside just about any hanging file folder. I went to throw out a bunch and said - hey -- these would be like 40 US cents apiece. And not only that, but I THINK the folder material would be good for most stenciling apps since it's a hard all through and somewhat water resistant. Where else do you find 20x15 sheets of stencil blanks for free?
So yeah - I think you just cut a bunch and drop them in to make a circle - if it fits. Bend, solder, cut, done!