Long and short of it. My bathtub’s spring stopper has deteriorated. Building manager solution was to use a rubber stopper. I looked for a replacement part, couldn’t find one outside of an outright replacement. So I modelled and printed this one in TPU.

It works!

EDIT: 2h30m later, the I’ve lost ~20mm of water in the replacements tub. Probably should increase the width of the Part to get a better seal. Nothing I can do about it tonight

EDIT: 12h later, the tub was pretty much empty. Trying again with a wider plug since I think the fit wasn’t tight enough before. As for those who think a regular stopper would be better, you are right. But for the $0.16 of material and a learning opportunity for TPU I don’t see it as a waste of time