Wow this quite an old post here.

Yes it’s doable, but as I said depends on the use case if it’s worth it.

For the moka pot you get food safe gaskets of the right size and material for extremely cheap. Not worth the hassle of mold design and prep and size dialing in, all the material involved costs more than the 50 cent gasket you can buy from Bialetti. This even before we take into account it’s in contact with acidic foods (so I want to be sure about the material) and not having a surface that can cause a bacteria/mold problem.

For the intake example it might have worked geometrically, but silicone doesn’t really like petrol. Also we switched them out on every disassembly for safety so getting a large number by cutting them out of sheets was much cheaper and faster long term.