Hey, so it turns out PLA can survive a trip through a pressure cooker at 15 psi. Are you thinking what I'm thinking? Just add a length of 1/8" (3.18 mm) music wire and seal with temperature tolerant silicone sealant or gasket maker, and you have yourself a stir bar for a DIY magnetic stir plate.
I use these for home mushroom cultivation. So far, I haven't seen any inhibition of mycelium growth or spore germination.
mag_stir_bar_tube_v2.stl | 744.1KB |