My last mold attempt failed with a bad plaster pour. I got some new plaster and was able to pour V2 of my sphere mold. If you're interested in trying Shape Cast, my mold system, sign up at shapecastmolds.com
That's a good thought! In practice I havent had too much issue with these unless I try and reuse the mold multiple times. And in that case, it's just as likely that the insert fails. However even then, there are way more inserts/bolts than needed it seems because missing a few doesn't have a noticeable impact. I'd also thought about switching from M3 to something a bit bigger since I more or less picked at random and I'm not sure what tradeoffs there might be. I think in an ideal world, getting rid of the inserts would open the door for more people (at the potential cost of stripping out threads directly in the PLA).
using big screws for plastic might be an option. take a look at mc master's pn 90380A388 . they've a pitch of 2.24mm, 11 layers in regular 3d printing, so the thread formed by the screw should outlast the mold itself
