So, I have 2 main issues: candle and ores. Candle has Cylinder base and Cylinder fuse. They both are welded and unanchored. Candle in this case goes crazy. Ores is almost the same - but it has one base rock, and mostly metalic ore bits welded to it. Ore bits are massless and welded. Ore jumps and flings away. You can see this behavior in this video.
Reproduction file with sample models.
PhysicsIssue.rbxl (66.5 KB)
Issues go away if I scale model up. But this’s not solution in my case.
Expected behavior
I expect them to work like needed - ores shouldn’t jump and candle is not rocket - it should just fall down and maybe roll.