Oh man @thea_chen is right, I know someone who did the same thing. Honestly I had that exact same problem when I first started out. For months I was convinced more mixing time meant a better bond, but all I got was a ton of dry, crumbly sand that just fell apart in the flask. Tbh it wasn't until I watched a guy from an old foundry in Muncie show me his timer trick that it clicked for me. He said 'mix it til it's gray like a storm cloud, not black like asphalt' and that changed everything. Ngl I still catch myself wanting to go longer out of habit, but I force myself to stop at that two minute mark now. Saved me so many headaches with shrinkage and gas holes after that.

You mentioned "that trust you talk about is the whole ball game" and I see it differently. Trust is nice but it's not the whole game when it comes to tools. I've had a cheap ratchet that never broke and an expensive one that snapped on the third use. For me, it's more about knowing your gear's limits and using it accordingly, not just assuming it's trustworthy because you maintained it. Calibration schedules matter, sure, but some of us don't live near a service center and can't drop everything for yearly checks. So I work around that - maybe not ideal, but it's worked fine so far.