Saw a thread on another forum where a few people had the exact same problem with their new mix. They said the binder ratio was off, which made the sand too brittle. Makes sense if you're getting more scrap like that. Switching back seems like the right call until they fix the formula.
So which forum was that thread on? Were they seeing the brittle sand problem mostly with bigger cores, or was it breaking down even in simple molds? Kinda important to know what exactly to watch out for if it's a bad batch going around.
Yeah, the binder ratio being off sounds about right. Reminds me of the time I tried to mix my own leveling compound to save a buck. Let's just say the floor had more waves than the ocean, you know?