Just read a study from a machine tool magazine that said 80% of shops run their coolant too rich. I always thought more was better for tool life. Anyone else check their mix with a refractometer regularly?
Yeah, I was surprised by that too when I first started checking. I use a cheap refractometer every Monday morning now. Found out I was running at like 12% when 8% was plenty for my aluminum work. What concentration are you aiming for?
That study lines up with what I've seen. More coolant isn't always better and can actually cause issues like residue and skin irritation. A refractometer is the only way to know for sure what you're running.
That point about residue really stuck with me. I read a forum post where a guy kept getting a white film on his parts, and it turned out he was just mixing his coolant way too strong. A simple refractometer check fixed it.