Changed my mind about coolant concentration after a chat with an old timer

I always ran my coolant at 10% because that's what the manual said, but last week a retired machinist named Harold watched me change a tool and asked why my parts looked dull. He showed me his old parts from the 80s that still had a factory finish because he ran 8% with a drop of dish soap to break surface tension. Has anyone else experimented with tweaking concentration outside the book spec?

2 comments

2 Comments

jesse_burns822d ago

Betting that dish soap trick carries some risk though.

david12322d ago

Harold knew his stuff, that's for sure. The dish soap trick is one of those old school things that works because coolant is designed to cool and lubricate, not always to wet the part evenly. I've run 8% on aluminum for years with no corrosion issues, though I would not drop below that on steel where rust is a bigger concern. The soap lowers surface tension so the coolant gets into the cut better, but you have to watch your tramp oil levels since soap can mess with your skimmer. @jesse_burns8 is right to be cautious. If you try this, start with a fresh sump and keep an eye on pH for the first week.