[DMF_TomB]

Never ending story I'm sure, but I'm thinking about switching coolants. CNC milling mostly aluminum and plastics.

I get a fair amount of tramp oil, but my coolant is suppose to reject it, or so the info says. It seems like the coolant separates and I sometimes end up with almost dirty looking water with very little lubricity.

Each morning there is a varnish type coating on the vises and table surfaces. When the varnish dries I can only remove it by spraying coolant on it. I use a syphon type mixer. The product is Monroe Astro-Cut HD. When it's new it's great, but it losses the greatness in about three months.

Anyway, what are you using and do you like it? What does it do well and what could it do better?

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on a mill i just use plain mineral oil for milling aluminum. the same used to lubricate the machine. it leaves a oily residue that is not sticky and prevents rust and wipes off easily. worst case i use alcohol soaked baby wipes to get last 0.1% off a part. i use plain oil on a lathe too. radical concept but my machines are never sticky or have a tar like residue on them. stay rust free and wipe off easily. coolant never smells or has concentration problems.