So heres the situation. Due to some unavoidable life situations this summer has been slow in my shop. Ok, lets be honest, I've barely cut anything this summer. Just a handful of cabs. And the 18" saw hasn't even been opened since late April. This week I got the bug to cut some rough so I went over to the 18" slab saw and opened it up. I looked down and thought "Damn, that oil looks dark!". So I grabbed a flashlight and shined it into the saw only to find that my oil had turned an amazing green color.
I've cut many different kinds of rock, and with the exception of psilomelane (don't ever cut that damn stuff until you are ready to change your oil) I have never had anything so dramatically effect the color of my oil. Even when I cut messy things like some red jaspers that stain everything the oil will always settle to a nice clear color when left to sit. In fact, my memory of the last time I looked into the saw the oil had settled clear. The mud at the bottom is still the usual brown muck you see in any slab saw that cuts a variety of different stones.
So of course when I see a bold green color like this I immediately think "copper". Then I remember that one of the things I picked up at Quartzsite in January was a big chink of Kingston Copper Ore and I slabbed it up in this saw in February. That ore is absolutely full of raw, natural copper. It makes dramatic slabs and cabs. But I know the oil did not turn green right away. Like I said, when it was last in use in April it still looked normal.
So my thinking is that somehow over the last few months as my saw sat in the summer heat of my garage some chemical reaction has taken place that dissolved the copper into the oil creating some sort of solution composed of mineral oil and copper. I dipped out some of the oil into a clear container to take pictures of it for you to see also. The color looks about the same under sunlight or my shop lights, and the pictures are pretty true to what the naked eye sees.
Now my question. I do not worry about this affecting any other stones I cut in it since I doubt this will discolor any other stones (although I might try a test run on some things that seem more porous just to see), but my main concern is could there be a health risk involved here? And has anyone else ever had such a thing happen to their oil before? Any thoughts you guys have would be appreciated.
SawOil by
Karl Camp, on Flickr
SawOil2 by
Karl Camp, on Flickr
SawOil3 by
Karl Camp, on Flickr