ricky_arthur
Well-Known Member
In all the discussions about quenchants, Motor oil is inevitably thrown into the discussion because, well, that is what some people have available to use. But the suggestion is always "USED" motor oil. Now, I do not use Motor oil but I do use Canola oil. I run a restaurant and have access to tons of "used"canola oil, but I have been using New Canola oil, Just because I can get it fairly cheap.
My question is this... Is there something about the oil; Motor or Canola that makes USED oil a better quenchant than new? Or is it simply a cost issue?
Also Wondering.
Heating the oil doesn't reduce the rate of cooling, It increases it. The thinner viscosity causes it to cool faster. In fact, the only reason I could find for keeping the oil temperature below 150 is because it begins to break down the oil and no one wants to shorten the life of expensive oil for a diminishing return. Even that reason makes little sense since the Canola oil I use spends and entire week about 10 hours a day at 350deg before it needs to be changed. I can't imagine that an hour at say 200 degrees would have enough of an effect to be worried about.
If oil at 130-150 degrees quenches faster than oil at room temperature, Then is oil at 175-200 degrees not going to cool it even faster? In my head it would seem so. (But I have never tested the idea, I always quench at 130-140 because I was told to do so)
To make sure my original question is being understood.
People always use the word "USED" oil when referring to using motor oil as a quenchant. Do they specify "Used" because it is better? or because it is cheaper?
If it is because it is better, Then could the same apply to non-petroleum oils? Is a used oil a better quenchant than a new one? I did a google search and couldn't find an answer to either question.
I'm simply asking because I have access to alot of both new and used Canola oil. I Have used both and with the simple methods available to me to test the results I can see no measurable difference. That most definitly doesn't mean there ISN"T a difference, only that I would be unable to tell a difference of say 1 or 2 or maybe 3 HRC difference. But if useing one over the other would RESULT in a few points HRC difference I would like to use the best of what is available to me.
Anyone have any answers to these questions?
Used VS New oil
125-150 Degree quenchant VS 150-200+ ?
Thanks
My question is this... Is there something about the oil; Motor or Canola that makes USED oil a better quenchant than new? Or is it simply a cost issue?
Also Wondering.
Heating the oil doesn't reduce the rate of cooling, It increases it. The thinner viscosity causes it to cool faster. In fact, the only reason I could find for keeping the oil temperature below 150 is because it begins to break down the oil and no one wants to shorten the life of expensive oil for a diminishing return. Even that reason makes little sense since the Canola oil I use spends and entire week about 10 hours a day at 350deg before it needs to be changed. I can't imagine that an hour at say 200 degrees would have enough of an effect to be worried about.
If oil at 130-150 degrees quenches faster than oil at room temperature, Then is oil at 175-200 degrees not going to cool it even faster? In my head it would seem so. (But I have never tested the idea, I always quench at 130-140 because I was told to do so)
To make sure my original question is being understood.
People always use the word "USED" oil when referring to using motor oil as a quenchant. Do they specify "Used" because it is better? or because it is cheaper?
If it is because it is better, Then could the same apply to non-petroleum oils? Is a used oil a better quenchant than a new one? I did a google search and couldn't find an answer to either question.
I'm simply asking because I have access to alot of both new and used Canola oil. I Have used both and with the simple methods available to me to test the results I can see no measurable difference. That most definitly doesn't mean there ISN"T a difference, only that I would be unable to tell a difference of say 1 or 2 or maybe 3 HRC difference. But if useing one over the other would RESULT in a few points HRC difference I would like to use the best of what is available to me.
Anyone have any answers to these questions?
Used VS New oil
125-150 Degree quenchant VS 150-200+ ?
Thanks