How long does canola oil last?

[me2]

I'm wondering if anyone has an experience/experiment supported guideline for this.

I've been using canola for some years for a couple reasons, the main one being that I imagine that it's somewhat less toxic than petroleum oils (or maybe toxic in a different way )
There's often a caveat when experienced bladesmiths (L. Thomas, Cashen) mention canola- that it becomes unpredictable and breaks down over time.
My question, is there any kind of guideline other than guesses, as to when to replace it?
I'm asking y'all to do my homework for me, it's true, but as in so many cases, it's likely someone already has, and I just don't know where to find the results.
Thanks!

What steel are you using? The first knife I heat treated was O1 steel in olive oil. We had a hardness tester at work and the steel hardened to 65 HRc. However the hardenability of O1 is quite good and I would not try a steel with lower hardenability in any plant based oil quench. Q

 

[elementfe]

Once again, thanks for all the good ideas!
It's interesting how two points of view can both be true- Yes, Larrin, absolutely- anybody in this craft should make a point of really understanding proper heat treat norms and steel behaviours. Also, if you're using a specific steel (52100) for a specific line of cutting tools and getting the results you need, perhaps it's the "right" quenchant for the reasons that Alex gave.

Your results on 1084/canola are concerning, for sure, and my conclusion is that I need to do more of my own testing and use Parks until then.

However, Cashen did say (looking for the quote) that he had gotten good test results but that as the canola broke down it became unreliable- my question was whether anyone had quantified that variable, and it looks like that's going to be my job.