How long does canola oil stay good for as a quenchant? I'm a newbie reusing the same gallon of oil with a little fresh added to top off each time, done 4 knives so far. Don't want to throw it out early, but don't want to waste propane and time having to re-heat treat either.
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How long can I keep using the same canola oil as quenchant?
- Thread starter milkbaby
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FOOORREEEEEEEVERRRRR....
In all seriousness, I'm not sure there's a "set" number of knives, but I think the bigger issue is that the oil tends to go rancid after a bit. I finally decided I really wasn't saving much (if any) money on the Canola and ordered a 5 gallon bucket of Parks 50. YMMV.
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- Jul 25, 2007
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Yes, any quenchant will degrade and one should never assume that a quenchant is working as expected. Degradation seems to always equate to a slower quench speed. You can find many scientific papers on the topic of quenchant degradation (for example http://qrc.fsb.hr/wp-content/uploads/effect-of-contamination-on-the-cooling-rate-of-quench-oils.pdf -- https://www.researchgate.net/profil...Quench_Oil/links/554b73e00cf29752ee7c7e71.pdf)
Essentially the quality of the quenchant is determined by measuring the quenching speed. Checking hardness after the quench would be the best approach (because it is checking almost every aspect of the HT process, including the quench speed).
Essentially the quality of the quenchant is determined by measuring the quenching speed. Checking hardness after the quench would be the best approach (because it is checking almost every aspect of the HT process, including the quench speed).