Does Quench oil deteriorate?

[alexkuzn]

I'll be getting Chevron #70 oil. I don't do too many knifes so my oils will be just sitting in a garage and it gets pretty humid there. Will oil deteriorate overtime in these condition? How do I know if if it's not good anymore?

[mete]

I hope you have a cover for your quench tank , first for safety in case it flashes up. Second to keep out dirt etc when not being used. Oil isn't going to deteriorate much from just sitting there. The deterioration occurs when you take steel at 1500F and dunk it . That after all is above the flash point of the oil and it will break down,oxidize etc. But since you have a proper quench oil that's going to tak a long time !

[alexkuzn]

I won't be making more than 25 knife a year.
What do use for quench tank?

[Ed Caffrey]

I've goofed up ONCE with the quench tank and had to change out the oil. My tank has a 110V heating element installed which is what I preheat the oil with. One day I plugged it in, and got distracted (the Mrs. came home for lunch) I walked into the house with her and forgot the tank was plugged in. A little while later she said..."There's smoke coming out of the shop!" That's when I remembered! I had all the doors, including the overhead open because it was a warm day, and by the time I got there to unplug it you would have sworn that the place was burning down. I got darn lucky! I unplugged the tank and turned on the gable fans to clear out the smoke.

When it was cooled the oil was a dark brown color, and after testing it it just would not cool blades down enough to harden them. I dumped the tank and then refilled it with new oil.

Aside from stupid mistakes like that, the oil will last a VERY LONG time. Of course the level will go down a little as you quench blades, and you may have to add more, but I doubt you will "wear out" the oil with the number of blades your talking about.

I use vet. grade mineral oil that I can purchase at the local farm/ranch stores. Actual quenching oil is available here, but only is you purchase it in 55 gal drums at $20+ per gallon. The mineral oil is about $9 per gallon and I can purchase it as I need it.

My tank is nothing more than mild steel that I welded up. 1/4" thick walls. My main quench tank holds abut 3 1/2 gallons of oil. is 5" deep X 8" wide X 20" long.