What oil should I use for quenching?

[Gorō]

On 24/07/2015 at 1:14 AM, Charles R. Stevens said:

canola oil, olive oil, bacon greas, lard, tallow or comertial quenching oil, stay away from used motor oil. I dont oersonaly recomend ATF or hydrolic oil either. 

Whats wrong with used motor oil? Can I use used motor oil for tempering since it has a high flash point??

[Charles R. Stevens]

It's nasty stuff, not only are their heavy metals in it from the babit barings, their are all kinds of odd organic chemicals (either intentional or results of thermal breakdown) it is recommended one wear as a minimum rubber gloves wile handling it because of potential cancer risk (ex mechanic) do you really want to breath the vapors?   

[Sparta]

I am a beginner and I have read through most of the threads. From what I gathered, is that I should stay away from used motor oil. That is what I was planning on using. I have seen that people use various oils, such as canola, veggie, and oils from fast foods. To start with I am going to use scrap metal around the farm. Is there an oil that works for all kinds of steel? From the threads I have looked at I did not see a ratios or percentages on the oil. Am I missing something or is there a better place to find my information?

The link from Mr. Sells didn't work for me. So I have tried to looking.

[SLAG]

Sparta,

Where are you located?

I recommend peanut oil to quench.

Peanut oil has a very high flash point. (i.e. temperature where it catches fire). Ask any Chinese chef. Used cooking peanut oil will work.

You can slow down the oxidizing of that oil by putting the oil in an air tight container after use. Putting several capsules of vitamin into the oil will also slow down oxidation. (it is an anti-oxidant). Also keep it out of the light when you store it. And keep it cool.

Another benefit is that the smithy smells like a kitchen when you use it.

Welcome to the forum.

SLAG.

[Sparta]

I live in the middle of nowhere in Minnesota.

I am limited on getting peanut oil. It is about 45 miles to get to a town over 10,000 and a Chinese restaurant. With that being said, I don't mind traveling if I have to, I want to do everything right the first time, I would like to hear other options before jumping on a bandwagon and rolling with it.

I am looking to start with small buck knives out of scrap material as I said. Material such a old knives from a stock chopper, old parts, ect. So I wouldn't need a whole lot of oil but enough to get me by while I figure my own way of doing things.

All other hints and tips are welcomed. I would prefer to do my own research, so any other places to look would be great!

Thanks for your time

[Steve Sells]

what link of mine didnt work ? post it I will repair it if I can find it

[JHCC]

The flash point of canola oil is only 40 degrees below that of peanut oil, and most grocery stores carry it at a reasonable price. 

[SLAG]

Sparta,

A grocery store should stock peanut oil. Forget about Chinese restaurants. If not canola (rapeseed) oil will work almost as well. And corn oil will work too. If none are available than cooking oil is O.K.

Hammer man you scooped me by about half a minute.

Regards,

SLAG.

[ThomasPowers]

Next time you go to town to buy groceries; buy a gallon of the cheapest vegetable oil they have.  (If the store cooks food ask them about used oil...  If there is a restaurant in town ask them about used oil.)  Peanut oil is better but not required! (I usually stock up on peanut oil after thanksgiving when the folks that fried their turkeys are going to throw it away) Don't forget to pre-heat the oil before quenching.

The county next to mine has only 3725 people in it and is the largest County in NM by area...6929 square miles.  So we understand issues with availability (and compared to folks liking in Hawaii or Iceland or Alaska---we've got it *good*!)

[Sparta]

I am waiting for my propane tank to arrive so I can get to work. Haven't gone to town to see what is in stock but I will keep you posted to see how it goes.

I do have one question. Do I need to preheat the oil before quenching? Or is room temp ok?

 

Here is the link that I could not get to work. It was under the beginners heat treating section.  

https://www.iforgeiron.com/url]

 

Thanks again for all the info. Again all tips are welcome!

[Frosty]

Welcome aboard Sparta glad to have you. It was hinted at but I find being more direct is usually better. If you'll put your general location in the header you might be surprised how any Iforge folk live within visiting distance. Telling us in one post isn't going to stick in anybody's memory longer than it takes to read the next post or open another thread.

As a beginning do't worry about trying to find the best quench oil, I get mine from the local supermarket deli. I keep asking for the used donut fry oil but keep getting oil that smells of chicken, fish sticks, egg rolls, etc. I bring a clean plastic jug with my name written in Sharpy and a tag with the request for a fill up when they change fryer oil. They have to change oil at least once a week but our local Safeway gets a LOT of traffic, lunch and dinner are long waits. Chat them up a little, tell them what you do and why you want the oil. Remember to ask when they usually change oil and check back on the day. You don't want them tripping over doing you a favor.

How is your quench tank set up? Do you have a fire suppression system and plans for an emergency? I keep my oil in a 15 gl. grease barrel with a steel lid and it's in a cut down 55gl. drum again with a steel lid. If I were to get a boil over and fire I can toss the lids on ad leave the shop till the smoke clears.

Put your fire extinguishers near the exits! Hanging one over or even next to the thing that might catch fire is a BAD idea, it makes perfect sense but is still a BAD IDEA! You do not want to have to reach through the flames to get a fire extinguisher. Worse you don't to have to stand outside ad watch your shop burn to the ground because you couldn't get to a fire extinguisher during the narrow, sometimes VERY NARROW widow of time when you can put a fire out before it really gets rolling.

Frosty The Lucky.

[ThomasPowers]

Warmed vegetable oil gives a faster quench than cold oil due to the lower viscosity. 140 degF has been suggested but don't overheat it!  I had a student who thought if warm oil was good then *HOT* oil would be better.  He never thought about quenching his blade in oil that was hotter than his intended tempering temp... I went out and bought a scientific thermometer just for him to use on the quench tank...

[Sparta]

I used the peanut oil and did good for the file test. I haven't been aggressive with the knife at all. It looks ugly but it will cut nice. I wouldn't say it is a terrible knife. Functionally it will work fine. As I said, I am using scrap metal for now until I find my groove then buy steel to make a more purdy knife.