question on quench oils

gibsonfan you really like jerking me around all over the place dont you lol. :D
i guess ill goto the dollar store and buy a large amount of cooking oil. i guess canola it is. my town doesnt have a wally world. just one grocery store, 2 liquor stores and half a dozen bars. not to mention the dollar store. ill pick up a gallon next time im there or wait til i go see mom and stop off at wally world on the way. anything else i need to get while im there?
 
GibsonFan said:
On the other other hand, I have access to 5-gallon pails of new 90W gear oil (not synthetic) at work... do you guys have any comments on using that?
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My initial thought (unsubstattiated, gut feeling) is that 90wt would just be too high viscocity. One of the reasons that we heat the oil up is to reduce viscocity in order to promote the flow of oil over the surface when we quench. A high viscocity oil will basically vaporise a small amount of itself just around the blade which will create a vapor barrier around the steel. Since it's thicker oil though, replacement oil won't flow back in quickly enough to continue cooling at the rate you need. Thin oils with a high flash point are your friends when playing the quenchant roulette game.

-d
 
Allan Molstad said:
In that case,,,I would wiggle the blade while I quench,,,
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While it's pretty easy to think that might solve the problem, the truth of the matter is that the quenchat "flow" we're talking about here is during the first VERY short portion of the quench (the "vapor phase"), and the flows being discussed are problems with microscopic fluid dynamics. If my supposition above is correct, you can test it very easily with veggie oil or similar.

Take 2 identical pieces of a simple hypereutectoid steel (1095/W1/W2/etc) and quench one in cold oil and one in oil warmed to 130-150F. See which gets harder (you may need a rockwell tester or test files to properly quantify this...). Move the cold oil quenched one around all you want while quenching, it still won't get as hard.

Moving a blade around during quench promotes a much larger scale flow that serves to move quenchant that has absorbed all of the heat it can away from the blade and get cooler oil in contact. This is more helpful to bring the blade the rest of the way down towards Ms. The real work of a quench (especially with simple high carbon steels) happens in less than the first second (and the vapor phase lasts a lot less time than that).

I'd suggest taking a look at Kevin Cashen's thread on how to read a transformation curve chart (Huh...when did that get un-stickeyed?). It will help make sense of what's happening inside the steel during HT.

-d
 
sounds good. yall are making me run even lower on budget. yall are so mean to us n00bs of knife making. HEHEHE!!!!! now i need to find even more money or start singing on the street corner just to pay for a couple more items. i know i will need canola oil.

deker - thanks for that advice. helps me understand it a bit better.
 
go to the local chippie shop and beg the old oil from their fryer. the old oil from home fried chips was plenty good enough for me :P just run it through a sive into the quench chamber, get all the BCB's (burnt crunchy bits) out first.
 
Jacob, if money is real tight try calling some restaurants or greasy spoons around you (maybe those bars have a kitchen) and perhaps see about getting their used cooking oil. They should even be able to tell you just what type of veggie oil it is. Otherwise, if there is a Sams Club near you can buy about four gallons of veggie oil for about 12-15 dollars. Another idea for oil fires is to keep buckets of sand around as well as your other fire control measures to dump on an out of control fire if need be.
 
deker said:
My initial thought (unsubstattiated, gut feeling) is that 90wt would just be too high viscocity.
-d
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OK, so it likely wouldn't cool the steel fast enough. That makes sense, thank you. I think the vaporization you're talking about is called the Leidenfrost Effect... high school was a long time ago, lol...

I forgot about the sand bucket idea, thanks for reminding us Guy.
 
I just tried 4 gallons of ford tractor SAE 90 100% mineral oil transmission-or is it gear oil? plus one gallon of shell rotella 15/40. Got the shell oil cause TSC only had the 2 mineral oil jugs and I wanted to make 5 gallons. Quenched 4 blades-It works really well- file wouldn't bite at all...I think the flame ups would not have happened if I had left the shell oil out. Comments?
 
That Other Guy said:
I think the flame ups would not have happened if I had left the shell oil out. Comments?
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The flame ups are the fun part....
Without the flame ups, my wife would not think I'm crazy.

The flame ups also scare my guests to my shop as I never tell them that it's going to happen.

It's happens to me all the time, and I have come to enjoy the out-of control nature that a fire brings to my life.
In fact, if I dont get a flame up I begin to question if I'm doing the quench right?
 
I have a question. Can I put used olive oil in my Subaru? Oh, no, I meant can I cook my french fries in automatic transmission fluid? Oh, no, I meant....

Of course I am being somewhat facetious, but you get the idea. Different oils are made to do different things. Yes, you "can" use all sorts of oils for all sorts of purposes for which they are not designed. The real question is do you want to? If you want to, then go for it.

John
 
PimpinSquee said:
im sure i still have enough cash left over to buy some canola oil and maybe some steel.
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If you are not going to buy the real thing, I would suggest you use a steel that doesn't need the fast quench that the 10XX steels require. O1 might be a good choice-it's relatively cheap and easy to heat treat, although it does needs a short soak.
 
thanks for the info. i might as well pull a little bit more money from my savings stash to buy some actual HT quench oil and also some steel. if im lucky there are a few places in san antonio that might sell knife making steels.
 
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