Not another Quench Oil Post!!

[kbaknife]

Bear with me, but I think this needs to be consulted as well, and that's the importance of using "QUENCHING OIL" instead of other "stuff".
This is in light of the two other posts we've been talking about as far as "speed" in oils.
This is the phrase we've not discussed, which you might see in two different forms but both mean the same thing - vapor jacket or vapor barrier.
I'll bet some of you have seen mention of guys quenching in water, but in the same paragraph may have seen the word BRINE.
Brine is simply water with the addition of salt. The correct amount of salt added to the water is the amount necessary to float a raw egg.
By adding salt, what you have done is changed, what you might remember from High School chemistry class as, the Specific gravity. You have in essence dissolved salt into the water making it heavier and denser.
(That's why a raw egg will now sit on top of the water instead of sinking, because the water is now denser than the egg instead of the other way around.)
This might get a little drawn out, so hang in there.
As well, what you have done is RAISE the boiling temperature of the water. Because of the raise in density, the brine now needs to got hotter before the water can turn to steam/vapor.
This is what happens - to cool the steel, the quenchant must be in contact with the STEEL!! Right? The quenchant must be in physical CONTACT with the steel in order to absorb the heat from it.
But!! If you quench a hot blade in pure water which BOILS/VAPORIZES at 212 degrees, then all around the blade the water has turned into a vapor jacket! There is NO WATER TOUCHING THE STEEL!!! There's just a jacket of steam!!
So, in light of the two previous posts I made about the quenchant needing to be able to suck the heat out of the blade in just a few seconds, if the water is NOT touching the steel to suck the heat out, then the steel will revert to Pearlite and NOT Martensite.
So, we add salt! This inhibits the creation of vapor! As a result, the BRINE remains fluid and QUICKLY sucks the heat out of the blade. And in MANY cases, does it so well it can crack the steel.
Now, here's my point about using the CORRECT QUENCHANTS!
The big difference between proper steel quenching oils and IMPROPER oils like mineral oil, olive oil, transmission fluid, etc. is ADDITIVES!!!
Lets be plain here - cooking oils are designed to SELDOM go above about 400 degrees. But, we're talking about dropping in a piece of steel that's over 1450 degrees!!!!
The exact same thing happens to that cooking oil as what happened to the water without salt - VAPOR BARRIER!!!!
All around the blade, that oil gets sooooooooooo hot it just turns to vapor and NO COOLING IS TAKING PLACE!!!
The steel reverts to Pearlite.
That's where the steel industry smart guys come in!
For the large part, short of synthetic quenching oils, most quenchants are basically mineral oil. But the smart guys add "secret" additives that PREVENT VAPOR JACKETS!!
They put "stuff" in the oil that prevents vapor barriers and keeps the fluid in contact with the super hot steel so that quick cooling can take place.
Now, some guys use ATF and used motor oil, etc., etc.
Well, if automotive motors operated at a temp so hot that they GLOWED - you know, around 1500 degrees - the automotive industry would have placed ADDITIVES in the lubricants to keep them from turning into VAPOR. Because vapor would not be able to do the same job as fluid.
But, motors do NOT run that hot. So, those additives are not in the oils.
When you drop a 1500 degree piece of steel into some used motor oil, all around the steel, that oil has turned into vapor and no cooling is occurring. And that piece of steel just reverts back to pearlite, or some combination thereof.
I hope this helps to clarify some of the other posts going on right now.

[DANA HOLMAN]

Thanks Karl
That is very helpful, might i ask you what oil should i use for 1084 and 5160, i got my shippment in and need  to get the right oil now i do use 1095 some times, so can i use the same oil,
thanks for your time
dana

[kbaknife]

Sure - 5160 - Parks AAA.
1084/1095 Parks #50.

[DANA HOLMAN]

Thanks Karl

[prarieboy]

Thanks Karl But where do You you purchase this Parks #50? Thanks in advance Bob

[kbaknife]

Here's a copy of the post from the other thread:
If you are interested in purchasing Parks brand oil, contact this guys right here:
[email protected]
His name is Patriq something.
He has an on-going thread here:
 http://www.bladeforums.com/forums/showthread.php?t=569729
I don't know the guy and I gain nothing from this.
He sells both Parks #50 and Parks AAA.
You won't find quenching oil in your everyday hardware store.
I got the oils I need for a long time some years ago and am not too up-to-date on current suppliers.

[kbaknife]

And that's just one place to get quench oil.
You can buy quench oil from McMaster-Carr, or Brownelle's.

[gables]

Would the parks #50 work with the Cru Forge V?

[drewsbow]

Karl : I looked at McMaster Carr and they list a 28 second oil and an 11 second oil. Is the 28 considered medium or ? I didn't see any parks in my book for them. Thanks Drew

[kbaknife]

Originally posted by gables:
Would the parks #50 work with the Cru Forge V?

That is something I haven't played with, but from what I gathered from talking to the head metallurgist at Crucible steel, and one of the collaborators who helped spear head the research on CruForgeV, yes.
Absolutely do NOT warm up the oil but leave it as cool as you can.
Do you guys know that warm/hot oil cools steel FASTER than cool/cold oil?

[kbaknife]

Originally posted by drewsbow:
Karl : I looked at McMaster Carr and they list a 28 second oil and an 11 second oil. Is the 28 considered medium or ? I didn't see any parks in my book for them. Thanks Drew

I would think that the 28 second oil is considered slow oil and the 11 second oil is medium.
I can be way wrong on that. I haven't used any of their stuff so I don't know.
I would just call them up! Ask 'em which oil for shallow hardening steel and which for deep hardening.
You will only see Parks oil at Parks Metallurgical or being sold by the guy I've posted on here many times.
I don't have his email at hand, but it's on some of the other threads.

[Steve Nuckels]

Thanks Karl, you certainly convay some great information and take a great deal of your time explaining the "deep" information needed to be consistant and deliberate to make a peformance knife!

It's appriciated!

Merry Christmas!

Steve
-------
ABS Apprentice
Potomac Forge
-------
IN GOD WE TRUST

[ALW]

Just out of curiosity, what additives do they put in the oil to prevent the vapor barrier?  Or is that a trade secret?  Just wondering.

Aaron

[kbaknife]

Originally posted by ALW:
Just out of curiosity, what additives do they put in the oil to prevent the vapor barrier?  Or is that a trade secret?  Just wondering.

Aaron

I have no idea.
I just know the results.

[tomh]

I switched from Brownells tough quench to Mcmaster Carr 11 second. Same results for a fraction of the price. I will NEVER buy oil from brownells, after the raised the price to dang near $60 a gallon.
The Mcmaster stuff is 15 bucks a gallon, and for me has worked great on 1080, 1084, and 5160.

 I would like to get some parks at some point, as I really like how clean the knives come out, and the transition line on edge quenched blades is outstanding.,

but like Karl said, don't let it get warm. I cracked a big chopper, and the oil temp was 111 degrees. room temp is PLENTY fast,oops

to anyone wanting to use cheap oil, Mcmasters is the hot ticket. Same price as a gallon of vet mineral oil, and the difference in results will be night and day.

[Jeremy]

Warm oil cools steel faster than cold oil becuase as you warm the oil it's viscosity decreaes, aiding in the convective heat transfer.  That's also the reason why you'll get faster cooling when you thin mineral oil with a lighter oil or liquid.

You can search the patent data base and find compositions of a few of the quench oils.  They won't tell you exact amounts of the additives used, but give ranges.  Some of the listed additives could raise the specific heat of the mix considerably, but are thickeners and that effect is offset by additives that thin the mix.

[drewsbow]

Thanks Karl , good info. Drew