sword heat treating

Kevin McGovern said:
That's not a problem. Having the oil heated to 400 is the problem.
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Quenching into oil at 400 is worse than just heating oil to 400 and putting a room temp blade in it, IMO.

Once you've raised it so close to the flash point, quenching a 1500f blade just sounds like a disaster that makes salt pots sound like safety devices.

Now, if there are marquenching oils out there with super high flash points like Larrin suggested, OK.
 
kuraki said:
Quenching into oil at 400 is worse than just heating oil to 400 and putting a room temp blade in it, IMO.

Once you've raised it so close to the flash point, quenching a 1500f blade just sounds like a disaster that makes salt pots sound like safety devices.

Now, if there are marquenching oils out there with super high flash points like Larrin suggested, OK.
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Oh, I wasn't suggesting quenching into oil pre heated that high...
 
Kevin McGovern said:
Oh, I wasn't suggesting quenching into oil pre heated that high...
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I know, there's 2 conversations going on. Oil can be dangerous either way. Though it's likely easier to find a safe way for heating and holding the proper high flash point oil to 400f for normal tempering than for marquenching. I didn't even think there was such an oil out there. Or like Joe said, industrial controls.

Either way I'll save hot oil for my turkey personally. Well away from my buildings.
 
kuraki said:
I know, there's 2 conversations going on. Oil can be dangerous either way. Though it's likely easier to find a safe way for heating and holding the proper high flash point oil to 400f for normal tempering than for marquenching. I didn't even think there was such an oil out there. Or like Joe said, industrial controls.

Either way I'll save hot oil for my turkey personally. Well away from my buildings.
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This is true. The problem is that you are holding a oil near its flash point and simultaneously quenching an object far above it's flashpoint. Frying is safer because while you are near the flashpoint, you are not introducing anything to the oil that will bring it above said flash point. Also fryers are designed not to spill on the operator.
 
If you look at Larrin's link, you will see that the HIGH flash point Marquench oil has a flash point of 240C/536F. The other is even lower - 220C/460F.
Without industrial equipment including oil coolers and anti-flash gas shields a sword put in that oil would erupt in flames.

Anyone who has seen a Turkey fryer disaster video knows how bad a hot oil fire can get.

I'll be blunt - 99.9% of knifemaker's should NEVER consider quenching a blade in oil above 65C/150F.
It can burn your shop/house down. A garden hose won't put an oil fire out and a little shop fire extinguisher won't be much help either. It would also likely void your homeowners insurance... leaving you to pay the tab for a new house/shop.
 
Hi, I use 160C up to 180C oil for quenching ;) for 7 years. HTed more than 5000 knives - still have my workshop in one piece ;).

BUT yes when using hot oil be EXTREMELY carefull !!!! SAFETY FIRST.

Adam
 
Jamall,
I understand that you have made it work, but running a full time knife shop that turns out half a dozen finished knives a day is not the group of people we are talking to. On this forum thousands of novices and people using a weed burner for a forge will read these posts. They will try really foolish things if they see it in a forum or on You-Tube. Bladeforums Shop Talk tries to guide these folks safely.

We are trying to prevent an inexperienced person with low tech equipment doing something very dangerous. I will repeat -
Quenching a blade into 400F/180C oil is very dangerous and can cause a severe fire. If/when a fire starts ... it will be hard to put out. The likelihood of severe burns if it ignites is very good. Unless you run an industrial shop ... don't quench in hot oil!
 
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