screwy idea for tempering

[jdm61]

Here is a thought. Since the tempering range for 5160 in theory can be below the smoke/flash point of a fair number of oils, could you possible simulate the effect of low temp salts.....can't remember if it is aus- or martempering....... by putting your 5160 blade in say, oh, a deep fryer at 350? assuming you could put the fire out with a lid and get the temp back down quickly ...lol

 

[mete]

Yes it can be done but having a big container of oil just below the flash point is not the safest thing !!!

 

[fitzo]

Max Burnett did just that a few years back with some success. Don't remember the specifics, sorry, other than it turned out pretty acceptable results.

 

[jdm61]

I know it is not safe, but when is sticking a piece of steel at 1500F into oil ever safe? Thats why i forge in my gargage and am building a concrete blcok shop...lol I have a BIG 19 inch roasting pan with a tight fitting lid that i am going to use as a quench tank. I have a cheapo Hamilton Beach fryer and i was thinking about taking the heating element off and using it to heat the tank. No way it would ever get the big pan to 350-375, but it should get it to 150 or so. I am going to use the cheap bare wire thermocouple that came free with my Omega handheld for the oil temp. It is good to about 800 or so. I was just thinking about using the actual fryer at higher temps for small 5160 blades to see what could be wrung out of them. I can't do it for W2 because you can't get the oil to 450 where it needs to be to temper W2 down to 59-60 RC.

 

[JCaswell]

I think you're referring to Austempering or Marquenching (both use 'low' temperature salts).
Why not just use salts? A lot safer than the boiling oil and the results are very dependable.

 

[jdm61]

salts require a tank setup which costs more money and requires more space than I have right now.

 

[argel55]

Joe I have seen where a person used the fryer pan itself. 1 1/2 inches of oil in the fryer to temper with . Seemed to work for him- even set his quenching oil in the middle in a steel tube then dropped it into fryer to keep at that temp for 1/2 hour.

 

[Bruce Bump]

salts require a tank setup which costs more money and requires more space than I have right now.

The nitre blue salts are very safe and affordable. I use a simple propane camp stove and a cheap tank. I hear that stainless steel tanks will work. If you want to experiment with marquenching I think you should put out the bucks otherwise just do the old quench and temper method.

 

[Kevin R. Cashen]

You know I went against my better judgement and wrote another of my long boring tomes but thought better of it since I doubt I really addressed the concerns of this thread and quite honestly I am tired of being a punching bag for daring to question whether any liquid a person can get their hands on is automatically a winner for advanced quenching techniques, so...

...SNIP.....

...Everybody is entitled to learn from their own trial and error, if they can, so let's just say I agree with mete, JCaswell and Bruce.

 

[delbert ealy]

I would go visit your local hospitals severe burn ward and take a good look at someone with 3rd degree burns. after that you do what you want.
Del

 

[fitzo]

I feel sort of guilty, after all these negative comments, that I mentioned Max had tried this some time back.

Commercial martempering oils are certainly available. The concept is viable, if done properly.

Appropriate is always a different question. I figured since Joe called the idea "screwy", he knew he was telling the truth.

 

[butcher_block]

You know I went against my better judgement and wrote another of my long boring tomes but thought better of it since I doubt I really addressed the concerns of this thread and quite honestly I am tired of being a punching bag for daring to question whether any liquid a person can get their hands on is automatically a winner for advanced quenching techniques, so...

...SNIP.....

...Everybody is entitled to learn from their own trial and error, if they can, so let's just say I agree with mete, JCaswell and Bruce.

dam you and your long winded....
...snip...
.....end rant
hahaha
btw i like reading the long posts im so smert that it only takes me a day or so to read and a week or so to think i understand
nice one i too thought about tring something like this but thought a little longer and went with not good

 

[indian george]

Now I tried this and it's a screwy idea. I filled up a Neso Oven with sand and ash and brought it up to 375 deg. It took 6 hours to get to 375.

 

[jdm61]

If you guys think that the nitre blue salts won't eat up an enamel coated steel pan on the first try then we might have a winner here and one more thang........Rant away. Mr. C........we who have developed nothing in the way of theory, practice or sacred cows of any other ilk find them most informative:thumbup: I screw up aenough blades actually trying to follow tried and true methods.........I can scarcely imagine how badly I would do in the "trial and error" arena...lol With that said, i am guessing that my idea has met with a resounding "not no but F**K NO!!!!!!!!!!! LOL

 

[GibsonFan]

Now I tried this and it's a screwy idea. I filled up a Neso Oven with sand and ash and brought it up to 375 deg. It took 6 hours to get to 375.

Well that would be a lot safer, yes? What if you heated up some "scrap" to help the sand temp along?

 

[Kevin R. Cashen]

I have been reflecting on questions and answers that I am often involved in here, in other writings and in person, and I think there tends to be a lot of miscommunication right from the onset. I think we may need to be more attentive to the goals of the one seeking advice before jumping into suggested solutions. “Can I use XXXX for a quench?” I immediately go for whatever it takes to maximize the potential of the steel and the resulting properties without considering where a maker wants to go with it. Do they want to cut rope like a fiend? Do they want to chop oak kindling all day? Do they want to be able to bend it in a “U” with their bare hands in order to scoop out a bowl and then easily bend it straight to cut some salad for that bowl, or do they wish to drive it into a tree and use it for a step to climb? Not everybody gets into aviation with the goal of breaking the sound barrier or going into space, some folks look forward to having a ball with experimental aircraft at more leisurely speeds over the treetops.

Perhaps “good enough” can be good enough? If you go for a 4 minute mile, only make it in 4:50 and your friend comforts you that 4:50 is actually damned good and gets you to be satisfied with your best, some would call them a good supportive friend, others would call them an enabler holding you to mediocrity.

Fine pearlite is the bladesmiths best friend/enabler. You shoot for maximum hardness and potential in a quench, you get at knife that skates a file, is tough and will even break like it is fully martensitic. You feel you have achieved success because your friend, fine pearlite, has given you that impression. A friend indeed, fine pearlite is always there for you, even when you don’t know it. You may snub it while spending 80% of your time with martensite, but fine pearlite will still stand by you and tag along the other 20%. When your edge should wrinkle up and dull, fine pearlite will be there to save your dignity and carry you through. It is a friend that will dress up like a martensitic chauffer and drive you to the party so that you can appear to be a real 65HRC guy and hang around with the other successful martensites. If you honestly decide that you are happy with this arrangement then fine pearlite is your friend. If actual success is what you need then fine pearlite is deceiving you.

Some folks can get their needs met by this arrangement, and will say that substitute tools and improvised solutions work just fine for them and give them the results they need. But what are their needs? Perhaps I need to consider that because to me fine pearlite is a lying rat always trying to trying to hold me back and come between me and my best buddy Mr. Marten Site, and is not welcome in my shop. I insist on truth and honesty in my friendships and when I have failed Mr. Marten Site will tell me I blew it and to do it right or quit wasting his time.

P.S. mete should love this! Just when he thought I couldn’t get stranger I manage to use a John Hughes movie plot as a metallurgical metaphor .

P.S.S and before anybody tries to pick at the fact that the guy finds happiness with the fake chauffer in that movie- if that girl had any self respect she would have told the twit to cart his tart around himself and stick the chauffeur’s hat up his backside after he removed his head from it and figured out what he really wanted.

 

[JCaswell]

P.S. mete should love this! Just when he thought I couldn’t get stranger I manage to use a John Hughes movie plot as a metallurgical metaphor .

I haven't seen the movie to which you refer, but the metaphor stands on its own. Entertaining and poignant.

 

[fitzo]

When I first saw this thread, I was excited about the possibility of discussing the implications of what Joe was suggesting. I thought there was more to learn there than just whether stuffing a 1500 blade in hot oil had hazards.

Just a few years ago it would have led to an inquiry about what happened when one quenched to hold the piece below Ms and above Mf for an extended period, a known industry technique. Effect on microstructure would be mentioned. Questions like, "How long to hold?", "Does it 'self-temper'?", "Does a quench to Mf still need to happen?", "Are subsequent tempering cycles necessary?", would have arisen.

And the most important, "Is it of benefit in making a knife?"

Back the last time, the experimenter reported he "liked the blade because of performance tests." Now we have the benefit of guys better informed (Kevin and mete and RJ) who can explain what happens technically. One of 'em has the equipment and curiosity that suggests he might even have done this and have the data to share. We all have a chance to learn. There's nothing wrong with extending the topic in a thread beyond the simple answer to the original question. That would mean that someone who doesn't know the right questions is destined to remain uninformed. That leaves them in a Catch22: "Well, unless you know the right questions I can't tell you anything"

I'm all for taking these opportunities when they present themselves. Go beyond the immediate topic. If the technique makes fine pearlite, Kevin, then say so, please, without the abstruse metaphor I don't understand! Reinstate that "longwinded response" you elected to delete, please! Thank you!

 

[Kevin R. Cashen]

Fitzo, it is a weekend but believe it or not I have not had a drop to drink . Perhaps I am working on getting more poetic instead of so technical. You are doing fine and I have no opposing position to offer your posts at this time. I would hesitate to take Max to task in public on too much since not only is he a friend, he was one of my students . I also like to keep myself well rounded, I have read Shakespeare, but have also perused the National Enquirer, I have copies of Citizen Kane and The Godfather but I also check out cheesy and obscure 1980's brat pack flick occasionally .

Not beating the curve with simpler steels results in fine pearlite. Fine pearlite is not the soft stuff that we are used to with coarse pearlite and it hides nestled amidst martensite packets. Quenching to Ms and then holding to equalize is a legitimate technique, it had better be since I use it with every blade I treat. Pearlite does not form at these temps anyhow; it precipitates around 1000F and above. The technique is sound just some tools to achieve it are not optimum.

The whole reason I am dancing all around this issue is because I am a minority among bladesmiths on this topic, and dozens would beg to differ that you can heat up any old oil you like and not get the same results as those elitist overpriced martempering products. They have their evidence and test results and I have mine, only I also got the same results at one time and then found some other ways of analyzing things.

In light of this I am trying not to present this as a right or wrong type of thing, because I am realizing that some folks simply have different definitions of what a knife should do. So many things that I would never do "work fine" for others because they simply have different goals and criteria for their knives. I am convinced that an astounding number of handmade knives out there are good enough because fine pearlite does not behave in the way that we expect coarse pearlite to, because of the number of techniques I see that are good recipes for making fine pearlite. But the question I am really posing here is "is that necessarily wrong?"

If one can do everything they expect from a knife loaded with fine pearlite, is that not good enough? For myself, I can emphatically say, "absolutely not!" but can I say that for others?

I can go on swimming against the tide for the next 20 years or I can just take time to ask if the person wants the most martensite possible or do they just want to be able to make a knife that can cut a rope X amount of times and then bend to 90 degrees? Because a discussion of this nature will inevitably produce a post from somebody eager to say “it works fine for me”, and working within their parameters it does, working within mine it does not. Who is correct? Among the points that I consider to draw my frame of reference is the fact that I know of no serious industrial application (ones with a heck of a lot more on the line than a wrinkled bowie knife edge), where hot peanut oil is the medium of choice for martempering. But the custom knife industry is very different from any other steel working field, now isn’t it?

My experience with this has shown me that one cannot expect to see a glaringly substandard blade by quenching simple steels into 400F Crisco, in fact I expect to be surprised at how well the thing actually does cut after I get it under the microscope and see things that make me want to wash my hands after touching it.

I am really rambling on today

 

[fitzo]

Thank you for the explanation, Kevin.

As you have read, I am a technical geek and argue for that approach over poetry. (Though I do admit to reading "The Jabberwocky" today after thinking about "Vorpal" blades. )

As you state, it can get discouraging arguing against, "It works for me." If someone CHOOSES to get what they do out of knowledge, then that is much different, though, than caveman ignorance that just says "Don't tell me the facts, I have a right to my opinion." Ignorant is not a position.

A few months back, I was discouraged and told someone I respect about that. They told me, "Don't quit speaking up; if you do then ignorance wins." It wouldn't be right to say who it was, but you know the guy. It made a difference to me.

Thanks, again. You give food for thought, as usual. Which is why you shouldn't be deleting too much. :thumbup: