Things you always wanted to know but were afraid to ask Kevin

Kevin...I need to know.......






What color smoking jacket should I wear, while wearing a fez?

Solid color....oriental design...?:D
 
If you liked that last question here's another one I got from a 1st grader.

One of the first jobs I had after graduating college was an "artist in residency" at a public school district. Most of the kids were asking things like, "How much money do you make?", and "Can I have a piece of coal?",... but this one kid asked, "Is bladesmithing important?"...

Now notice the question wasn't "was it important?",... it was "Is it important?" :)

I think he was looking for a simple yes or no answer... :D

A friend of the family got me the job, and it was very controversial. Most of the teachers thought it was dangerous and inappropriate for grade schoolers. Weird things happened back towards the end of the seventies. Luckily we got through it without any serious accidents... :)

One kid said, "I want to be a bladesmith when I grow up.",... bless his heart! :)
 
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Kevin R. Cashen said:
1084 and 1094 should not be quenched in mediums heated to 400F or better as they just will not cool fast enough to fully harden. There are some folks who claim you can get this to work with modified techniques, and I say their standards of succes are competely different than mine or they need to show me their data and results, because I have been experimenting with this myth for several years now and have drawers full of samples that are not above 48HRC. You can get 1084 to harden in salts by bumping the austenitizing temp up but grain growth begins quickly at the same time so it is kind of a wash. Lowering the austenitizing temp and holding a longer soak always results in lower hardness, despite what I have heard from others (I have went beyond 30 minutes in some of my tests).

5160 however will quench quite nicely in low temp salts.
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Why is that? What is the mechanism?

...remembering the O1 (containing grain refiners absent in 1084) that soaked for hours and worked well....
 
I assume you're not dessolving the carbides fully to saturate the matrix.
Somebody misses me ? That's swell. I gave Nathan a challenge but he wasn't happy so I have to be careful !!!
One factor amongst artists I've seen many times ,even within myself. The initial efforts are great artistic creativity. But then they don't know when to stop. When they pass that point it becomes a terrible micromanaging and damages the work because the spontaniousness is gone.
 
[Begin hijack] Oh, I was happy. The cut (in the project he's talking about) had a little chatter and gouging I wish wasn't there, but it was a challenging piece due to fixturing constraints and the material being cut. In all I was happy; I'm not an artist like Kevin or Tai. [End hijack]


lcf said:
I also miss Mete.
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mete said:
Somebody misses me ? That's swell.
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Yeah, I know. I read that that and was like "did something happen to mete!?"

My question was, why does a long austenitizing soak with 1084 reduce subsequent hardness. Seems counter intuitive to me.
 
Go back to the iron carbon diagram .1095 is in the hypereutectic area. You start out with spheroidized annealed .You have to dissolve most of the carbides to saturate the matrix to get maximum hardness .To dissolve all of the carbides you would have to go way up in temperature. The higher the temperature the the more carbides dissolved and the harder the matrix. You can't just substitute time for temperature .Temperature is far more influential. Remember that temperature is a linear function while time is logarithmic...
The knife is in all aspects as close to perfection as I can imagine.But you now understand that all carbides are not created equal. vanadium carbide is a whole lot more equal !
 
:foot:

duh, I get it.

I read what Kevin said "You can get 1084 to harden in salts by bumping the austenitizing temp up but grain growth..." and misread "Lowering the austenitizing temp and holding a longer soak always results in lower hardness" as meaning lowering austenitizing temperatures back to normal temps and holding a longer soak always results in lower hardness.

Obviously, if you're soaking it at below normal temps it won't harden properly. I thought his comment was about increasing the time to 30 min. I guess I need to work on my reading comprehension skills...
 
This very often ends up in total confusion when people are thinking along two entirely separate lines of thought in quenching, i.e. normal quenching versus martempering. When quenching into a liquid that is heated to no more than 150F. you can soak 1084 for 5 minutes at 1500F or you can soak for 20 minutes and either way you will get maximum hardness with little problem (as long as the quenchant is designed foe 10XX steels). What I was talking about was attempting to quench a shallow hardening steel into a liquid heated to 400F or better, which will have its cooling rate severely compromised. There are times I come close to banging my head against the wall (I don’t hair pull, I have precious little left) when bladesmiths seem unable to work out that heating a quenchant to 400F will not allow it the same cooling ability that it had at 100F.

Interrupted or timed quenching is the best way for the poor man to attempt martempering with shallow hardening steels, getting creative with alternatives at 400F is not. Industry has for years used the method of increasing soak temp to fully harden shallow hardening parts but it is a very delicate balance between grain growth and hardness. You see when you increase soak temps you dissolve more material into solution. Pearlite will form similarly to how ice forms on the surface of a placid pond; it will begin around any sticks, twigs, rocks or plants that break the surface for the reaction to begin at. So the less “stuff” you leave in the steel for the reaction to begin at, the slower will be the pearlite formation; dissolving more or even growing grains will push the pearlite nose to the right and make it easier to beat in the quench. A recent test of mine showed that ¼” 1084 could the through hardened to 65HRC in 420F salts, if austenitized at 1550F, but the grains where not as fine as I would prefer, my next step will be to explore the 1525F range. As you can see I tend to want to be certain before I proclaim something works.

If however I just want to use room temp #50 oil, I heat it to 1500F for as long as I like and quench to full hardness.
 
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I just want to say that I think Kevin has done of great job answering all these questions. Not that I agree 100% with all the answers or need to, but I feel that I should give some credit where credit is due.

I started this thread as sort of a joke, but Kevin’s taking the questioning seriously and I respect that. It shows that he’s a stand up kind of guy, and not intimidated by the line of questioning. I doubt anyone else here could do any better than he has.

We're listening.... Keep it coming bro! :)
 
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Thanks for the info Kevin, sorry that I was not specific. I was talking about salt to be used in a salt pot not for making brine or for quenching the blade in.
 
Don Hanson III said:
Kevin, why be concerned with martempering 1084 if the above works so well?

I've not ever found a need to martemper, but I'm just curious :)
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You do many swords Don? When blades get that long martempering becomes VERY attractive. Currently I still work with 1084 and 1095 and quench them all in fast oil, but it would be very nice to work out a way to eliminate one of my quenching stations and simplify my operation down to doing everything in the salts.

People need to assess their own situation and decide what works for them, and certainly not ever say "Joe Bladesmith uses XX to heat his blades and XX to quench them, so I guess I gotta get me some of that":thumbdn: As wrong as that is, it seems to be the way a large percentage of smiths set up their shop. Here is a good example, I work mostly with salts and martempering* and often describe heat treating in terms of that, thus some who think I know what I am talking about;) may decide they have to quench into 400F liquid without ever asking why they may want to do that. They may work exclusively with 10XX or W2, I work with L6 and O1 in salts, O1 and L6 like salts, 10XX and W2 don't like 400F quenchants. Now by feeling you are safe by just copying Kevin you either are set up with a proper salt bath system that won't work with your steel or you are risking life and limb with heating who knows what to 400F and sticking 1500F steel into it and fooling yourself that it is getting hard. Instead, due to that smiths unique needs and circumstances I would have advised using a fast oil like everybody else. This is why my endless mantra is for bladesmiths to stop just following what one guy says or does and start doing their own research and independant verification.

*My reasons for using this technique are many, including the ability to straighten any distortion as it occurrs, gains in impact toughness, automatic snap tempering built into the process allowing me more freedom in my work. The tempering medium being the same as the quench medium so it is right there and waiting for me to go right back in for the temper. Very clean parts right out of the heat treat. Almost instantaneous heat transfer and conduction. A wonderful protective coating if I cannot get to the blades real soon. Absolute control over temperature for my testing and research. A very clean medium that becomes a nice stable solid block in the corner when not in use. No smoke, or nasty vapors and fumes from my quenchant, in fact no vapor jacket at all. The ability to do alternaitve and advanced heat treating like austempering, although it is unlikely you would see me doing that on a regualr basis anytime soon :rolleyes:, but it is nice to have choices. Occasionally I am faced with a non-blade shape or construction which will make distortion unavoidable unless I use one of these techniques. The list does go on and on, but I could also provide a list of cons about it as well but for me personally that list is far outweighed by this one.
 
Tai Goo said:
I just want to say that I think Kevin has done of great job answering all these questions. Not that I agree 100% with all the answers or need to, but I feel that I should give some credit where credit is due.

I started this thread as sort of a joke, but Kevin’s taking the questioning seriously and I respect that. It shows that he’s a stand up kind of guy, and not intimidated by the line of questioning. I doubt anyone else here could do any better than he has.

We're listening.... Keep it coming bro! :)
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It is what I enjoy, and the reason I come to these forums- to spur independant thought and get as much information out there as I possibly can, it is still up to the individual to verify that information regardless of who it comes from. As I have previous said- I like to hand out information like free guns to an oppressed population. Few things can be sweeter than the panicked look on the face of the aristocracy anytime in history when this has been done:D

To be honest I think this has been a breath of fresh air to rattle things about and clear some dust and cobwebs, things have been boring around here lately and we have some new faces that could benefit from some intense question and answer. I think it would be great if the questions in this thread where broken down into seperate threads with titles that invited all to participate and I could contribute to my hearts content. Believe me I don't need my name attached to it to know if a person wants my input, folks have learned the topics that will press my buttons and get my attention. The problem is stopping my big yap once it gets started.
 
Kevin, I do not make swords but I can now see where martempering might be good for the really long blades.

I do what works best for me and rarely follow anyone elses lead.

Thanks for your answer.
 
My reasons for using this technique are many, including the ability to straighten any distortion as it occurrs, gains in impact toughness, automatic snap tempering built into the process allowing me more freedom in my work. The tempering medium being the same as the quench medium so it is right there and waiting for me to go right back in for the temper. Very clean parts right out of the heat treat. Almost instantaneous heat transfer and conduction. A wonderful protective coating if I cannot get to the blades real soon. Absolute control over temperature for my testing and research. A very clean medium that becomes a nice stable solid block in the corner when not in use. No smoke, or nasty vapors and fumes from my quenchant, in fact no vapor jacket at all. The ability to do alternaitve and advanced heat treating like austempering, although it is unlikely you would see me doing that on a regualr basis anytime soon , but it is nice to have choices. Occasionally I am faced with a non-blade shape or construction which will make distortion unavoidable unless I use one of these techniques. The list does go on and on, but I could also provide a list of cons about it as well but for me personally that list is far outweighed by this one.
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OK Kevin, I've seen more than a couple of smiths and even a couple of guys in the larger steel treating world that have little else to do with knifemaking list many of the same benefits for salts. Looking at what I know actually happens during HT from my own experience and reading, most of these benefits make logical sense as well as being verified by multiple sources.

To put it bluntly, I'm fairly sold on the benefit of salts for the right steel. Now, on a practical level, how does one overcome the fear of being melted alive by the volcano waiting to happen. I can be careful and methodical every time, and logically, I understand the necessary and prudent safety precautions, I just can't seem to get over that hump.

Building my own forges and forge welding with borax flux and nothing but a hammer and anvil weren't a big deal, but for some reason, salts scare the bejeesus outta me.
 
SShepherd said:
Kevin...I need to know.......






What color smoking jacket should I wear, while wearing a fez?

Solid color....oriental design...?:D
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Sorry I missed this crucial issue with all the trivial stuff discussed. The proper fez color being red, a red smoking jacket with black trim is quite stylish, however one could reverse this and have a predominantly darker jacket with red accents, although an all black smoking jacket is not acceptable. The oriental prints are always in fashion for smoking attire and almost unnavoidable in silk, which functionally is the top choice in material, however tweeds and velvets are too traditional to ignore depending upon your style. A traditional gentleman of military background would wear velvet in a Victorian style quite well and while mutton chops would almost push the ensemble into a characture at many functions, in a traditional gathering it would be smashing! Hef's indeniable fashion contribution in the later half of the 20th century sparked a revolution in the attire that cannot be ignored, thus the statement made about the wearer is quite clear in a solid color silk jacket combined with a straight nibbed pipe. I prefer the oriental silk prints in a longer length harkening back to the proper 18th century man of the world in a lavish banyan coat.

Aside from the aformentioned Hefner ensamble the pipe can be of any style the wearer prefers but the two most traditional and proper in a fully formal smoking party would be the gourd calabash or the hookah. Aromatic tobaccos should be kept to a minimum at these formal affairs unless held outdoors as the cacophony of scents can be a little too chaotic.
 
Dan Zawacki said:
..., salts scare the bejeesus outta me.
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As well they should that is how they reamin a useful tool and not your undoing. Stay focused whenever using them, follow the rules* exactly, and don't redneck engineer or half @$$ things while working with them and you will be just fine.

*never allow moisture, oils, crud, scale, rust or dirt to go into the tubes. Always insert a removable tapered rod into the high temp at the end of the day. NEVER put you face over the top of that tube for any reason- buy a hand mirror if you have to! If using a tube for low temp keep it tightly sealed and totally dry when not in use. Insure you unit heats evenly, this is not just for the heat treating results, it is about safety, molten liquid under a solid surface is exactly how volcanos work! If using electric check and maintian your tubes religiously, salt leaks are a serious matter around 220V elements and kiln sections are very expensive to replace. Clean up any spills, cloth, wood etc. that contain low temp salts, the slightest spark will produce the strong smell of fireworks in your shop and a fire that you will not extinguish, but will have to kick outside and let it burn its self out. :o
 
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