Quenching medium for 1095

[jdale]

Through some clever trickery I was able to justify to myself enough reasons to purchase the parks #50, it should be here on Thursday.
Thanks for the offer Kevin, I might have to take you up on it some time. Maybe it would help correct some of the incorrect information I was given during my knife making class. To think he had actually convinced me tranny oil would yeild great results as a quenchant for 1095.

[Kevin R. Cashen]

Oh I am sure your instructor gave you the best he had. There is some disagreement among makers on how to do things but most of it is simply a result of differing goals, how to meet them and the interpretation of the results. One of the most classic examples of this are the very large numbers of makers that find steel that skates a file a total hardening success, while those who follow Rockwell numbers have a different outcome and expectation. Both are a measure of hardness but they are two different types of hardness and so long as you know your goals and who to measure them things just sort of work out for you.

On the transmission fluid, as I said there are automotive products that have some pretty good thermal handling qualities but they were not made with people breathing their vapors in mind, and so I feel the most responsible thing for me to do is not go too much into them without being sure of what the long term health effects could be.

[Doug Lester]

Also I think that if you go to the grocery and price peanut or canola oil in gallon jugs and compare the price of 5 gallons of it to 5 gallons of Parks #50 you might see that the latter is not too much more expsive.

Doug

[Kevin R. Cashen]

Heck it was not too long ago, back in the good ole days when you could buy Parks #50 by the drum straight from Parks, that it was hands down cheaper to get 5 gallons of heat treating oil than 5 gallons of any cooking oil or automotive product. The last 5 gallon bucket that I sold was at my cost for around $35. Now you have middle man markups, added shipping and the main company themselves heavily increased their prices, but if you maintain it well, it is a very long lasting investment for a knifemaker.

Also- please don't forget Houghton International in these discussions, they are the largest quench oil manufacturer and are much more friendly to deal with, well worth looking into! Most of the other relabeled quench oils out there are actually Houghton's stuff.

[Rog]

Yea WBE, infact it's all I have ever used, going on 6 yrs now. Its a little dirty, but still no smell, and like I said "very wet". Got the basic mix out of the $50 dollar knife shop book.

[WBE]

Originally Posted by Rog

Yea WBE, infact it's all I have ever used, going on 6 yrs now. Its a little dirty, but still no smell, and like I said "very wet". Got the basic mix out of the $50 dollar knife shop book.

I'm not surprised. The chapter on heat treating in that book should have been removed or revised long, long ago. You are one of many who have been misguided by the misinformation presented there. That book was writen with good intentions, and much of it is helpful to beginners, but the chapter regarding heat treating is so far out whack, it would be humorous, were it not for the many who have sadly followed it's advice.

[Doug Lester]

I think that we need to remember that Goddard's Goop was developed with a specific purpose in mind. That being to be transportable without a risk of it sloshing all over the trucn of the car transporting it. If it is used, I would recommend that it be brougnt up to about 120-130 degrees just like a regular oil quenchant.

Doug

[Rog]

Well, its hard to quit using something that works, what would you suggest and why? I've been heating it to about 120 with good results. A file glides right across my blade edges on 1095. Temper at 375 for an hour three times. So far so good. Am I missing something?

[WBE]

You only think it is working because 1095 is the great fooler among beginners. It fooled me for a while. The file test is NOT VALID with 1095. I can promise you that you have a mix of pearlite and martensite in your blades. No good. What you are getting is hard clumps of martensite, surrounded by soft pearlite. The file skips because it is only hitting the hard clumps and cannot cut to the soft. Think about the condition that makes your edge. To be acually hard, 1095 requires a cooling quench that will drop the temp from about 1475?/1500? to below 900? in about .8 of one second. No oil will do that, so we have to settle for close enough with Parks #50, which cools 1095 at maybe 1.2 or a tad more seconds. I'm thinking your mix is maybe 8/10 seconds in this process, or even slower. I am being generous in that guess. That amount of time allows the austentic steel to convert much more to pearlite than to martensite. 1095 is a steel best left to those with heat control, and the proper quench oil. Brine will do the job better than Parks #50, but is risky to your blades for cracking them. I guarantee, and promise you, that you will get better edge holding blades by switching to 1080/84 steel. It is not nearly as picky as 1095, but in any case, you need to lose the goop quench. Canola oil will even do a fair job of hardening 1095 if you insist on using that steel. It is the fastest speed of quench among the vegetable oils. It will do a fine job on 1080/84 if heated to around 130/35?. Try it. You'll thank yourself. I suspect that you have seen many known makers using 1095, but most have controlled heat with the proper quench oil. 1095 can be a great steel when heat treated correctly, but very poor when not. It is not user friendly for those without the proper means to HT it. 1080/84 is relatively easy to get good results with, and will out perform your 1095 blades to a degree that you would say "What did I think I was doing with the 1095". BUT, you have to change your quench, as well as your steel, or invest in what will make the 1095 TRULY work.

[Rog]

So, you are saying that Parks #50 is the only thing that will work properly with 1095? And as far as heating the 1095 I'm getting it to nonmagnetic then putting it back in and bringing it up Little to a brighter orange, even color throughout the entire blade. Then edge quenching. Is that right or wrong? What technique or things would it take to get it right? I should have said that I also have been using a lot of 01 tool steal. How is that affected by my technique and goop?

[WBE]

Your heating of the 1095 is probably as right as you will get using a forge. It should at worst be adequate, but you need a better quench medium. One clue you might use is that if 1095 is hardened as it should be, a 375? temper will leave you with a very brittle edge. It will chip and rag out very easily, and be very difficult to sharpen. A file should barely even scratch it with that temper heat. As far as the 01, you cannot get a good heat treat using your available equiptment. 01 requires contolled temp soaks because of the alloys in it. It requires a HT oven, or molten salts, and a medium speed quench oil. Again, a file will tell you very little of the acual condition of the 01. When heated for the quenching, the carbon will easily and quickly dissolve, but the chrome, vandium, and tungsten take much more time to form with the iron and carbon to an homogeneous solution with even despersal of all these involved. 01 is a great steel, and I use it exclusively, but it cannot be HT'ed in a simple forge. Back to the 1095, you can get acceptable results, not the best, but acceptable using canola oil heated to about 130/135?. Now, unless you are trying to get hamons on your 1095, you will get a stronger blade by fully quenching it, then soft back tempering the spine with a torch. Tempered martensite is the strongest condition of high carbon steel. Again, I would suggest you buy some 1080/84 steel, and not bother with the others you have, until you have better equiptment.

[Rog]

I have a Temco thats rated to 2000 ?, that I have never used. It came out of an old wear house someplace, a Nephew gave me and I do have a plug-in for it. So whats the soak time and temp for the 01? Would it be useful with the 1095 at all? And OK, I'm going to the grocery store for some oil. Was Goddard not a good knife maker (nut)? I guess anybody can write a book. Now Ill question everything. Iv'e read (on this site) that back tempering is way too iffy to use, by more than one person.

[Doug Lester]

The other thing to remember is that not all 1095 is created equal. The manganese levels can, and do, vary and that will influence heat treating. I think that I've noted before that the 1095 that Aldo Bruno sells at The New Jersey Steel Baron was formulated specifically for knife making with a little higher manganese. From all reports that I've heard about it, including those from smiths at the hammer-in we were attending, said that it hardens fine in oil. I immagine that the 1095 that some commercial knife makers use also is formulated specifically for knife making, besides the fact that they have the equiptment to handle it. Most 1095 out there on the market is not formulated for knife making and will be so shallow hardening that the actual cooling curve from your quenches will cut through the nose of the curve on the IT diagram and give you a mixture of martensite and pearlite as WBE said.

What does all that mean? It means that you may well be getting good hardness with this batch of 1095 that you have. Just don't expect it with the next batch. It may or may not occure. This leads me to my next question. How have you tested the performance of your blades? Nothing beats hard use.

As far a soaking 1095 at just above austinizing temperature, I would still give it about 5 minutes. Granted, it doesn't have much in the way for carbides from alloying elements but it does have cementite (iron carbide) and it could use a little time to release it's carbon into solution. Though it does disolve quicker than the other carbides.

I will have to differ with WBE about not being able to heat treat O1 in a forge. Many people do it, including at least one Master Smith. They get good performance from the steel treated this way, they just don't get the best performance form it.

As far as edge quenching goes, here's another can of worms. One thing is what you are trying to get from the steel by doing it. If you are trying to get the softest back you can for a big chopper, or to pass the ABS performance test, to maximize toughness in the spine, it's a good way to do it. Probably the easiest. However, unless you just want to display a quench line, I see no reason to do that with a smaller utility blade or something like a skinning knife. I think that some people, including me when I was a new newby, think that this is a necessary characteristic of a superior blade. It's not, but it does have it's applications.

Doug

[Rog]

OK, getting smarter. How about these M-2 planer blades I have, and using the HT oven on all of it, 1095, 01, ,M-2, and 1080/84? What technique do you use for blade testing? Thanks guy's, I'm listening.

[Rog]

And yea Doug! I thought edge quenching was a prerequisite for a good blade. I had wondered about it's usefulness on small blades too.