What is left on the table after a poor heat treat?

[oic0]

By poor I mean eyeballed and with non quench specific oil.

I am still playing with 1084 and after each heat treat I test it against my old mans stainless pocket knife, if it catches anywhere that should be hard, I start over. I've been able to get them what seems to be well hardened to me. The last one I made I only tempered to 365 for an acute chisel grind kitchen knife and it got hard enough it was eating up my cheaper stones trying to sharpen it. If I am able to get them hard enough, am I still leaving something on the table with a torch and canola oil heat treat?
I do not have enough spare cash to buy a kiln and I'm just a hobbyist. I am debating whether or not to send off my better creations to professional services, especially if I plan to spring for a decent handle material. If they could perform significantly better It would be worth it to me.

 

[Patrickknives]

I am just going to jump in and say yes, this assumes that a professional with state of the art equipment can do better than your torch and canola oil. I suggest you keep one of your blades and send one out and do some comparison. The cost is not alot but the main issue that most have is the time to ship and get the blade back. I had your same quandry and now send out everything for HT, (and I have a kiln).

 

[Robert Dark]

I am just going to jump in and say yes, this assumes that a professional with state of the art equipment can do better than your torch and canola oil. I suggest you keep one of your blades and send one out and do some comparison.

I agree with Patrickknives. If you have a means to do basic heat treat, then you can compare your results with theirs.

I would recommend that you begin the long study of heat treat and the various methods/equipment associated with it. You will quickly find that it is a never ending journey.

Good luck, and keep us up to date.

Robert

 

[David Stifle]

Heat treating is fun, and awful too. I've been at it for quite a while, and I've gotten really good with certain steels. Others, not so much. My advice, read, ask questions, upgrade your equipement when you can, and as Robert said, enjoy the never ending journey. And yes, when you come up with a extra nice blade, then by all means send it out. But, do practice, over and over.

 

[Joe Calton]

you can get great results using a torch and eyeballing it, with canola. provided that the torch is an oxy/act torch, and that you eyeball it with the help of a magnet.

ive never used a kiln, just my forge for heating for the quench, I have used a torch and it is a good method if you practice. the burner on my forge comes in from the side, pretty close to the front, and that allows me to "paint" the heat onto the blade just the same as you would with a torch, except that the blade is surrounded by a nice warm chamber instead of being exposed to the air at room temperature. this set up works really well for me. it also helps to maintain consistant lighting in the shop everytime you heat for the quench. in my case, I have the garage door closed, I have no windows, and of all the different lights I have, only one is on, the same one everytime I heat treat.

when I work with 1095, {i havent ever used 1084 but it should be close} I use canola oil, preheated to 120-130 degrees and do mostly edge quenches. you can tell alot about your heat treat by the scale pattern after the quench, and then again after finishing the blade out by etching it in ferric, and of course by doing performance testing, the brass rod test, rope cutting, ect...

If you are on a tight budjet, Id suggest staying with the torch since you already have it and practice practice practice. or you could make a heat chamber to put the torch up to to hold it steady, while you move the blade back and forth while keeping some of the heat around the blade so it doesnt cool off so fast in the room temp air.

 

[T Toth]

Okay Joe what about the magnet? I'm still trying to learn more about the magnet in use? I myself seem to be happy enough heating with torch for hardening. I aim for blue bright blue and lots of crimson / okay purple is what I chase down my blades. i also take it all with grain of salt, meaning the shades vary but as long as it does not go into annealing stage it's cool. They are right it is the eyes that tells ya and the fun of doing it. BUT what about all this magnet talk I'm still waiting Joe

 

[Barry Clodfelter]

Tie a magnet to a string and hang it near where you are doing your heat treating. When you think the blade is ready move it back and forth in front of the magnet. If the magnet moves you're not quite hot enough and if the magnet doesn't move you might be there. I say might because most carbon steels goes non-magnetic around 1425 and you are shooting for around 1475. You need to discover and learn what the color of the steel is as soon as it gets non-magnetic. The darker you can get your work area the better. Also you'll want to have the same conditions everytime you heat treat. The color of the steel won't look the same in different ambient lighting.

 

[Joe Calton]

t toth, the magnet is used for judging the hardening temperature, i just use an old speaker magnet to tell when the portion of the blade that I want to harden becomes non-magnetic, then the temp is allowed to climb just a bit and then into the quenchant.

I have seen folks tying the magnet to a string, but I just hold it in my fingers and draw it along the side of the blade. the magnet I use isnt a real strong one. its about 1.5" in diameter so my fingers stay far enough away from the steel so I dont get burned.

the crimson/purple colors are tempering colors, and happen after the blade is hard. I dont use a torch for tempering, I just use a toaster oven with a couple oven thermometers in it, and set the toaster temp with the thermometers to the temperature that gives me the best performance in the brass rod and cutting tests. I dont use color to judge the tmepering temperature.

 

[daizee]

I am using methods very similar to Joe for 1084 and 1095, though we use a propane torch in the two-brick forge. Propane in free air isn't quite enough. The magnet is usually a small level with magnets in the base - this gives you a lot to hold onto an leverage to pry it off the hot blade if you have't reached temp yet.
Results have been satisfactory.

My understanding from lots of reading around here and elsewhere, is that with 1084 you can realize all of its potential with a simple torch/forge setup and a warm canola quench. That's one of its several great appeals.

-Daizee

 

[oic0]

I wanted an oxy acetylene torch but couldn't justify the tank rental price. Bought a propane torch at harbor freight. It could never cut steel like a real torch, it puts out a large flame like a jet afterburner. Sort of like a propane forge nozzle and venturi on the end of a stick. Once you learn to hold it just right, it will heat fairly evenly so long as the blade isn't to thick or clayed. I haven't had any trouble getting them hot after I started holding them lengthwise several inches from the torch. When held perpendicular the middle of the knife would never get hot enough. If I don't manage to blow the scale off the full length of the edge from the steel expanding when it transforms, I heat it up and try again.

I know I can't do a good job on any complex alloys or steels with more carbon than 1084, I was just wondering if there is still more to be had from 1084 with precise temperature control and specialized quench oils.

 

[me2]

You could probably wring a little more out of 1084 with just the right stuff, but you'd have to test your knife carefully to see it. Here's something that will really blow your mind, just cause I feel like causing trouble. 1084 will harden without reaching non-magnetic. Enjoy chewing on that, but don't get rid of your magnet.

 

[Joe Calton]

I just noticed that you are in shreveport, isnt Darrin Sanders there? I think he does heat treating for others, you might be able to just drop one by his place and then wouldnt have to send it out of town.

someone else just had a hammer-in there so you should be surrounded by knifemakers. do a search for shreveport hammer-in from the last couple months and you should find someone really close to you.

 

[daizee]

Iclayed. I haven't had any trouble getting them hot after I started holding them lengthwise several inches from the torch. When held perpendicular the middle of the knife would never get hot enough. If I don't manage to blow the scale off the full length of the edge from the steel expanding when it transforms, I heat it up and try again.

I would be concerned about burning a lot of carbon out of the surface of your blades with that much direct heat. That would mean more soft steel to stand through after tempering. Hopefully someone with more technical knowledge will chime in and confirm or correct me though.

 

[Rick Marchand]

I would forgo using a torch, completely. You have no control of heat. It is a constant battle between the cool body of the blade and the ever-fluctuating heat at the edge. Can you harden with a torch? Yes. Can you make a functional knife with a torch? Sure. Are there better ways to do it? Definitely. I urge you to do some research into the mechanical properties of the various structures in steel. Find out what you want your knife to be made of and use the method that best gives you that structure. If you feel you need a differential hardness, temper back the spine. Tempered martensite is much stronger than pearlite and whatever else you are ending up with in the transition zone. If you are looking for the asthetics of a hamon, use clay or edge quench.

 

[oic0]

I just noticed that you are in shreveport, isnt Darrin Sanders there? I think he does heat treating for others, you might be able to just drop one by his place and then wouldnt have to send it out of town.

I think Darrin is a few towns over. I actually went to the hammer in and I've met some of the local makers, but none of them that I know of heat treat as a service. I have had a few tossed into batches of other makers knives when they were doing their own heat treating, but I wouldn't want to bug those guys every time I make something.
I'm not too bothered by the time it takes to pay and send stuff off and get it back, its just that with me being a hobbyist and in the learning phase, thats $20 to $30 I could have spent on abrasives and steel. Every now and then I make something I like enough that I might want the best for it, its just a matter of knowing what I am missing out on so I can draw that line if you know what I mean

I would forgo using a torch, completely. You have no control of heat. It is a constant battle between the cool body of the blade and the ever-fluctuating heat at the edge. Can you harden with a torch? Yes. Can you make a functional knife with a torch? Sure. Are there are better ways to do it? Definitely. I urge you to do some research into the mechanical properties of the various structures in steel. Find out what you want your knife to be made of and use the method that best gives you that structure. If you feel you need a differential hardness, temper back the spine. Tempered martensite is much stronger than pearlite and whatever else you are ending up with in the transition zone. If you are looking for the asthetics of a hamon, use clay or edge quench.

I didn't even think about that. I've been heating the full blade and quenching only the edge, I guess I'm making some awful soft spines on knives that could use something more in the range of spring steel in the spine :foot:

 

[Rick Marchand]

I didn't even think about that. I've been heating the full blade and quenching only the edge, I guess I'm making some awful soft spines on knives that could use something more in the range of spring steel in the spine :foot:

If you need or want a soft bendy spine, edge quench is the way to go. I just can't see where the need for a knife to deform and bend is a plus, outside of the ABS performance tests. I would rather have it strong enough to take whatever you throw at it.

I'm just giving you options and suggesting that you make a knife from the inside, out.