52100 steel/learning by Fire and error

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DaQo'tah Forge

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Hi my name is DaQo'tah

just did my first heat-treating on my 52-100 steel blade.

I tried to copy the way Ed Fowler heat treaded his blades in the 52100 video,,,,But it didnt go to well...

1st, this was the very first time I had ever started up my new torch,,,it was scary,, I spent most of the morning watching the Fowler 52100 video trying to study how Mr. Fowler starts his torch!

2nd, Mr. Fowler heats his oil with his torch to 160 before he starts to heat the blade steel,,,

I had Huge trouble doing this, I live in North Dakota, its so cold here, that it took forever to heat the oil that hot.

3rd, I dont understand something Mr. Fowler talks about in the video as to the right settings for my new torch,,,and the video seems to be in disagreement with the Fowler book KNIFE TALK on how to have the torch set for heating the steel....
when Mr Fowler talks about backing down the flame, whats that all about?
turn down the gas?..turn down the Ox?
yet when I watch the video he seems to still have a good size flame?...

4th,,,,as I didnt know how to set my torch, I spent about an hour trying to get the steel hot enough, this is against what Mr., Fowler clearly says in his video,,I did just what I didnt want to do.....I was bummed

5th At last got the steel to the right temp. I was about to dunk the edge into my new oil bath,,,when I noticed that the oil was now reading too cool I had taken way too long to heat the steel to temp. (remember its very cold here in the shop)..I dunked the edge anyway, but I believe that the temp of the oil was around 136-140 not the 160 I was aiming for.

However, I have used todays total disaster as a way to work out the kinks in my Fowler-type heat treating system.

I will waite 24 hours now, and see if I can improve the next days heat treating...

let ya know...
DaQ
 
I'm not a gambler, but I'd be willing to bet that even Ed has goofed up a couple. Take heart and better luck next time.
 
DaQ,
I use a torch to heat my blades and the size of the blade determines the size of the torch tip. I use acetylene welding tips and have several sizes because of the different requirements of heat. On the oil, you can set it on a small heater or do as I do and use an electric skillet. The skillit isn't very deep and is good for the small knives. I put a standing pipe in the skillit with the oil in it for the longer knives and quench point first.
The flame setting I use is a neutal flame which means that after the aceteylene is lit, the oxygen is turned on until the secondary flame dissappears. Did you check the blade for hardness after the quench? If the blade was cooled quickly enough, it will still harden. The reason I heat the oil is to thin the viscousity of the fluid so that it will cool faster. The thinner oil will remove more heat in the blade faster. I heat my oil to 300 degrees and have no problems at all. The only problem I know you could have had is to heat the blade too hot and cause some grain growth. It doesn't sound like a disaster to me.
I will have to watch the video again to see what he is talking about when he says "backing down the flame". It has been too long since I watched it.
 
Hi this is DaQo?tah

Today went a lot better for my 52100 steel. I fixed the problem I had of taking too long to heat up my quenching oil by building a electric heater for the oil. I found an old portable one electric burner, and set my whole oil bath on top of it. Yes it took a while to get everything to set right and stay steady. But with my wifes help and a bit of wire, I ended up with a darn good oil heater set-up.

With just a flick of the burner knob I was heating my oil, once it was up to the right heat (160) I just had to turn the knob down to 4 to keep my oil at the right temp.

That problem solved, I was able to concentrate on just heating the steel with the little gas I got left in my torch.

The 52100 steel heated at the same rate as in the Fowler video today, so I must be doing something right.

Tomorrow I do the last of the 3 heatings on my 52100 blade, then it will be time to temper it in my wifes oven,


Raker - well, now about the "check the edge to see if its hard" idea...

I saw Mr Fowler talk about doing that in the video at this time, but he dont really tell me what that means to do. Way later in the video he slides the finished edge across a file, but as my edge is still as thick as a quarter, Im not sure what I would learn?

what do you do?
 
To check the edge, the file will not cut it and will slide. It may hang just a little on the start because of the sharp corners on the edge, but the next time you push the file across, it should slide without cutting. The thickness of the edge has nothing to do with how hard it is and a quarter thick is alright. On smaller knives, I may go down to a dime thickness on the edge but never thinner.
If you get an electric skillit, once you get the temperature set, you can just unplug it and then later on plug it in again and it will be right where you left it on the temperature.
 
This isn't rocket science! Just keep using what you have available but keep a record of what you did. You may want to repeat what went well, or like me, you may want to avoid past mistakes.
Destroy a few. Not your first one, of course. I learn more from my mistakes than when everything goes well.
Still trying, Lynn
 
What you do with the flame of the torch is to do like Ray said and bring up a good neutral flame. After you get a good neutral flame then start shutting the oxegen back off. As you do this you will see a feather start to grow on the inner cone of the tourch flame. When this feather reaches a length of about three times that of the inner cone your touch is where it should be.
 
Bill, I use a slight feather, just enought to be sure that it isn't an oxidizing flame. When the feather is three times as long as the cone, that is considered a carburizing flame. This will add carbon to the surface of the steel when the steel gets hot. I have seen plain mild steel (A-36) get hard enought to break by adding carbon to the surface of a 1/8" piece :). If you are heating without the feather touching the steel, it will not add carbon. When using acetylene/oxygen, the cone's temperature is 6000 deg and the area in the outer flame is 3000 deg., at least that is what the Victor cutting guide lists.
 
this is DaQo'tah

man I love this website!,,,INFORMATION, I love to just ask and get the information I lacked all day today.

so,,if I got this right, I start with equal gas and Ox...Then I turn DOWN the Ox untill there is that feather thingy growing out of the inner cone....correct?

AND...
Now let me see, Raker, you said -"If you are heating without the feather touching the steel, it will not add carbon."...

so this means that I make darn sure that the feather hits along the blade edge, correct?

Well, in the afternoon tomorow I will do the last heat treating (If I got enough gas left that is),,,ahh, but then on tuesday I need to temper in the oven (400 for 2 hours,,3 different times)

QUESTIONS;-
In the Fowler video, Mr. Fowler does not talk about sanding between heat treatments,,,but when the heat treatments are over and he then tells me how to temper the blade in the oven, the blade he has in the oven is nice and clean and looking sharpened,,Do I as well sand to a sharp edge before I temper?...or after the knife has come out of the last oven tempering?

also,after the oven tempering I then will etch the blade, do I sand and buff it after the etching?..I worry that the sanding and buffing will hurt the look of the etching?

I know that I keep asking what must be foolish easy questions for you guys,,,But this is my first real knife, all the ones I made before were toys ment only to hang on the wall,,,,After I do this first Knife, I know it will get easyer for me..

thanks DaQ
 
This is how I do mine, I don't clame to be in the same class as Ed, but here goes.

after forging and grinding, noralizing and anealing cycles, I take to at least a smooth 320 grit finish, no sharp corners, and a an edge between a dime and a qaurter in thickness.

I have a oxy/propane torch wich I set at a very slightly carbonizing flame and slowly work the torch flame over both sides of the edge, spending just a little longer on the ricasso to bring the temper line into it. I don't let the inner cone touch the metal, one I don't want to add carbon or change the alloy, two the inner cone will get your metal too hot to quick. Once I have the lower third to half just a hair above non-magnetic I quench point first in the oil, rocking back to get the edge hard. When heating the edge I am right next to my quench tank so all I have to do move the torch out of the way and quench, I can go from heating to quench in under a second with the tank right next to me. After the back is cooled to a black heat I lay the whole blade in the oil and let the whole thing cool down.

I then wipe off any oil with some saw dust and check with a file. A file should bite into the soft back and spine, scate on the hardened edge. After the third quench the edge will still scate a file, but will feel 'slightly' softer due to the grain refianment.

Between quenches I let sit 24 hours in my home freezer, up north in the winter thats not realy necisary, but down here it lets me get consistant results.

When I temper I run one side of the blade on the grinder to give me clean steel to check the oxide colors as a fail safe. I start tempering 52100 at 375 deg.F., 3 cycles, 2 hours each, takeing out of oven to cool between cycles. On the last cycle I leave in the oven and let the whole thing cool down. BTW, don't trust oven settings, get an oven theremomiter to give acurate temps, and let cycle for about 20 minits to even out befor putting your blade in. After tempering I do the final gring and test the edge on a brass rod. If the edge chips I retemper 25deg.F. hotter for 2 hours till the edge quits chipping out. So far I've never had to go over 400 deg.F. on 52100.

I finish to a 600 grit finish and etch in a mix of 1 part feric cloride and 4 parts water for about 10 minits, do a lite buff with white rough. If you buff to long you can remove the temper line, or you can polish and still see it in the light for a sutle efect, or you can go bold and after etch just wash clean and rub with Flitz metal polish for a bold finish. Experiment and see what you like.

Good luck, hope this helps and lets see some pics:)
 
DaQo'tah,
I don't do some things like most do on heat treating. I don't use the carburizing flame to heat my blades. Using 52100, there would be no need to add carbon to the surface of the blade.
Since this is your first blade, 400 degrees will be alright for the first time you do your tempering cycles (2). Since you haven't used the steel before, I would suggest that you use the brass rod to check the blade before you put handles on it. Since everyone will do things a little different, the results will be slightly different. My red will not always be your red if you know what I mean.
As far as sanding, you can knock the scale off with a sander or whatever and then put it in the oven so that you can also see what color the metal will be at the temperature you are using. That would be another check on the repeatability of the heat treat. If for some reason the oven was turned while you were using it, you would be able to know by the color.
Good luck on the blade and I hope you will make many more. It is a very enjoyable lifestyle.
 
Raker,

You are right. This is a carburizing flame, but it is there to help keep from burning out carbon not to add carbon. The migration of carbon in, or out of a blade Is somewhere around .018 per hour at 1850 degrees F. The blade should never be close to that temp., during heat treating, so it is possible that the carburizing flame does nothing for the steel, but it shure dosn't hurt anything either. :D And this is the way that Ed hardens his blades.

DaQo'tah,

You can sand the surface of the blade so that you can see the tempering colors if you want but it isn't neccessary. Just make sure that you are certain of the temperature by using an oven thermometer. after tempering then grind, sand and finish the blade. If you are using a convex grind take it all the way down to sharp. do the brass rod test. then sharpen on a stone and see if you can cut rope. If you are going to finish the blade etch it just before you put on the guard and handle.

Bill
 
My very first ever Tempering in an oven will be on, Tuesday, but is it a one a day thing?..can it be a 3 day thing?...

the reason I ask is, 2 hours at 400, then let cool (1 hour?), then another 2 hours/cool/another 2 hours,,,well,,thats a whole day!

could I do 2 hours at 400 on one day, waite 24 hours, come home from work and do the 2nd 2 hours at 400? and the 3rd tempering on the 3rd day?
 
I am very pleaed when I read your questions and the answers that have been provided. I am proud of all of you. thanks for doing your best to make the kind of knives folks can count on. The day is long past when the average consumer of our products will have the need or ability to know how good his knife is. It is up to us to know and provide great knives for those who seek them. DaQuoTa, you are an inspiration, seeking and doing it the hard way, that is the way most of us started, I started a long way behind where you are today. Thank You.

I have been practicing the flame hardening mentod you describe for over 25 years. (I don't count the poor efforts before that) At one time I practiced hardening a blade made of mild steel, just to get the hang of it. I probably hardened that blade 50 times. Naturally it did not get hard, but it provided a lot of learning. I continue to learn with each blade I harden and then etch. There are many variables we can play with, this is one of the joys of making knives.

Stick With It my friends and take care
 
this is DaQo'tah

Let it be know that I have completed the first tempering session for my 52100 blade. Im pleased to report that there were no anomalies, nor were any cats injured during this procedure.

Y
 
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