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colu41

colu41

Joined
Dec 24, 2014
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So I got my forge setup and my quench ready. Heated up an old mild steel blade I practiced on until glow red, and popped it into the gallon of canola oil. I then started on my first actually knife blade!
Anyways, got it heated evenly, and at a mild red glow. I took it out of the forge, and magnet tested, and it was not magnetic. As a just in case I popped it back in the forge for a good 30 seconds, then I finally quenched. So far so good!
When quenching it smoked a little bit and smelled like I was frying a turkey, but it didn't flame up which I'm happy about. I let it quench for a good couple minutes while I was heating my 2nd blade. And the same. I then cleaned them off, dried them, and brought them down to my oven and sanding "station". I did the file test on it. And it still seemed to leave slight scratching on the blades?
I heard it is suppose to slide over it like glass and not cut in at all. It did feel like it slid across it more than before treating, but it still left silver scratches on top of the now blackened blade.
Is this normal? Am I doing something wrong? They are tempering as we speak at 400*. I going to do the first temper at 1 hr 15min. Let them cool, and then do another at 400* at 1 hour.

I feel I'm doing everything as directed for this 1084 steel.
Any help would be so greatly appreciated. Because this step of the knife making process was the one that really got me worried before I got into this.
 
Probably decarb. You're gonna have to grind that blade down a bit to reveal the hardened steel. The steel that's been exposed to air during h.t. loses a good portion of its carbon and won't harden up.
 
That would be a huge relief. Everything went way to smooth for there to be a problem but, I guess its my first time. I should expect some hicups. Hope to post my first finished knife very soon!
 
Im treating my first actually knives of 1084. The mild steel I used just to heat up the oil.
 
Sounds like you are doing a good job and you seem excited. That's good. In your excitement don't rush or skip steps in an effort to get the thing finished. You will learn more and come out with a much better product than you realize if you slow down now and really concentrate on doing the best you can. Don't forget to post some pictures!
 
i4Marc said:
Sounds like you are doing a good job and you seem excited. That's good. In your excitement don't rush or skip steps in an effort to get the thing finished. You will learn more and come out with a much better product than you realize if you slow down now and really concentrate on doing the best you can. Don't forget to post some pictures!
Click to expand...

For sure. This is the one hobby (out of many) I've done where I am absolutely going by the book. And I'm literally doing research on every little thing before I go do it. I think I am definitely ready to get better, and make some nice stuff!
I will definitely post pics soon.
 
I heat my canola up by putting my quench bucket in a large pot containing boiled water and measure it with a thermometer. Might be a more consistent method than heating up a piece of steel.

I agree with leifjl, let's see some pics!
 
zhyla said:
I heat my canola up by putting my quench bucket in a large pot containing boiled water and measure it with a thermometer. Might be a more consistent method than heating up a piece of steel.

I agree with leifjl, let's see some pics!
Click to expand...

I should do something like this....I will upgrade my setup eventually. But how important is the oil temp when quenching?
 
Most oil quenches steel best at around 120-140F range. At that temp it has the best conductivity and convection. ( parks #50 is used at room temp - approx. 70-80F)

Heating the oil is usually as simple as heating up a bar or rod of steel/iron red hot and stirring the quench tank full of oil with it. Check the oil with a frying thermometer or a cheap laser thermometer from HF ( about the only good use for them).

The temperature of the blade should be as close to the proper austenitization tempo as possible, but don't worry too much about the oil. Any temp in the 110-150 range would be fine. 130F is just the center target.

Make sure the blade is fully austenitized. That would be reaching non-magnetic and then about 50-100°F higher. Most new makers think it is hot enough too soon. Quickly checking with a magnet often will let you know just when it becomes non-magnetic. At that time it is slightly above 1400°F. Once it becomes non-magnetic, watch the color as it rises about one shade red brighter.........and quench. Except for when it is ready for quenching, don't take the blade out of the forge after it becomes non-magnetic unless there is a problem.

Also, it is the edge you are trying to get hard. When checking with the magnet, check along the edge area ( just about 1/4" above it is the best place). The spine may be lower in temp. In a HT oven the whole blade is heated evenly, but when using a forge or other flame source, pay the most attention to the edge. Try to heat the spine evenly by placing the edge downward or against the side of the forge. Rotate it constantly and see how even you can get the color....but pay attention mostly to the edge. If the edge gets too hot it may cause problems.
 
Stacy E. Apelt - Bladesmith said:
Most oil quenches steel best at around 120-140F range. At that temp it has the best conductivity and convection. ( parks #50 is used at room temp - approx. 70-80F)

Heating the oil is usually as simple as heating up a bar or rod of steel/iron red hot and stirring the quench tank full of oil with it. Check the oil with a frying thermometer or a cheap laser thermometer from HF ( about the only good use for them).

The temperature of the blade should be as close to the proper austenitization tempo as possible, but don't worry too much about the oil. Any temp in the 110-150 range would be fine. 130F is just the center target.

Make sure the blade is fully austenitized. That would be reaching non-magnetic and then about 50-100°F higher. Most new makers think it is hot enough too soon. Quickly checking with a magnet often will let you know just when it becomes non-magnetic. At that time it is slightly above 1400°F. Once it becomes non-magnetic, watch the color as it rises about one shade red brighter.........and quench. Except for when it is ready for quenching, don't take the blade out of the forge after it becomes non-magnetic unless there is a problem.

Also, it is the edge you are trying to get hard. When checking with the magnet, check along the edge area ( just about 1/4" above it is the best place). The spine may be lower in temp. In a HT oven the whole blade is heated evenly, but when using a forge or other flame source, pay the most attention to the edge. Try to heat the spine evenly by placing the edge downward or against the side of the forge. Rotate it constantly and see how even you can get the color....but pay attention mostly to the edge. If the edge gets too hot it may cause problems.
Click to expand...

Thanks a ton! But Im not quite understanding what you meant by:
"Except for when it is ready for quenching, don't take the blade out of the forge after it becomes non-magnetic unless there is a problem."
I sort of have to take the blade out to check it with a magnet....should I not do that? I'd have to reconfigure the forge as I made it sort of a one blade forge. Not much room to stick a magnet in there but, I can play around with it.

Right now I'm heating it to glowing red, take it out for maybe 2 seconds, checking it with a magnet, if it is non magnetic, it went back into the forge for maybe 30 more seconds. Should I go longer?

Also, would I be able to "re-heat treat" these 2 blades I did? I'm still not sure if they are truly hardened I really should get them checked somewhere but I think maybe I just didn't heat them long enough. So I'd like to do it again, but not sure if that screws with the blade.
 
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I think he means after your get to the non-magnetic point and have checked it and have found it to be non-magnetic then put it back in for that last 50-100 degree rise and watch it but dont keep pulling it out until your ready to quench.

Jay
 
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