Can you HT 1084 with just two propane blow torches? My first knife hand tools only

[BC Bushcraft]

Hey guys, this is my first post on the forums but I have come here often to read about knives.
I am making my first knife and documenting it on youtube my channel is BC Bushcraft, but I am not here to promote the channel.
I have just finished filing the bevel of my knife, it is a scandi made from 1/8th 1084 and roughly a 6inch knife in total length.
I filed to about a nickel thickness and have to do the pre HT sanding, drilling, etc, still.

So my question, I have never HT a knife before. I was wondering if I could somehow stand two bernzomatic propane blow torches pointed on an angle towards each other to HT the knife. This way I would have two heat sources heating both sides of the blade. I have seen the whole coffee can forges/ fire brick type forges but I was wondering if I can just use two blow torches with no bricks. I understand that there will be a lot of heat loss this way, so I was wondering if it was possible.

I will be doing the whole non-magnetic test to check for the temp. Pre heating the quench oil, canola, with a railway spike.

Let me know your thoughts and suggestions.
Cheers Dave

 

[ti lock]

i don't think so.... I believe you need a kiln of some sort... https://www.youtube.com/watch?v=98lh5Q0M0cg

 

[Blue Sky]

I believe it can be done. Two torches sounds like a good idea to keep the sides heating evenly and avoiding any warp when quenching. But don't take my word for it, I suggest you ask over in the Shop Talk forum, those guys know their stuff.

http://www.bladeforums.com/forums/forumdisplay.php/741-Shop-Talk-BladeSmith-Questions-and-Answers

 

[AF]

Maybe with such a small blade...but I recommend you build a coffee can/paint can forge.

 

[mabrowns]

Use map gas it's the yellow bottle burns way hotter than propane

 

[grybsh7]

Type heat treating with torch into the Youtube search box.
Lots of videos.

 

[NJBillK]

How are you going to be holding the knife?
How are you going to be quenching the blade?


The best you can reliably hope for is a differential hardening, like they do on Beckers. A soft tang and hardened blade.

You can do this, but you will need to set up as best you can prior to your attempt.
- At least one gallon of canola oil (2+ is preferred), this will need to be heated to 120°-130°. Heat a cheap piece of bar stock from a home improvement store with your torch and dunk it in the oil, reheat and redunk, over and over until brought up to temp.
- Check your oil temp with a meat thermometer or an IR one from harbor freight.
- I would hold the blade by the very end of the tang with a set of locking pliers (like vice grips) and clamp those to a table or workbench with a quick release c-clamp.
- within arms reach, you will want a magnet held in a set of pliers, you will need this to check your knifes temp. It will need to be mobile since your knife is clamped down.
- Run the torches back and forth, continuously moving, over the spine and flats area and let conduction bring the blade area up to temp.
- Once the blade is no longer magnetic run the torches for a few more seconds to bring it one shade brighter (this will offset the travel time of no heat to the oil).
- dunk your blade in the oil, tip first. Move the blade vertically and edge to spine to shed the heat as quick as possible (If you go side to side you risk warpage).
- Check with a file for hardness, it should skate and not bite too deeply (more on this at the end).

Hardening is done, tempering next.

- Once your knife cooled to being able to touch, you can check for warpage. If there is any, you will have to wait til the second or third temper to straighten.
- Preheat a toaster oven to 410°-420° and let it stabilize, use the meat thermometer to watch the temp.
Tips:
1) you can fill the drip tray with sand or crushed red brick to act as a heat sink to help regulate the temp swings.
2) Use disposable aluminum trays to make an impromptu stand, to hold the blade edge down/spine up oriented. And a cover for the blade to mitigate any direct heat flow. This will overheat your blade, causing it to be over tempered and be low on the hrc scale.
- Temper knifefor two or three 1 hour cycles,cooling with water between the cycles**
If you need to straighten any warps, take it from the oven when the second or third cycle is completed and while hot, mount it in your vice and give a slight push in the direction needed. If it is a biw, you might be able to just clamp it and let it cool with the vice jaws doing the straightening.

Don't forget, once you are filing and sharpening, you will have a layer that has had the carbon burned out and not able to be hardened. Once you are through this skin, you will have a hardened blade underneath.

Welcome to the forum, Good luck and keep us updated with pics.

 

[BC Bushcraft]

How are you going to be holding the knife?
How are you going to be quenching the blade?


The best you can reliably hope for is a differential hardening, like they do on Beckers. A soft tang and hardened blade.

You can do this, but you will need to set up as best you can prior to your attempt.
- At least one gallon of canola oil (2+ is preferred), this will need to be heated to 120°-130°. Heat a cheap piece of bar stock from a home improvement store with your torch and dunk it in the oil, reheat and redunk, over and over until brought up to temp.
- Check your oil temp with a meat thermometer or an IR one from harbor freight.
- I would hold the blade by the very end of the tang with a set of locking pliers (like vice grips) and clamp those to a table or workbench with a quick release c-clamp.
- within arms reach, you will want a magnet held in a set of pliers, you will need this to check your knifes temp. It will need to be mobile since your knife is clamped down.
- Run the torches back and forth, continuously moving, over the spine and flats area and let conduction bring the blade area up to temp.
- Once the blade is no longer magnetic run the torches for a few more seconds to bring it one shade brighter (this will offset the travel time of no heat to the oil).
- dunk your blade in the oil, tip first. Move the blade vertically and edge to spine to shed the heat as quick as possible (If you go side to side you risk warpage).
- Check with a file for hardness, it should skate and not bite too deeply (more on this at the end).

Hardening is done, tempering next.

- Once your knife cooled to being able to touch, you can check for warpage. If there is any, you will have to wait til the second or third temper to straighten.
- Preheat a toaster oven to 410°-420° and let it stabilize, use the meat thermometer to watch the temp.
Tips:
1) you can fill the drip tray with sand or crushed red brick to act as a heat sink to help regulate the temp swings.
2) Use disposable aluminum trays to make an impromptu stand, to hold the blade edge down/spine up oriented. And a cover for the blade to mitigate any direct heat flow. This will overheat your blade, causing it to be over tempered and be low on the hrc scale.
- Temper knifefor two or three 1 hour cycles,cooling with water between the cycles**
If you need to straighten any warps, take it from the oven when the second or third cycle is completed and while hot, mount it in your vice and give a slight push in the direction needed. If it is a biw, you might be able to just clamp it and let it cool with the vice jaws doing the straightening.

Don't forget, once you are filing and sharpening, you will have a layer that has had the carbon burned out and not able to be hardened. Once you are through this skin, you will have a hardened blade underneath.

Welcome to the forum, Good luck and keep us updated with pics.

Thanks for the reply, I would be holding the blade with locking vise grips at the end of the handle. Do you think I could instead mount in place the two torches and move the knife through where the flames meet? And does the temp of the canola quench matter a lot. If I simply heated a railway spike to cherry red and quenched then left it. Or should I really purchase a temp reader.

Im just trying to work with what I have but if I really need to buy some things I will.

 

[NJBillK]

As long as the blade is moving between the heat sources, and you don't cook the edge, you are fine.

You can use a rail spike, but it will take a few cycles of heating to get the oil to temp.
You will need the oil to temp otherwise you risk creating a gas jacket that will not allow the oil to contact the blade and not cool it fast enough. This will cause you to not get under the pearlite nose and thus keep the blade from hardening properly.

Plus you are going to want a thermometer for the tempering.
They can be found a few $, check a second hand store for one with a corded probe that you can leave in the oven.

 

[BC Bushcraft]

As long as the blade is moving between the heat sources, and you don't cook the edge, you are fine.

You can use a rail spike, but it will take a few cycles of heating to get the oil to temp.
You will need the oil to temp otherwise you risk creating a gas jacket that will not allow the oil to contact the blade and not cool it fast enough. This will cause you to not get under the pearlite nose and thus keep the blade from hardening properly.

Plus you are going to want a thermometer for the tempering.
They can be found a few $, check a second hand store for one with a corded probe that you can leave in the oven.

Cheers, I'll just buy something to read the heat instead of guessing. I want to make a few knives so I should just invest. The HT part is the what I'm most nervous for. I am not expecting super accurate stuff, just a hardened usable blade you know.

 

[NJBillK]

Yep, 1084 can make a completely serviceable knife with a home brew HT, as long as you do it to your capabilities and realize that once you start doing it, you will want to do more.

You will likely end up making a skinner, an edc, a bushcraft, something with a low heel and thin BTE for some kitchen use, maybe a parer, there are a bunch of options that open up once you are comfortable.

Why buy knives when you can make one built for Your hand?
Can't get much more custom than that, eh?

Again, welcome aboard. It's all down hill from here.

 

[BC Bushcraft]

Yep, 1084 can make a completely serviceable knife with a home brew HT, as long as you do it to your capabilities and realize that once you start doing it, you will want to do more.

You will likely end up making a skinner, an edc, a bushcraft, something with a low heel and thin BTE for some kitchen use, maybe a parer, there are a bunch of options that open up once you are comfortable.

Why buy knives when you can make one built for Your hand?
Can't get much more custom than that, eh?

Again, welcome aboard. It's all down hill from here.

Haha for sure, always something I wanted to do but thought it would be too hard without any machines. I'm already thinking about things to purchase to help my system! Thanks for the help really appreciate it.