Blue Damascus Project

the way it is paterened it looks more like a splash anodized Aluminium.

how the heck did it come out blue on parts but pure silver on others? either way super awesome
-matt
 
I have wondered the same SR matt, every time I see a blued damascus blade it is at least 2-3 colors. Do the different steels react to the blue differently?
 
That looks a lot like niter blueing. It's done with heated salts (about 600F). It is not a chemical process like typical gun blueing. The heat is what makes the color ... not unlike how you get blue, purple, etc. on a motorcycle pipe when it's run for a while, but in this case, you can control the exact shade and it's an even application.
If one alloy is high-nickel or if there is pure nickel, it will come out bright and look a lot like this, while the carbon steel turns that color blue. This is probably 1095 and nickel or something like that.

Brownell's sells a kit.

The problem with doing this to a knife is that that great blue color comes on about 550F or so. That going to make for a softer knife.
 
JCaswell said:
The problem with doing this to a knife is that that great blue color comes on about 550F or so. That going to make for a softer knife.
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I understand what your saying but the last stage of hardening/tempering a blade is to take the metal to temperature (usually about 600F) for 20 minutes, depending on the metal. On certain types of Damascus (because each uses different blends of metals) you can achieve a very bright blue (like the one pictured) if you take the metal to a very closely monitored 550 - 575F. If done just the right way, on the final tempering process, you will have a very hard & very blue blade, of course all things concidered.
JCasewell did say "softer" blade and he is very right because everything needs to be just right or you can wind up with a soft knife.
Respectfully said and by no means trying to say JCasewell was wrong.
Only showing a possible method that may have been used depending on the metals in the Damascus, since it was not listed in the post.
Always best wishes to all
 
Sysop said:
I understand what your saying but the last stage of hardening/tempering a blade is to take the metal to temperature (usually about 600F) for 20 minutes, depending on the metal. On certain types of Damascus (because each uses different blends of metals) you can achieve a very bright blue (like the one pictured) if you take the metal to a very closely monitored 550 - 575F. If done just the right way, on the final tempering process, you will have a very hard & very blue blade, of course all things concidered.
JCasewell did say "softer" blade and he is very right because everything needs to be just right or you can wind up with a soft knife.
Respectfully said and by no means trying to say JCasewell was wrong.
Only showing a possible method that may have been used depending on the metals in the Damascus, since it was not listed in the post.
Always best wishes to all
Click to expand...

Most guys temper down around 400F. 600F is pretty high for a carbon steel knife. If this is 1095, for instance, the difference would be ~58Rc vs. ~52Rc.
 
The maker has added to his post. 572-575F is what he says he tempers to. My admiral 0-1 says 600F will temper to 52-56 which is pretty broad but 575F might make it 56 or higher. I'm curious how the damascus would differ.
 
Mark Pointen said:
The maker has added to his post. 572-575F is what he says he tempers to. My admiral 0-1 says 600F will temper to 52-56 which is pretty broad but 575F might make it 56 or higher. I'm curious how the damascus would differ.
Click to expand...

My ASM atlas of iso transformation TTT diagram shows 600F would produce 49Rc in O-1, 56 Rc @ 500F.

Anyway you slice it, it's sub-optimum hardness for a knife IMO. I can't see sacrificing steel performance for a pretty blue finish.
 
correct me if i am wrong but quickly taking a metal to a high temp (i.e. not letting it soak in that temp) will still color it wont it? i know you can hit metals with a torch quickly and color them (i know if they are thin it can soften them some but not a whole lot).

basicaly what im trying to get at is how long does a blade really need to be soaked at to temper it down VS the lenght it has to be soaked to color?
-matt
 
SR_matt said:
correct me if i am wrong but quickly taking a metal to a high temp (i.e. not letting it soak in that temp) will still color it wont it? i know you can hit metals with a torch quickly and color them (i know if they are thin it can soften them some but not a whole lot).

basicaly what im trying to get at is how long does a blade really need to be soaked at to temper it down VS the lenght it has to be soaked to color?
-matt
Click to expand...

The niter bluing process requires the part be submerged in the hot salt for a duration sufficient to heat the part through. Typically, you level the salts off at 600F, dunk the part and watch the colors turn from straw, purple then blue--too far makes a dingy gray. (It's best to run the salt slightly higher than your target temp so the part doesn't languish at a particular stage unnecisarily.) The part is fully soaked in this process. When you hit the color you want, you pull it and quench it. (I've done a load of gun parts this way in the past.)

It's not a primarily a surface treatment. It's a tempering operation. As such, it's actually a plus that these small parts are heated through before the color signature is achieved. It's a pretty dependable way to know the part is properly tempered.

This process is historically used for tempering. You will see it used on old gun springs and screws and sometimes for tempering the tang/forte area of swords. You can see this on fine old 18C production swords. It will show up as a blue field that just sort of rudely starts just above the hilt as if it was used to stir a can of blue Dyechem or something. Sometimes you will see it used further up the blade on presentation pieces to offset gold inlay/plating.
 
"My ASM atlas of iso transformation TTT diagram shows 600F would produce 49Rc in O-1, 56 Rc @ 500F.

Anyway you slice it, it's sub-optimum hardness for a knife IMO. I can't see sacrificing steel performance for a pretty blue finish."



Thanks J. I agree , thats too soft for performance.
 
Mark Pointen said:
"My ASM atlas of iso transformation TTT diagram shows 600F would produce 49Rc in O-1, 56 Rc @ 500F.

Anyway you slice it, it's sub-optimum hardness for a knife IMO. I can't see sacrificing steel performance for a pretty blue finish."




Thanks J. I agree , thats too soft for performance.
Click to expand...

Mark Pointen said:
The maker has added to his post. 572-575F is what he says he tempers to. My admiral 0-1 says 600F will temper to 52-56 which is pretty broad but 575F might make it 56 or higher. I'm curious how the damascus would differ.
Click to expand...

I read that whole blue Damascus project, if you read it all (not a bad read, a little long) but the maker says he takes the blade to 450F in the last sage of tempering, he caught his type-O when he re-read the tread.
Anyway, This would make the blade about a 57-58 rc if I 'am not mistaken, does anyone know for sure because I was going to try a blue blade to see the out come and would like any input.
Thanks.
 
Ive done similar with bolsters but not a hardened blade.

Bolster:
2.jpg


I did it by etching, then hitting it with 1200 grit paper, then heat bluing. The Nickel stays silver while the steel gets blue. Im assuming he did the same, but like others said, the temper range seems high.
 
pKc said:
I read that whole blue Damascus project, if you read it all (not a bad read, a little long) but the maker says he takes the blade to 450F in the last sage of tempering, he caught his type-O when he re-read the tread.
Anyway, This would make the blade about a 57-58 rc if I 'am not mistaken, does anyone know for sure because I was going to try a blue blade to see the out come and would like any input.
Thanks.
Click to expand...

He's not getting that blue at 450F. That blue starts at about 550F or a bit higher. This darker blue hits around 570F and can remain until about 600F. A little over that and it all turns dingy gray.
If he's talking about a final temper at 450 after it's blue, I'm not sure what that would accomplish.
 
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