Photos A Metallurgical Question for Intended Knife Mod. PICS ADDED

[LoneWolf X]

I'm in the process of doing some minor mods to a BK-9 and before proceeding I need some knowledgable and experienced advice. Namely, I'm planning on refinishing the blade with a cold blued or maybe a rust-blued process.
In doing the cold bluing I have in mind it's been recommended to heat the steel somewhat before applying the blue to promote a better result, eg: 150F-200F in oven or by heat gun; with the rust-blue method the blade would require multiple sessions of soaking in boiling water for 20-30 minutes per session.
Is there any possiblity of negatively affecting the factory heat treat temper of the knife by either of these heating actions?

I've already electro-etched the blade markings, stripped the epoxy coating and sanded the blade grinds to my liking- just waiting to get advice before proceeding now to the actual finishing work.

 

[91bravo]

You won't need to heat up the steel for cold bluing. I've done it many many times with room temperature steel and the bluing took very well. This is with knife and gun steel as well.

 

[Crag the Brewer]

Also those temps are nothing for the steel... it won't affect the heat treating at all.
I'm sure your Niner will see that as just taking a bath....

 

[bearfacedkiller]

You would probably need to be at at least 350 to change the temper.

That said, just do it at room temperature. It is called cold blue.

 

[daizee]

You'd need to break 450F to come close to softening 1095CV that's already at 58Rc.
That said, leaving the blade touching (tip or flat) the bottom of a bot of boiling water might get it to unknown temperatures, whereas placing in in a steamer basket in the boiling water would be perfectly safe.

 

[LoneWolf X]

Thanks for the sage input guys; exactly the insights I needed.
I also have the Ferric Chloride needed to do that method of surface finish as well but am leaning toward the bluing. I plan on doing it in the next day or two- I'll try to post pics of the final outcome when completed.

 

[Shotgun]

Also, pics or it didn’t happen.

 

[LoneWolf X]

It happened!

I've always favored a black blade but the factory epoxy coat doesn't facilitate uses with the blade such as ferro rod striking and I have a few knives with a factory hot-blue finish, which I think looks fantastic on a knife, hence my decision to try a strip and cold bluing on one of my 9's.
The blue I used is Brownells's Oxpho-Blue. It took about eight coats to achieve the depth of hue I wanted and I ended up having to re-sand the upper flat portion of the blade to get the same consistancy with the lower saber portion- turned out I had sanded it too smooth and the blue wouldn't take well enough on it to get the blacker depth.
I was somewhat surprised to find just how rough the steel finish actually is beneath the epoxy coat; the upper flat grind sure had some heavy pits in it. The degree of sanding I finished with removed about 50% of them but I'd have had to really do some serious surface removal if my goal were to have a mirror smooth finsh.

I really like how it turned out. Too bad the blued finish isn't more durable; just running it through the K.O. Worksharp to rehone the edge left some noticable abrasions to it.

 

[DerekH]

Oooooh that's niiiiiice.

 

[bearfacedkiller]

I like it. Who cares if it isn't durable? It is easy enough to reblue it.

Thanks for sharing!

 

[Tanker 1/66]

It happened!

I've always favored a black blade but the factory epoxy coat doesn't facilitate uses with the blade such as ferro rod striking and I have a few knives with a factory hot-blue finish, which I think looks fantastic on a knife, hence my decision to try a strip and cold bluing on one of my 9's.
The blue I used is Brownells's Oxpho-Blue. It took about eight coats to achieve the depth of hue I wanted and I ended up having to re-sand the upper flat portion of the blade to get the same consistancy with the lower saber portion- turned out I had sanded it too smooth and the blue wouldn't take well enough on it to get the blacker depth.
I was somewhat surprised to find just how rough the steel finish actually is beneath the epoxy coat; the upper flat grind sure had some heavy pits in it. The degree of sanding I finished with removed about 50% of them but I'd have had to really do some serious surface removal if my goal were to have a mirror smooth finsh.

I really like how it turned out. Too bad the blued finish isn't more durable; just running it through the K.O. Worksharp to rehone the edge left some noticable abrasions to it.

Nice!!!!

 

[Tanker 1/66]

LoneWolf X Put blue painters tape on the flats of the blade before running it thru the KO

 

[LoneWolf X]

LoneWolf X Put blue painters tape on the flats of the blade before running it thru the KO

Yup, I knew that Tanker... just got in too big a hurry to bother to take the extra 60 seconds to do it.