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Steel blackening technique not working


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Hi Everyone,

 

I tried Mr. Brian Vanspeybroeck's technique on steel blackening, but it doesn't seem to work on my blade. I followed the steps: rusting(this worked perfectly), then boiling. The only thing I didn't follow is using distilled water for boiling. I used tap water instead. Was this the culprit?

 

By the way, I'm trying to blacken a hardened 5160 blade, instead of iron fittings which the original topic discussed(I can't find that post anymore).

 

I need your advice Mr. Brian Vanspeybroeck. Or if anyone else has experience with this, please pitch in.

 

Thanks in advance.

 

-shinobi

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you're not giving us a lot of info to go on. you're not getting the effect you want, but what effect are you getting? not turning black? rubbing off? we need more info. the only problem i've had with this technique is getting the layer of rust thick and even enough, while still adhering to the steel

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you're not giving us a lot of info to go on. you're not getting the effect you want, but what effect are you getting? not turning black? rubbing off? we need more info. the only problem i've had with this technique is getting the layer of rust thick and even enough, while still adhering to the steel

 

 

Hi Jake,

 

After boiling it for 10 minutes, the rusted blade did not turn black at all. It's still red rust. The thick rust is still intact, and after I let it sit in my shop for a month, I tried boiling it again yesterday, this time for 15 minutes. Still red rust after that.

 

If this doesn't work out at all, what do you think I should do with the existing rust on the blade? can I heat it up a bit and rub black beeswax on it? kinda like a texture or something. I don't want this blade shiny at all. It's supposed to be a tactical knife.

 

Thanks

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Hi Shinobi,

I think the elements that form solid solutions with iron (Phosphorus, Titanium, Tungsten, Vanadium, Chromium, etc.) make a different kind of rust that doesn't convert to magnetite when you boil it. Of course it does depend on how much of the alloying element is in the steel. Isn't 5160 like .7% to 1% Chromium?

 

Here is a picture of some of my .5% Phosphorus iron that's been rusted and boiled. In the white region the rust simply rubbed right off.

high Phosphorus rust.jpg

 

My experience is limited to low carbon alloys though. I'm very interested in the comments of the next guy who has made this work.

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I have no idea but I suspect that Skip may be on to something...perhaps the chromium in the 5160 is preventing it from going black. I dunno. :wacko:

 

With low carbon steels or iron it works very well but takes several (translation: *A LOT*) of rust/card/boil cycles to build up a credible amount of rust coating. This is the technique used many years ago to "rust blue" a firearm. You coat the metal with a solution that causes rust (lot of things like acids and salts will work) and hang it where is has lots of moisture and heat. The old firearm guys used a closet with warm wet sponges/cloths and let it rust for hours/days. Then they "carded" the rust. Essentially rubbing off the loose rust and polishing. Then you boil in water (I always used distilled water) until it turns black. Then you do it again...rust/polish/boil until you get a solid black surface which you then oil or wax while warm.

 

I have done some mild steel fittings out of 1018 that were waxed with Renaissance Wax (a very fine microcrystaline wax) right out of the last boil and they had the most beautiful glossy deep black color I have ever seen on steel.

 

But why you are not getting black after boiling I have no idea. Come to think of it I did do a couple knives a few years ago and rust blacked them and they came out looking very nice but I don't remember if they were 5160 or O1. Most likely 5160. Can you relay your exact proceedure and maybe we can collectively find a solution or cause? I'm a very firm believer in finding something that works for me and then bangin' the crap out of it...like a recipe. I always am a big stickler for proceedure and for consistency and only changing one variable at a time if I don't get the desired results. I use hydrogen peroxide and table salt and make a super saturated solution of peroxide and salt by heating the peroxide to boiling and adding salt (in a glass cup in the microwave) until it will dissolve no more salt.

 

Then I put the steel in a plastic (that can take the heat...like a soup bowl) cup and pour boiling (or very hot) solution on the steel until covered. I let it bubble and boil and get all rusted and then remove the piece and scrub it down with a toothbrush (use someone elses toothbrush as the stuff tasts terrible and turns everything orange :lol: ) using Barkeepers Friend or some Comet as a scouring powder on the brush. clean it up under running water and then rust it again with fresh, hot peroxide /salt solution. I'll rust and polish it maybe 5 or 6 times and then boil it till black. Then it's back to the peroxide and scrub routine for *a lot* of cycles. You'll know when it's done cause it'll have so much black stuff coating the steel that it'll stop reacting when you pour solution over it. By the way, choji oil mixed with BreakFree CLP makes a great finish and you need a good oiling or the final black will continue to eat the steel for days until it neutralizes itself.

 

But all the rust I ever boiled turned black on me after about 10 minutes. :(

 

Brian

Edited by Brian Vanspeybroeck
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i can get a black/ grey coating on my blades by de scaleing them in vinegar for a few days, then i wire brush off the scale and it is a dark grey/black that take some time with abrasivest to get off (by time i mean half an hour with coarse emery paper on a 3in blade)

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never done it on 5160, but i've done a couple of blades in O1 which blackened beatuifully. i would try boiling in tea if the water is not turning the rust black - the tannins may give it that extra push. if that doesn't work you could try painting the rust with gun blue.

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Yeah..O1 wants to go jet black like a MoFo. I like O1 a lot for this "making black blades"... B)

 

But I have done the black thing mostly on low carbon and A36 and iron fittings. If I think about it I can find a picture of some electrolytic iron fittings done this way. It was a hoot...so wonderful and natural. Pure iron does this very well. Low alloys? Well, we'll solve it if we can. ;)

 

Brian

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Brian,

 

My procedure was exactly like yours. I used a super saturated Hydrogen peroxide(20 volumes), heat it up and added salt. Then I shake it. I added more salt till no more will dissolve. Then added a an ounce of white vinegar. Then I warm the concoction again, and put it in a spray bottle. I sprayed the blade, let it foam up for about a minute. Then I rinse it. This cycle was repeated several times until it had an even coating of red rust.

 

I had no distilled water that time, so I just used tap water to boil the rusted blade.

 

These are progress pictures of the blade:

 

After draw filing

1.jpg

 

 

After the heat treat/oil quench

2.jpg

3.jpg

 

 

 

This is the blade after boiling

4.jpg

note: the this picture was taken a month after the blade has been rusted, and yesterday was my 2nd attempt at boiling it.

 

 

I thought of burning the blade with a blow torch, edge soaked in water. But it would take a lot of heat to oxidize the rust and turn it black. That will surely ruin the HT.

Edited by shinobituazon
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Man...that one will look cool black. Nice design for this concept. B)

 

I used the added vinegar and spray routine very early in my attempts and learned that the vinegar really didn't add a whole lot to the equation. Also, the immersion method gets a lot more even coating of oxide a lot faster than spraying. It's quite the violent reaction and if you soak/rust and the polish and then boil (I'd use the distilled water 'cause that is what I have always used) about 20 minutes you should get black rust. I have found that with some steels it helps to boil more frequently and very early in the process as layers of black rust beneath tend to make the next and othr subsequent layers darker/blacker.

 

If I were you, I'd polish this attempt off and start again fresh with a polished surface and try immersion in the peroxide/salt and *really* get a good layer of red rust the first soak. Then boil it and soak again and get some black under the next layers. This process is very labor and time consuming done correctly...it actually takes me more fussing the get the color than it does for me to make fittings. :wacko:

 

Also, little changes in proceedure make big changes in the quality of the blacking process. So get yourself a steel plate/blank of the same steel you are going to use and experiment and get your process down pat on a scrap piece of steel before you do the knife. I usually do the finish in one sitting even if that takes 5-8 hours to complete...which it frequently does. Get into a swing and do the rust/polish/boil routine over and over in rapid sucession. Like 3 cycles per hour.

 

I have backtracked online over this issue and simply can't find any reason your not getting the rust to go black. I have had it go very dark red/brown and settle into black after a few cycles but it always turns black for me. I have a small movie I found on my hard drive but I'm having a problem uploading it to my webspace. I'll try and get that setup as it kind of explains things better.

 

Brian

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  • 1 month later...

Shinobi,

 

Ive never tried the rust and boil method but here is what I do to blacken blades.

 

1. etch in FeCl for 20 min, rinse and clean up, repeat twice.

2. gun blue after cleaning up the acid etched gunk

3. Boil in oak, maple leaves for three 45 min cycles

4. rub with steel wool and repeat step 3 once more.

 

this has given me a rich dark black color every time Ive used it, its a bit overkill but it does work well.

 

* for non carbon steel just hot blue then gun blue for a dark finish*

 

Hope this helps you

 

Pat B

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  • 1 month later...

i have done rust bluing with with 5160 using rainwater, it worked fine for me.

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  • 2 weeks later...
  • 2 weeks later...
With low carbon steels or iron it works very well but takes several (translation: *A LOT*) of rust/card/boil cycles to build up a credible amount of rust coating. This is the technique used many years ago to "rust blue" a firearm.

 

I have an old recipe for the original rust bluing on firearms, but it does not give you the "Black" color that modern hot-blued guns have. This produces a true "blue", and while continous applications will deepen it, it will not turn black.

 

Specialty gunsmiths still use this method for restoring double barrel shotguns because the heat involved with a modern salt tank is high enough to cause the solder holding the barrels together to fail.

 

1 pint Nitric acid

1lb uncoated steel nails (original recipe calls for Iron nails)

 

In a suitable (acid proof) oversized container, dump the nails in first, then carefully add the acid. This will cause an eruption of brown fumes that looks like the "stacks" on an 18-wheeler pulling a steep hill, so you definitely want to do it outside, and stay well away from it. The reaction is violent, so proper protective gear is a must.

 

The nails will reduce to sediment, and after allowing the sediment to settle, pour off the resulting "cut" acid into a permanent container with a tight sealing lid.

 

Make sure your part is totally degreased and clean, then brush on the solution, making sure everything "wets". Allow the excess to drip off, then hang the part in a humid environment, like a basement or celler (gunsmiths use a "humidity cabinet" to speed up the process). A light coating of rust will develop, usually overnight. This needs to be carded off with degreased 0000 steel wool, followed by an immediate fresh coating of cut-acid. This has to be repeated many times, but it will give you the original true-blue that you see on old firearms.

 

One thing to note if you try this is don't forget about the part. Leave it too long and it will leave pits in the metal instead of the light, "dusty" rust coating that you want.

Edited by S. McGrath
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