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Keeping etched blades "black"


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Putting a fish tank bubbler in the etch tank helps speed the etch by agitating the acid. It helps knock the oxide layer off. Cold blue works better when applied hot, or at least warm.

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Just don't get mixed up to the point that you drink your ferric chloride instead of your coffee!   

Hello all.  I, too have moved to the coffee for final darkening.  I do the normal technique for etching using FeCl, but then before oiling the blade, I do a 12-24 hour dunk in cold, extra strong coffe

Hahahaha. "When I said that I wanted to recreate a blade I saw in a museum, I meant "as it looked when it was new" not "as it looked when it was dug out of the ground".

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That helps, and I always etch at least ten minutes, usually 20 or 30 minutes in several cycles.  If you want the contrast you need the topography! 

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On 4/21/2018 at 9:34 PM, Gene Kimmi said:

Something else you can do after etching in ferric, is soak the blade in really strong instant coffee.  Here is one I that I soaked for about an hour.

This is the method that JJ recommended to me, which I used yesterday to etch a knife.  I did five 10 minute soaks in Ferric, with some light sanding between soaks, followed by a 5 hour soak in super strong instant cold coffee.  It worked really well, or at least I think it did.

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On 4/30/2018 at 10:47 AM, Joshua States said:

Putting a fish tank bubbler in the etch tank helps speed the etch by agitating the acid. It helps knock the oxide layer off. Cold blue works better when applied hot, or at least warm.

Is this not attacked by the acid?  Or are you using a different type of bubbler then I have seen . The one I have in my fish tank is a plastic base with some type of porous stone set into it .....

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5 hours ago, Jonathan Silas said:

Is this not attacked by the acid?  Or are you using a different type of bubbler then I have seen . The one I have in my fish tank is a plastic base with some type of porous stone set into it .....

Don't get a submersible type. Get one that is meant to sit outside the tank and bubble through a hose like this one.

Then set it up next to the acid tank, cut enough hose to reach almost to the bottom (the oxides settle on the bottom and there's no sense in stirring them up), and make a weight to hold the hose down. I slotted a scrap of 1/8" 416SS and slid the hose end through it.

Bubbler (4).jpg

 

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Obviously  pretty late to this discussion, but I notice from your first photo a bit of pitting. This leads me to believe you have your FC/Water ratio too high.

How much have you diluted your FC? If the FC is too strong it will pit and not produce a clean contrast.

4 to 1 distilled water to FC is my ratio, and I etch for 2-4 cycles of 15 minutes.  I then clean with windex to neutralize, scrub under water and abrasive cleaning powder to remove all oxides (Comet is the brand in the US), and buff with pink, scratchless rouge.

I get pretty good contrast on my blades using this technique.

I pretty much only use a 10xx/15n20 PW mix, so if your steels are different YMMV.

Luck.

On 4/30/2018 at 7:42 AM, Alan Longmire said:

That helps, and I always etch at least ten minutes, usually 20 or 30 minutes in several cycles.  If you want the contrast you need the topography! 

What Alan said. Topography.

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My method is almost identical to what Dave just described except after neutralizing I Flitz the heck out of it.  If the etch was sufficiently deep it makes for a beautiful, long lasting finish... It can be difficult to photograph though.

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On ‎5‎/‎2‎/‎2018 at 6:44 AM, Dave Stephens said:

Obviously  pretty late to this discussion, but I notice from your first photo a bit of pitting. This leads me to believe you have your FC/Water ratio too high.

How much have you diluted your FC? If the FC is too strong it will pit and not produce a clean contrast.

Ehm, I should perhaps dilute it a bit then - seeing as it is pretty much pure. :lol:

Thanks for the tip man.... I will definitively do that ^_^

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3 hours ago, Alveprins said:

Ehm, I should perhaps dilute it a bit then - seeing as it is pretty much pure. :lol:

Thanks for the tip man.... I will definitively do that ^_^

It's a very common mistake. Four parts distilled water to one part FC is the trick. Luck!

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  • 1 month later...

UPDATE:

Alright, so I've done a 1 to 4 parts FC to water mixture, and this is a 5 minute soak:

Vethfolfnir-4.jpg

This blade is forged from the exact same billet as the previous blade, and I suppose one could say that the difference is .. well, significant. :)

I still don't understand how you can do several 15 minute or 20 minute soaks though. After only 5 minutes in a 1 to 4 mixture, this blade is already etched so deep I can feel the grooves with my fingers... :lol:

The whole thread in Show and Tell for this new one can be found HERE.

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Remember the principle involved. The etching creates topography the staining, by whatever method, darkens everything. The very, very light polishing with a rigid polishing method "shines" the high points of the topography, without levelling them out, leaving the low points stained hence the contrast. Easy to get lost in the process and lose the principle.

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I suppose the reason I do long etches is because my ferric chloride needs replacing, it's about exhausted after 14 years or so and no telling how many blades.  It will show colors in ten seconds, but it takes a long time to get good topography.  I need to factor that equation into future responses lest someone checks a blade in their new, hot FCl after an hour and finds a mere skeleton! :ph34r:

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Hahahaha.

"When I said that I wanted to recreate a blade I saw in a museum, I meant "as it looked when it was new" not "as it looked when it was dug out of the ground".

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  • 2 weeks later...

Hello all.  I, too have moved to the coffee for final darkening.  I do the normal technique for etching using FeCl, but then before oiling the blade, I do a 12-24 hour dunk in cold, extra strong coffee (I made mine with about 1/2 lb of the cheapest coffee I could find to 1/2 gal water.  Have been using the same coffee for the past 1 1/2 years. 

I do the coffee because: 1) I can teach customers the method and they can (and have ) re-darken the blacks after use on kitchen knives, and 2) you can re-darken with the handle already on (well with stabilized blocks anyway).  

Here are some examples:    #1,2,5 are 1095/15N20 #3&4 are O1/15N20.

23.jpg

21.jpg

22.jpg

17a.jpg

18.jpg

 

as always

peace and love

billyO

Edited by billyO
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9 hours ago, billyO said:

Hello all.  I, too have moved to the coffee for final darkening.  I do the normal technique for etching using FeCl, but then before oiling the blade, I do a 12-24 hour dunk in cold, extra strong coffee (I made mine with about 1/2 lb of the cheapest coffee I could find to 1/2 gal water.  Have been using the same coffee for the past 1 1/2 years. 

I do the coffee because: 1) I can teach customers the method and they can (and have ) re-darken the blacks after use on kitchen knives, and 2) you can re-darken with the handle already on (well with stabilized blocks anyway).  

Here are some examples:    #1,2,5 are 1095/15N20 #3&4 are O1/15N20.

as always

peace and love

billyO

Hi Billy, do you have problems with mold growing on top of your coffee mix?  Whenever I try to keep an instant coffee mixture for more than a couple of weeks I get a nasty cap of mold on top.

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3 hours ago, Brian Dougherty said:

Hi Billy, do you have problems with mold growing on top of your coffee mix?  Whenever I try to keep an instant coffee mixture for more than a couple of weeks I get a nasty cap of mold on top.

Don't know about Billy but I just had to throw a petri dish out the back door the other day. I have a container I used setting on my bench. The other day I walked by it and something caught my attention. When I opened it. There was mold spores all on the surface. I thought about just trying to skim it but decided to go ahead and dump it!! The way I figure it, anything I put in the mix is probably gonna kill the acid in the coffee that does the work! However I seem to remember something about citrus acid being added to something to keep it from molding. I watch the food channel sometimes at night! LOL

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Hi Brian, no problem with mold as of yet, but I do keep my jug in the refridgerator and it's set pretty cold.

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Yep I have decided that is the trick, refrigerate between uses! I guess given the temp of my shop this time of year, its lucky it wasn't walking and talking before I say the mold! LOL

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  • 3 weeks later...
4 hours ago, Gerhard said:

Does real coffee work or only instant?

You know, I have wondered this, but haven't tried.  As I understand it, instant coffee is just dehydrated real coffee, so I would expect it to work.  I don't drink coffee, so I never have it around the house to try.

Can someone dunk a scrap of pattern welded steel in their morning coffee cup and let us know what happens?

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I actually plan on dunking some blades in coffee this weekend so I'll let you all know how it turns out

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9 minutes ago, Brian Dougherty said:

instant coffee is just dehydrated real coffee, so I would expect it to work.  I don't drink coffee,

:lol: If you did drink coffee my reply would be "just keep telling yourself that"

I drink too much of the stuff, prefer dark roast, black no milk or sugar......Organic Honduras currently. I'll give it a try this afternoon.

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2 minutes ago, Gerhard said:

:lol: If you did drink coffee my reply would be "just keep telling yourself that"

I drink too much of the stuff, prefer dark roast, black no milk or sugar......Organic Honduras currently. I'll give it a try this afternoon.

:D  Yeah, I didn't mean to imply that it tastes the same, only that it should have the same chemicals in it.

On rare occasions, I'll be really dragging in the afternoon, and I'll pull a shot of espresso at the office.  (One of the other engineers is a coffee nut, and keeps a full auto machine in the break room at work)   If I did drink coffee regularly, I would drink it the same way you do :)

 

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That is what I was doing was if I had coffee left in the pot in the morning. Instead of dumping down the drain, I put it in a container long enough to do about a 10" blade. However I found out the coffee sitting on my workbench in the heat of Florida was a good idea only if you wanted to grow mold. Put it in the fridge and warm it up when you are ready for use.

You ever walked into a store and picked up the pot and you see the colors in it when you pour the last out of the pot. That is the natural acid in coffee and that is also what does the blackening. To keep it black I have heard of using a cold blue as a  topcoat so to speak. Although any bluing, browning or etch is only skin deep.

Someone was telling me about doing an etch using a battery charger. I will look to see if I can find the info!! 

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