Coffee etching??

K

K.G. Travis

Joined
Apr 15, 2018
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17
Hello! Im working on a chefs knife made with 1095 and as I am sitting here waiting on clay to dry for a hamon, I ran across something Ive never heard of before. Coffee etching! But I cant find much info about it. My question is does anybody here know if this will work on 1095 and will it bring out the hamon??
If so does anybody know the process and or how to make the coffee etching solution?
 
It creates a very black patina. Bad part is it will be useless on a chefs knife because it scratches and rubs off easily.

All you want or need on a chefs blade is a standard acid patina. After etching in FC/garlic/etc. clean up well and carefully polish the ha-gane with something like Flitz.
 
Stacy E. Apelt - Bladesmith said:
It creates a very black patina. Bad part is it will be useless on a chefs knife because it scratches and rubs off easily.

All you want or need on a chefs blade is a standard acid patina. After etching in FC/garlic/etc. clean up well and carefully polish the ha-gane with something like Flitz.
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Ok...good to know! I was planning on using vinegar,or A very diluted ferric solution and ran across the coffee thing and just thought it sounded interesting. Thanks for the info
 
It looks fantastic, it is just not durable on a user. Dave Catoe did a yataghan recently with it. It was jet black and shiny ... until he went to cut some stuff. It scratched and rubbed off easily.


Hopefully he will see this thread and post his method and opinion.
 
The first time that I saw instant coffee used as an echant was when the Dutch makers were using it as a final etch on damascus. It just makes the dark stuff darker and since many of them are using O2, that means REALLY dark.
 
jdm61 said:
Seen that and parkerizing. Coffee might be of a little less concern for a kitchen knife as food is generally "food safe."
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That's both what I've heard from folks I consider smarter than me (which covers just about everyone, the older I get), and it makes sense to me. Regarding Mr Travis initial post about not much info about coffee etching, there isn't much, mostly just threads like this one. Personally, I'd call it coffee staining, because even though it is a weak acid, I don't know how long it's take to actually etch the steel. I've posted before that another benefit that I see to the coffee is that it's safe to dunk the whole knife, handle and all in the coffee and get the darkening/contrast effect without damaging stabilized wood or ebony.
 
jdm61 said:
since many of them are using O2, that means REALLY dark.
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I've got good results with the O1 damascus I've done, not sure if I can see the difference between those and my 1095 knives, but the O1 was a san-mai,
and the entire middle layer got black,
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and haven't yet done a san mai with 1095. I'm curious to see how much contrast I get with my in progress 5160/15N20 knives. I'm guessing not much.
 
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valknut said:
From what I've read your supposed to etch in boiling vinegar then dip in coffee
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What I've read and do myself is etch in acid long enough to get enough of an etch that you can feel with your fingernail, then use coffee. I've also read that you should dunk in coffee for 15-20 min, but I found that 2-8 hours works. It depends on how strong you make your coffee (the stronger the better, I use 1/2 jar of the cheapest instant coffee I could find to 1/2 gal water. It also depends on temperature of the room/coffee (warmer works a bit faster). Again, the worst thing that will happen if you leave it in too long (I've done 16 hours once) is that the 15N20 picks up some of the staining and you have to re-sand to get a good looking contrast, and if you sand too much, you may have to repeat the staining process.
 
IIRC, Dave uses a small jar of the cheap house brand coffee in a gallon of boiling water. He soaks the blade overnight. I believe he etches the blade first in FC. I'll call him today and ask specifics.
 
Nice looking knife, drew. Your post reminded me of one other think Iv'e heard/read. The coffee darkens rough surfaces better than smooth, so sandblasting would be great. That's why I FeCl etch to get some topography first, so that I can then sand the 15N20 high spots to either 200g or 5000g (depending on my mood, mostly), then coffee dunk. I feel the san mai type blades are harder to get an even darkness because of the lack of topography.
 
drew1972 said:
This is a coffee etch. This blade was sandblasted, ferric chloride etch, instant coffee and stonewash. I left it in very strong coffee for about 18 hours.
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Great looking knife Drew!

Did you use WD40 in the stone wash? How many times did you repeat the SW? If so, did you recoffee between SWing sessions?
 
I've used black tea in combination with boiled vinegar. I steeped the tea in small amount of boiling water then added some hot vinegar. The tannin in the black tea supposedly helps darken more than the light grey of vinegar alone. This is a video I saw.
 
This is a cool trick. I've never heard of it mixing the tea with vinegar before. I've heard of using green tea (among other things) as a rust converter in Japan, and it works nicely.

What I'm not getting is the silicone spray before putting the blade in the liquid... All he says is that it's important for getting a consistent black on the blade. But how exactly does putting a resist on the clean steel help this? I would think it would prevent the patina from setting.
 
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