Coffee forced patina

N

n7titan

Joined
Jun 14, 2014
Messages
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Tried my hand today at putting a patina on the spine of my Esee4.
I tried bleach, brown mustard, and finally a cup of coffee.

The bleach didn't do too well, so I tried mustard and it came out with the usual blotchy patterns. I decided I didn't like it so I rubbed some sharpening stone slurry on it to polish off the mustard patina and tried again with coffee. I just filled a cup and put my knife in tip-down for about 40 minutes.
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Since I had the knife just sitting in a syrofoam coffee cup you can see how the very tip doesn't have any patina at all to compare to the rest of the spine. Total combined dunk time is probably about 2.5 hours.It gives a real nice even darkening effect on the 1095, like a gunmetal color. I also like how you can still polish this patina to make it shine more, it's not an aggressive corrosion like strong vinegar is.
I'll probably end up stripping more of the coating in the future and coffee darken the rest of the blade, this was just a test to see which I would like. An idea I have is to use it like normal and give it a coffee bath every time a good amount of the coating is scratched/falls off for a layered wear-pattern patina.

Sorry about the bad pictures, I just have my gopro on me. I'll post macro shots later.
 
Interesting. I don't think I've ever seen anyone use coffee before. Looks good dude. :thumbup:

I've always just used white vinegar, but I might have to try coffee, heaven knows I love to drink it.

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Better pictures
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The first picture shows what it looks like in good light.
The second is to compare the full patina against the relatively clean tip.
For the third, I had the blade rest in the cup so all of the spine was submerged but not all of the blade.
For the first hour or so the back end of the blade was never in the coffee and in the last hour I had the whole thing submerged. You can see on the right side a bit of splotching and a lighter coat but the left side of the blade is almost indistinguishable in darkness. It seems the coffee fades together "waterlines" pretty well into one even coat. I suspect the right side might have had some oil contamination from my rag or hands.
Also on the third picture you can see the effects my brown mustar had on the Rowen decal, Esee knives USA was the only one to get bleach and mustard. The bleach didn't seem to do much at all.
 
White vinegar has an average pH of 2.4 while coffee is around 4.9

Comparing yours and mine it follows that the compound that's more acidic dimples the metal more quickly/vigorously and the less acidic substance makes a lighter/smoother finish. The coffee patina probably isn't as durable as more acidic finishes though.
I quite like the coffee, I don't have to mess with smells or making the coating even.
I kept reheating the coffee to speed up the process. As a bonus it made the knife hot enough to evaporate moisture, making it easy to check it's progress with a quick wipe on a towel.
 
I don't think I've seen someone put a patina on a coated blade. I assume the effect is limited to the exposed metal only?
 
Yes only on the exposed metal. I ground a bit off the spine for flint striking (you can see the grind marks near the gimping) and decided to strip the whole spine and put on a patina. I don't know when, but I'll eventually take the rest of the coating off and do more.
 
How big a PITA is it to remove the coating, do you use sandpaper and elbow grease or do you really need a power tool?
 
The power tool was to try to get a 90 degree edge for firesteels, I barely touched it before I decided to take the rest of the spine off for looks. I used another knife and scraped for a few minutes till most of it was off, then I took another few minutes on a sharpening stone. Cutting into the coating was like trying to shave off slightly rubberized superglue.

^^ paint stripper or power tool definitely needed to make taking off "all" the coating easy.

Note: Thank you mods for moving the thread to the appropriate place, I didn't even notice when you moved it :D
 
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