Black echant

S

Steve Beckwith

Joined
May 29, 2004
Messages
391
A friend has supplied me with a piece of damascus from Baker Forge for a custom build for him. He wants a black etch on the 1084 in the mix but balks at buying a gallon of Gator Piss from Baker Forge. I have in the past used lemon juice, ferric chloride or heated vinegar to etch the few damascus pieces that I have used or to etch a hamon in a piece of W2 and always hade an etch that came out somewhere on the gray scale. Any suggestions for a jet black etch would be appreciated.
 
I had success with Ferric chloride cut with white vinegar, repeated etches. I found that after the final etch, spraying it down with a water displacing oil (WD-40) seemed to "set" the darker oxides better than immediately wiping it down. I sprayed the blade down and hung it up over night to set in. Not sure if that's the "right" answer but it worked for me.
 
I did some steak knives in ferric, cut with vinegar. After three cycles they were a decent contrast, but more gray like you describe. I mixed up super strong instant coffee and left it over night. They turned amazingly black. I can wash and scrub them quite vigorously and it doesn't come off. It seems to really set the oxides, not just a coffee stain. You have to see it to believe it. I've got some carnauba wax to put on like Royer does.
The first shot is one knife before the coffee and the second is all five after coffee.
PXL_20241204_231132014~3.jpgPXL_20241207_212400316~3.jpg
 
What is the ratio to ferric chloride, vinegar and water? And I have read about a coffee etch. I'll give that a go also.
 
I use 1/4 commercial FC etchant, and 3/4 vinegar. I do 3 etches, 8, 10, and 12 minutes, lightly sanding after each. For the coffee I filled a jar close to 1/3 full of instant powder, added hot water and put the knives in for 24 hours.
 
52100 after several 30 minute soaks in dilute Ferric Chloride:
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1085/15N20 in Gator Piss:
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I like that Gator Piss will etch dark quickly, but the surface is still fairly smooth. Ferric seems to leave rougher oxides/surface to the steel to get the darker colors, which can impart a lot more friction when cutting, particularly in kitchen knives. I haven't tried coffee etching yet to darken it and have been happy with the Gator Piss or Ferric Chloride. I was shocked at how well and quickly Gator Piss etched damascus compared to Ferric Chloride I used to use! A gallon will last a very long time!

I use WD-40 or Mineral oil and let the blades sit for a while after etching. Some people bake them or use a heat gun to warm them up to get the oxides to set better/quicker so they don't rub off as much with a paper towel, too. So many different ways to get good results!
 
After etching in FC, give the blade a 30-minute boil in a pan of water with 1Tsp of baking soda. That sets the etch well and neutralizes all acids. Rinse well and dry in the kitchen oven at 250°F for 30 minutes or use a hair dryer. Oil with a light blade preservative oil while warm and let cool before wiping off the excess.
 
Instant coffee like others have said, post etch. Make it VERY strong. I leave my blades in over night. This one below is 1095 CuMai, came out jet black. Just remember to neutralize after each step (etch and then coffee).

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If that was directed to me, I have a 50w fiber laser so I laser it after the coffee soak with settings that provide me a silver mark, in contrast to the blade.
 
Alex Topfer said:
Why is this? Does the retained austenite not etch as dark?
Click to expand...
It’s the carbon in solution and the tempered martensite. Carbon is what’s left on the surface after etching.
Fresh martensite does not etch, only tempered martensite.

Hoss
 
I like to use FC so the dark areas are lower/deeper than the brighter ones, then you can use high grit paper to pop the bright areas for the best contrast.
Dunno how is called in the US but I use here a product called fosfatizante (phosphatizer?) that needs to be used at boiling temperature, it darkens carbon steel beautifully. I use it after the FC bath explained above.

Pablo

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