Treating carbon steel Damascus after etching .

[Salem Straub]

Coffee finish is another method of etching or blackening otherwise etched steel. Some go right into coffee from a hand sanded finish, and etch outright in it, getting a little depth and good contrast in one process.
I like to etch pretty deep on my blades, for a higher contrast with more durability. So, I first etch in ferric chloride to get to the depth I like, and then neutralize and go into coffee for 3-4 hours.
The coffee used is nothing you'd want to drink. Instant works best, as it's got a real acidity with nasty tannins, which are great for industrial uses and not so much as a beverage. You mix it up strong, I use Great Value instant in the quart size jars, and use one of those per gallon of water. I simmer the water, stir the coffee in, cool it down, and use it as an etch cold. Some etch in it hot, but since it works for me cold, the process is a bit simpler and the evaporation rate of the mixture is way less. You can re-use it many times, although store it in the fridge or at least a cool dark place between uses.
What I've noticed about it is this... it's not quite as durable as parkerizing, if you're sanding with 2000 at the end to brighten the highs for contrast. It really works well if after the ferric etch you sand the highs until good contrast is achieved, and then go into the coffee with the blade already looking pretty good. The lows will blacken more, and the highs will stay shiny, so sanding after coffee will be minimal and in some cases not even necessary. That will help to preserve your nice black areas, especially on blades with bold pattern.
Warm and oil. I prefer coffee finish on kitchen knives, as it's a food after all- other blades still get parked. Kitchen knives get coconut oil rubbed on to finish, others get turbine oil or sometimes ren wax.

 

[Frank Niro]

Thank you all !
Frank

 

[javand]

Coffee finish is another method of etching or blackening otherwise etched steel. Some go right into coffee from a hand sanded finish, and etch outright in it, getting a little depth and good contrast in one process.
I like to etch pretty deep on my blades, for a higher contrast with more durability. So, I first etch in ferric chloride to get to the depth I like, and then neutralize and go into coffee for 3-4 hours.
The coffee used is nothing you'd want to drink. Instant works best, as it's got a real acidity with nasty tannins, which are great for industrial uses and not so much as a beverage. You mix it up strong, I use Great Value instant in the quart size jars, and use one of those per gallon of water. I simmer the water, stir the coffee in, cool it down, and use it as an etch cold. Some etch in it hot, but since it works for me cold, the process is a bit simpler and the evaporation rate of the mixture is way less. You can re-use it many times, although store it in the fridge or at least a cool dark place between uses.
What I've noticed about it is this... it's not quite as durable as parkerizing, if you're sanding with 2000 at the end to brighten the highs for contrast. It really works well if after the ferric etch you sand the highs until good contrast is achieved, and then go into the coffee with the blade already looking pretty good. The lows will blacken more, and the highs will stay shiny, so sanding after coffee will be minimal and in some cases not even necessary. That will help to preserve your nice black areas, especially on blades with bold pattern.
Warm and oil. I prefer coffee finish on kitchen knives, as it's a food after all- other blades still get parked. Kitchen knives get coconut oil rubbed on to finish, others get turbine oil or sometimes ren wax.

Not much to add, Salem summed it up pretty well. Definitely store in the fridge or it'll grow some nasty stuff on top, that you can never seem to fully skim, and cause some oils to form on the top that'll affect your etch evenness later.

Warm solution works potentially much faster, but it's easier to go too far, once you notice some discolorations on your silvers, you're pretty much stuck sanding it back in my experience, nothing extreme, but you'll be attempting to repeat the process from the last ferric etch at a minimum.

 

[Frank Niro]

Okay. Thanks.
Frank.

 

[weo]

I was taught to wait overnight before polishing after neutralizing in boiling water. Is this necessary?
Also, I was taught that Parkerizing is not for kitchen knives?

 

[javand]

I was taught to wait overnight before polishing after neutralizing in boiling water. Is this necessary?
Also, I was taught that Parkerizing is not for kitchen knives?

There are some schools of thought about "setting the oxides" I've had mixed results with this. Some leave the blade soaking in oil overnight and swear this helps.

There's some contention as to whether parkerizing or hot bluing is food safe. In either case I don't believe they're approved for kitchen use, regardless of whether they may or may not be actually safe.

I think one of the concerns with parking is the fact that it leaves a microporous surface, which is great for retaining oil, but retained oils in food prep can lead to rancidity and contamination.

 

[Horsewright]

Frank here is a whole nuther thought. Its worked for me pretty darn well but in a somewhat limited usage. Well enough that I want to explore it further with some of my other damascus blades. I make a lot of these little guys, 5.25" oal, The Vaquero Ultralite.

When developing the original prototype I was concerned about the handle area suffering from rust/etc. Basically sweaty palm syndrome. My solution was to give the whole knife a couple of light coats of Deft Clear Wood Finish spray, in satin. I had in on hand and had been using it and was well pleased with its performance on elk when I dye and process sheds into scales. I'd been using it for years on the elk and it occurred to me that the situation was kinda similar. I was trying to protect the lows, keep the color down in the texture of the elk and thats the same thing we're talking about here with the dammy. So anyhoo it works pretty darn good. Not something I'd do on a kitchen knife probably but otherwise it works pretty darn good. I've only done this to my Vaquero Ultralites. I can't tell ya why I haven't done this to my other damascus blades, I really do need to try it there too. Here is the prototype after 3.5 years of constant EDC service. If it wasn't in my hand being used it was in its leather crossdraw sheath on my belt. I run a cattle ranch besides all the jobs that this little guy got called to do in the shop, so it got plenty used. Never any flaking or peeling of the spray finish. The only rust was definitely my fault. I'd castrated a calf and half assed wiped the blade down on my leggings before putting it back in the sheath. Couple days later I pulled the knife out to cut something and noticed a small area where I'd left some blood on it had rusted. Little quick wet sanding with a drop of gun oil and 2000 grit paper it was all fixed.

Ain't saying this is the be all end all, just tossing it out there as a nuther thought.