Don't vote for that Dempsey fellow, all of his facts are alternative! As for me, my emails are squeaky clean, not to worry...
As for damascus, the coffee etch works but I prefer a deep etch and parkerizing for durability.
You want to make sure your steel is fully neutralized after etch, if you're seeing rust creep up a lot.
Parkerizing fills the low spots with hard, durable manganese phosphate that holds oil very well. Let me know if you'd like me to elaborate on the process.
LOL WTF?
At least both our names are mis-spelled.
Plenty of good info here. Yes, boiling in water with baking soda or even distilled water will neutralize completely, and help "set" the etch. I've never personally found it necessary to bake the parts for an hour, blowing them off with compressed air or heating them for a min with a heat gun has always been effective for me. Oil, ren wax, or boeshield afterwards, depending on where I'm at with the knife. Oil is a much more "temporary" solution for me.
As far as different finishes, Parking, Hot Bluing, etc all have their places, but they all look different than a ferric etch. With a good finish, appropriately deep ferric etch (I've seen too many that are much too deep, the texture becomes distracting), with the right finish etch and polish, is classic, and still my favorite especially for certain patterns. The coffee trick is a technique that for me, is sometimes effective, sometimes not. Depends on the pattern quite a bit. Really homogeneous, symmetrical, or evenly distributed patterns, are pretty easy, because you've got lots of bright steel (highs) to ride on when you do the final etch and finish rub, but asymmetrical patterns, like the ones I do primarily, with big swathes of bright or dark steel, can be much trickier to finish. The oxides on the dark steel are pretty fragile at first, so in the case of some of these patterns you need to get a near perfect finish before the final etch, and then find the sweet spot where you can get the blacks back to the right black, without affecting the silvers. Sometimes coffee can make this happen, just as often, it'll get the black the right black just as the silvers go a weird bronze color, and the only thing I've figured out to do, is step back with paper a bit, and repeat.
All the park or hot blued finishes I've seen just have a different color to them though, that that deep black you can get with ferric when things go perfect. I did have a manganese park kit I was planning to try, but I let someone borrow it and never got it back. However most of the parking I've seen leaves a finish I can readily identify as phosphated, which is in fact, it's original intention, and purpose, to leave a microtextured finish to hold oil.
