Etching un-ground damascus?

L

Leon Husock

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Jul 17, 2019
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Is it possible to chemically strip/wirebrush the scale off a piece of steel to get it clean enough that you can actually etch the pattern? Or even if you did is there the issue of decarb where the damascus you have on the surface of a piece won't get a nice etch anyway? There are just some shapes and effects that are possible to get via forging but very difficult or impossible to achieve with a grinder.
 
Soak in pickle overnight. Steel pickle is a sodium bisulphate solution (Ph-Down). The normal concentration is 10% solution. one cup per gallon is good.
Then - scrub with a wire brush, wash off. You should see the pattern, but if you want you can now give it an etch.
 
Stacy E. Apelt - Bladesmith said:
Soak in pickle overnight. Steel pickle is a sodium bisulphate solution (Ph-Down). The normal concentration is 10% solution. one cup per gallon is good.
Then - scrub with a wire brush, wash off. You should see the pattern, but if you want you can now give it an etch.
Click to expand...
Awesome, thank you. This opens up a lot of possibilities!
 
White Vinegar works as well .. you can soak the piece overnight /brush /rinse it off pretty easily...
 
It is a good practice to pickle all forgings. It removes the scale and slag. It definitely makes grinding easier. If you forge a lot, pickling is just part of good shop procedures.
You can pickle as much as needed on things that get many forging procedures (damascus billets). It usually pickles enough in an hour to clean up and do the next procedure.

While vinegar works, sodium bisulfate works much better. It is what the steel is pickled in after rolling at the mill. After using pickle, most folks never return to vinegar. Pickle is also very cheap. $15-20 will buy most folks a lifetime supply. It can be used repeatedly, just like FC. Top it up with a few tablespoons of fresh powder every now and then. Easily disposed of by diluting in 5 gallons of water and pouring down the drain.

Always use good mixing practices:
Add the powder to the water slowly and stir continuously until it is dissolved.
Wear face/eye protection and stay upwind from any fumes.
Mix in a proper container. If you pickle regularly, a PVC pipe tank like is used for FC works well. 4" or 6" diameter pipe is a good size.
 
Will this work with the scale from a HT oven also? I have never worked with Damascus but a buddy gave me a small billet to use in his liner lock. I have it surfaced ground flat. After grinding my Pre-HT bevels, I plan on HT in my kiln. After heat treat I'll grind the bevels down to their final size an the edge to it's final thickness. I can't do much to the flats without tweaking my backspacer as well. I normally just hit them on the disc grinder with a fine sandpaper to shine it up. When I do this with my stock removal knives, the bevels etch much darker than the flats and I'm guessing that's because I removed more metal from the bevels Post-HT than I removed from the flats.
 
A HT oven makes decarb, not scale. While pickling will lighten the color, only grinding will remove the thin layer of decarb.

TIP:
A quick dip in the FC tank will show if the decarb is ground off. Decarb will show up as a bright gray blotch or area. The hard steel will be dark.
 
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Thanks Stacy. Guess I'll keep doing test etches until I get the flats as dark as my bevels. Hoping I don't have to take too much off and alter the backspacer dimensions too much!
 
I got 24" of 4" PVC sch 40 pipe with a couple of end caps. A gal of water fills within 6" of top. Got it clamped to fence post - I think it will work good. I left a piece soaking overnight and boy did it "etch" the metal 💪 and got the scale off also. :)

Stacy, Thanks for the info
 
If it is too strong, just dilute with more water. If the etch from an overnight soak is more than you want/need, soak for a shorter time.
 
I think the strength is good, and it soaked for much more than overnight. I put billet in early that morning and was checking during the day and it was looking good, making progress. I'd planned to remove late that afternoon...... then my CRS kicked in and I remembered it next morning.
 
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