Help, please: Some more Damascus Questions.

[Doc Mark]

O.K. I've been experimenting with inlaying into Damascus as I mentioned a couple of weeks ago. My new quandary is why can't I get the same reflective "color" after I inlay, polish and re-etch? Below is a photo of two pieces of Damascus. The one on the LEFT is how it came from the maker. The one on the RIGHT is after I polished it to 2000 grit and re-etched with Ferric Chloride. The entire surface is matte looking. If I try to polish it, even gently, I begin to lose the Damascus patterning. Even 4-0 steel wool won't bring back the relatively high shine of the original metal with out damaging the pattern. The photo isn't the best, as it doesn't really show how much more shiny the original metal appears. I've also tried different acids and differing amounts of time in the acid bath. All to no avail. They all look too matte and overtly dark. I have also tried to do a "gentle" polishing with rouge and the like, but can't get the "bright metal" layer to shine again.

I'm open to any and all suggestions. Maybe some of you who have done any knife making with Damascus.

(Please ignore the unfinished gold work. Much of it needs to be torn out and redone. I've cheated and have done a rather quick and dirty correction of major flaws with Photoshop.)

 

[auto45lee]

Looks like it was buffed after etching.

 

[Jan Hendrik]

You can try 2000 grit sandpaper. If the whole surface becomes shiny then your problem is you need to leave the piece in the Ferric Chloride longer to etch the layers containing less nickel deeper. This will create hills and valleys on the layers of the Damascus. You can the gently sand with 2000 grit sandpaper to give a shine to the high laying ridges of the steel.

 

[Idaho Flint]

Temperature of the acid can also effect how it bits one metal vs the other. You can try warming up the acid before you bath the piece. Be warned that the acid will bite faster at warmer temps.

 

[Ron Spokovich]

Idaho Flint is correct, in that elevated bath temperature will accelerate the etching process. When you see the 'smoke' arise from the bath, and it's warm or slightly 'hot' to the touch, go no further in temperature. As I know well from experience, wear a mask or do the process outdoors, as in breathing the fumes you'll feel you're 'under attack'. Been there, and done that. The temperature will hasten the process. USE BREATHING PROTECTION!

 

[tsterling]

Your matte finish comes from the etching revealing the microscopic structure of the metal, and the dark color comes from the oxides left by the ferric chloride (similar to gun bluing). I'm guessing the original was not only polished, but also burnished, perhaps by a wire brush or pretty coarse steel wool? Plus, it looks like the original had a pretty long etch time for that much difference in elevations.

I'm assuming you inlay the gold first and then etch? If so, then you probably can't achieve the same finish without messing up the gold work... Also, I don't really see the need to go to 2000 grit before the etch. While etching won't remove any prominent scratches (and instead may enhance them...), the etch will destroy your nice surface by revealing the microstructure of the steel. Maybe 400 or 600 grit is all you really need?

Personally, I like your version better...but then I'm not big on shiny. I'd go with Jan's suggestion of fine sandpaper on the high spots, leaving dark in the valleys.

Good luck!

Tom

 

[Doc Mark]

Thanks for all the info guys! The reason that I went up to 2000 grit was to give the gold a better polish. I'll try to warm the acid and leave it in the bath a while longer. Any suggestions as to the amount of time knifemakers use when they etch Damascus? Are we talking a few minuets or close to an hour?

 

[DanM]

A little reading material from the experts................

https://www.google.com/search?q=acid+etching+site%3A+www.bladesmith%27sforum.com&ie=utf-8&oe=utf-8

 

[Dave London]

might try a Sanford EraserStik TM to polish the gold

 

[Hot Knobs]

Dock, don't know what your piece of damascus is made of that will make a difference on the outcome of the finish, most of the blade steel I use is 1095 and 15 N 20, I go to 400 grit etch 30 mi. go to 800 etch 30 mi. and go to 1500 works for me, you get the shine on the 15 N 20 nickel. Deane

 

[jerrywh]

I think you are using too strong of an etch afterwards. As stated ,The temperature increase will accelerate the etch. When doing Damascus barrels the etch is only about 10% or less. Maybe only 5%. The idea is to only etch the softer metals. I am now working on a Damascus barrel for a rifle. There will be a lot of gold work on it. Goo real week on the acid. You can always leave it in the bath longer but a strong acid is very hard to control. Like the man said- slower is faster in this case.
Brownell sells a wire brush with .003 bristles. I use it on gold and Damascus often. It might work wonders on your piece. Run it at a slow speed in the drill press. do not run at 3450 rpm. Try about 1200 rpm or lower.

 

[Doc Mark]

Thank Hot Knobs and Jerry,

I never read about doing the etch in two sequences after different sanding grits. It sounds interesting, so I'll give it a try tonight or tomorrow.

Jerry, I'll have to check on the concentration of the acid I'm using.

Mark

 

[Hot Knobs]

Dock, I think I use 4 to 1 mix and use it cold. Deane