Woodreaux,
As noted above, I believe damascus and I use different processes to blue the barrels. I use the slow rust or cold rust process with a German solution. I clean the polished barrels with acetone and after cleaning am careful to avoid touching the barrels with my skin. I apply the solution with fine steel wool (also cleaned with acetone) dipped into a small amount in the cap of the bottle. After evenly covering the barrel, pour any leftover solution out of the cap, but not back into the bottle. Then put the barrels aside to rust. The amount of time for rust to form depends on the temperature, humidity, type steel, and degree of polishing. Since you can't time it, just watch it. The first application will take a while and will be pretty light in color. After a layer of rust forms boil it in plain water to kill the rust, and card the rust off with steel wool cleaned with acetone. I learned to card the rust with a wire wheel in Germany, but I wasn't able to find one here that was fine enough to card without damaging the surface, consequently the steel wool substitute. Boil the barrels long enough to heat the steel so it will dry when removed from the tank and gently shaken. The rust will stop quickly but I usually let the barrels cook 15 minutes. If I don't have time for another cycle, I don't card them until the next day. Never let the barrels rust overnight. They will be ok overnight if boiled but will pit overnight if not boiled. I leave the bead in and if there is a weep hole, I leave it plugged. If water leaks, it will be obvious without looking closely. Rust boil and card as many cycles as necessary until you are satisfied. I polish with worn out 320 grit cloth after 180 and 220 backed with files (mostly Barret or Pilar files or old files ground to fit into close places). The solution I use will work on small areas that couldn't be polished and the color will still be even, and partial areas can be rusted and carded to even out missed areas. When you are satisfied, oil the barrels with regular oil and clean the bores. To finish, polish the barrel flats and side of the locking lugs, the extractor and rear barrel face, as well as the end of the muzzle bright, with worn 320 grit cloth.
I learned to use cleaned steel wool to apply the solution because it may remove any contaminates in the air (oil droplets) that find their way to the surface. This process leaves microscopic pits in the surface and color inside the pits, so it takes extreme wear to remove the color, also extremely fine polishing is not necessary and depending on the hardness of the steel the solution may not "bite" and the part may have to be re-polished with a coarser grit.
I don't have experience with the process damascus uses, so I can't answer to it.
Mike
Der Ami;
Willi Barthold (Von Ingenieur und Buchsenmachermeister) in his German text book on gunsmithing JAGDWAFFENKUNDE on page 144 quotes his blacking solution in 1 liter of distilled water as:
30 g Eisen (II)-sulfat FeSO4--7 H20
15 g Eisen (II)-chlorid FeCl2-- 4 H2O
12 g Kupfersulfat CuSO4--5 H2O
50 g Alkolhol (absolut)
He says that smaller amounts of the solution can be made by reducing such as 10 percent.
Barthold's blacking solution is the practically the same solution as Angiers quote on page 88 (C.17. Swiss black (Beutel. Is your German solution similar?
I have used Barthold's solution in the past with success. It was also a favorite solution of the late Jack Rowe.
Stephen Howell
