Beautiful flashlights! Even that older HDS there.
A combination of steps to experiment with depending on the look desired. I cannot comment on how well the piece was forged as that may also be a factor in the etch. Finishing evenly and that the piece is clean before the etch is an important part that comes in. When I get an uneven etch it usually is that I've not maintained an even finish in those areas. Getting it clean is highly important, Acetone, degreasers, etc.
I finish bolsters to an A30 and etch in a 30% ferric chloride solution. 50% is fairly aggressive depending on ambient temperatures. With the Devin Thomas mokume 1 minute at about 75F is a light etch and where I usually stop. This is just enough to feel some of the ridges between the metals. I'll neutralize then rub it with a polishing paste. The air will naturally work away to reveal the colors over time.
I've been suggested 5% vinegar in a 50-50 mix but I've not experimented with mokume to see how well vinegar actually does.
This is the bolster on my EDC finished as described above. This has been carried for the last 3 years and is the contrast that has resulted.
