FeCl etch trouble shooting

[Bleu86]

What did I do wrong?

I'm trying to bring out my first hamon. After hand sanding it up to an 800 grit finish I submerged it in the FeCl, a total of three 10 (ish) minute soaks, with a 0000 steel wool scrub between each. After the final soak I neutralized with baking soda and then scrubbed with dish soap and water. The knife was now rough to the touch. I began sanding at 800 grit again but to get the knife to feel smooth again, I had to basically sand past all of the activity the etch brought out, while other areas just wouldn't seem to polish up at all. The hamon in particular seemed like a never ending source of oxide streaks, despite being nearly as faint as it was before etch. I finally gave up and took it back to the belt grinder to bring it back to raw steel (this thing is gonna be a fillet knife by the time I'm through). I'll start the hand sanding journey again tomorrow. 

I'm sure i did something wrong. I know I didn't get the knife as clean as I thought, there were a few blotchy spots, but those were separate from the worst areas that wouldn't polish. Was my FeCl too concentrated? Did I leave it in too long? Not long enough?  Ferric was labeled as "ready to use" in the bottle but I diluted it roughly 50/50 with water.  No pics because I didn't think to document anything until I was almost done at the grinder.

[Steve Sells]

this isnt made for knives, its made for etching PC Boards, so it saying ready to use is based on its original intended use, not our intended use, cut back on the strength and Yes it is going to be a little rough, thats a result of etching.  I use my fingers to rub clean with baking soda water after etching not steel wool

[Latticino]

Ferric, even diluted, may be far too aggressive for hamons.  Those who do a lot the subtle hamons that result from differential hardening (like the claying used for Japanese swords) polish up to very high grits (2,000+) before doing a very mild etch with diluted vinegar, then repolish.  As I understand it the hamon should start to show up from the polish alone, though this presupposes that the careful polishing standards are followed (I believe typically this is traditionally done with stones or similar).  Buffing wheels are certainly not used.

[velegski]

At 800 grit you should have seen the hamon boundaries. 

Try reducing your FeCl to 1:4 or 1:6 ratio.  Shorter soaks times.. times vary by makers. Times vary from several short 30 sec to 5 five minute soaks. Some use  vinegar as suggested by Latticno.

Generally I take the sanding to 1200 or 1500 grit. Then acid etching, then a light steel wool followed by Flitz polishing compound. I try to avoid additional sanding after etching I see it sometimes removing the hamon lines.

Lastly some steels develop hamons better than others.