Yes it works quite well. Mix the ferric 50/50 with distilled water. You'll have to find a second container when you do this, of course.
Make sure the knife is really clean. Wipe with acetone or lacquer thinner if you have it, then wash with dish detergent using the hottest tap water you have, then wash again with a cleaner like 409, etc. Rinse and you're ready to dip.
Try a couple of minutes and see if you like that. You'll have to card off oxide buildup on the outside. I just used 4/0 steel wool under running water to scrub, or card it off, but maybe others have better ways as I don't do this often.
You can save the ferric chloride when you're finished. It'll just darken a bit in the container you use.
Don't drop it in the acid and go off and forget it.:barf: