Q: Deep Etching 303 Stainless

I can't lend much to the etching process of 303, but I can assure you, having worked with aqua-regia (nitric-muriatic acid baths) for over 20 years in the precious metal refining business, that if you use any of it anywhere near your shop, you'll end up with rust on any and everything made from iron. The fumes that are liberated, even when just being stored, are horrible. Be certain you have a place to do this kind of work that is secure (safety) and isolated from your tools.

Harold

Your best option may be electrochemical etching. It's an easy and safe process, and I have had good luck with it. Beware the commercially available equipment for it, though, it is ridiculously expensive. The process, materials, and equipment are quite simple, but information is closely guarded within the industry. Bob Warner, a knifemaker, has from time to time posted some useful information about the process and equipment on various knife forums. His tutorials page (check out "Electro-Etcher" and "Stencil Exposure unit") provides a good starting point:

Some Google searches should fill in the gaps.

Good luck,

Jim

Thank you for the link, it looks like a great process. I would rather use electricity than strong acids any day.

What did you use for your resist? I am thinking of using bee's wax and asphaultum as Boye recommends, but it seems like there must be some modern improvement from 1970's tech. I saw a passing reference to floor wax tinted with food coloring.

Almost time to stop reading and start "doing."

-Galileo.

Me, too.

I've been very happy with the photo-sensitive stencils. I create the image on the computer, print it on a LaserJet to make a contact mask, and expose the film using simple light box that I made.

Jim

What is the electrolyte used?

-- Greg

For stainless, I hear that the commercial ones are best, but I don't know from experience. Last summer, I got samples of three different electrolytes from IMG, intending to experiment with them on different steels, but I haven't got round to doing that yet. The price was very reasonable -- if I recall correctly, the samples were free (I was ordering stencil material at the time). If they did charge me for the electrolyte, it was something like five bucks.

My contact was Patricia Bruno, and she was very helpful. She also mentioned something about an inexpensive "knifemaker's sample pack" with five different electrolytes that they were planning to offer.

Snoop around their web site for some good basic information on the process and equipment in general.

Anyway, I have used the SC-50 on O1 and it works very well. However, I have also had good results with a homebrew electrolyte composed of about equal parts of potassium chloride and salt in water. It works even better with a bit of muriatic acid added. I had been experimenting around with this before I got the stuff from IMG, and it worked pretty well. I got the "recipe" from a paper on sheet metal strain studies.

The original recipe in the paper was: potassium chloride, 80g sodium chloride, 90g nitric acid, 100ml hydrochloric acid, 100ml water, 4.5L

I didn't have any nitric acid, so I just winged it with what I had on hand and it worked well enough. I had previously tried various concentrations of just salt and water, with poor results.

BTW, the whole process is well within reach of the do-it-yourselfer. I made both the light box to expose the stencils and the electro-etcher for a fraction of what commercial units cost, and all from information available on the web.

Good luck!

Jim

There is also a wealth of information about electro-etching at the Custom Knife Directory forums:

Bob Warner is co-moderator of the tool forum.

When you get there, use the blue search button at the top of the screen and type in "etching" or "stencil." You'll get dozens of hits and one or two very good tutorials.

-chib