I am in the process of making several tools for use on the lathe, and
hope to sell some of them at cost, I would like to be able to etch
the shaft with a logo, as well as polishing the shaft. I have access
to a faily well equipped high school metal shop(was thinking of
mounting on one of the lathes to polish.

On 27 Feb 2004 15:35:33 -0800, (Reyd Dorakeen) wrote:

I am in the process of making several tools for use on the lathe, and
hope to sell some of them at cost, I would like to be able to etch
the shaft with a logo, as well as polishing the shaft. I have access
to a faily well equipped high school metal shop(was thinking of
mounting on one of the lathes to polish.
Hay Raid,
You know, I was thinking about Roadmarks just about an hour ago. How
it could be a good movie. Anyway, get that stuff they use for ecthing
circuit boards at radio shack. It's ferric chloride. Stains fingers
real good but will etch steel. Lacquer or wax the part and scratch
through to make your image and then submerge, agitating once in a
while, and check now and then 'till it's deep enough.
Cheers,
ERS

Reyd Dorakeen wrote...
I would like to be able to etch the shaft with a logo
...

Electrochemical etching is an easy and safe process. It can be used to
make a deep etch or a very thin surface mark. Beware of commercially
available electro-marking equipment, though; it is ridiculously
expensive. On the other hand, it is very easy and inexpensive to build
your own. My electro-etcher is shop made from materials I had on hand.
The process, materials, and equipment are almost trivial, but information
is closely guarded within the industry.

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

Knife maker Bob Warner's tutorials provide a good starting point:
http://www.warnerknives.com/tutorials.htm
(check out "Electro-Etcher" and "Stencil Exposure unit")

Additional practical information on the process can be found he
http://www.ckdforums.com/

Electrochemical etching requires an electrolyte. Last summer, I got
free 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. I did use the SC-50 electrolyte on O1 and it worked very
well.

However, I also had good results with a homebrew electrolyte of about
equal parts of potassium chloride and salt in water. This solution works
even better with a bit of muriatic acid added. I was experimenting around
with this before I got the commercial electrolytes from IMG, and it
worked pretty well. The "recipe" came 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

With no nitric acid readily available, I just winged it with what I had
on hand and it worked well enough. I had previously tried various
concentrations of plain salt and water with poor results.

On stainless steels, I have heard that the commercial electrolytes are
best, but I don't know from experience.

My contact at IMG was Patricia Bruno. 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. Here is
IMG's web page.

http://www.img-electromark.com/catalog3.php

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

The technology is solidly within reach of the average do-it-yourselfer. I
made both the light box for exposing the stencils and the electro-etcher
for a fraction of what the commercial units cost, all from information
available on the web. My total out-of-pocket equipment cost was about $8
for the high-output fluorescent light bulb in the stencil exposure unit.
Everything else was already on hand in various junk boxes.

I did buy photo-sensitive stencil material and developer. The stencil
material was $12 for one 8.5 x 11 sheet, but since the marks are small
and a stencil can be re-used for some time, one sheet goes a long way.
The developer is a concentrate and a quart cost me $20. I have no idea
what's in it -- for all I know it could be plain water (G).

Before I got the stencil material from IMG, I used a different photo-
sensitive material, called PhotoEZ High Resolution. As far as I know,
Gwen Gibson Designs is the only source for it.

http://photoezsilkscreen.com/

Five sheets were $38. This stuff works a little differently. It doesn't
require a special developer (just water) and it can be exposed in
sunlight. I don't think the screen is as fine as the IMG stencil
material. It doesn't handle fine detail as well. Also, the emulsion
appears to soak up some electrolyte in use, which can cause blotches to
appear on the mark. If you're doing deep etching and don't need fine
lines, though, this stuff does work. You just have to rub off any
blotches with an abrasive pad.

By the way, I tried using ferric chloride and was disappointed in the
results. It's messy, takes a long time, tends to undercut, and presents
a disposal problem.

Good luck!

Jim

Jim Wilson wrote...
... I create the image on the computer, print it on
the photo-resist using a LaserJet to make a contact
mask, and expose the film using simple shop-made light
box.

Damn! Seems I never proofread well enough. The above is incorrect. The
image is printed on ordinary paper, to make a contact mask for the
resist. Sorry for the confusion.

Jim