Personal Fab
THE ITCH TO ETCH
By Tom Owad
THERE ARE MANY WAYS TO DO INTRICATE metalwork, but most of them involve expensive machinery or high-level training. One method,
though, is accessible to all: chemical etching. This
method is very similar to that used to etch hobbyist
circuit boards: a mask is placed on the metal, and
the non-masked area is dissolved by chemicals.
Brass is well suited to the process and produces
attractive results. Shapiro Supply will sell you a
.078" thick, 8" square piece for $11. See their listings
on eBay ( myworld.ebay.com/ssshapiro).
Design your mask and print it out on a laser printer
using inkjet paper. Keep in mind that the mask covers
the areas that do not get removed. The project shown
here is a Victorian-style panel for a 20× 2 LCD. You can
find this design, and others by Andrew Lewis, in the
gallery section of monkeysailor.co.uk.
Scrub the brass clean and then wipe with isopropyl alcohol. Place your print facedown on the
brass and iron it for a minute or two, until the toner
heats and sticks to the brass. Now soak the plate
in a dish of water for 10 to 15 minutes, or until the
paper is sufficiently soft that you can remove it.
Remove the paper, then mask the back of the brass
plate by covering it with gaffer’s tape (like duct tape,
but it doesn’t leave so much residue).
Next, prepare a solution of ferric chloride (FeCl3).
It’s available as a liquid solution from E-Clec-Tech
( e-clec-tech.com) or as a solid you have to mix
yourself from United Nuclear ( unitednuclear.com).
ETCHPUNK: Brass
cover for LCD display.
WARNING: Your ferric chloride should come with
a Material Safety Data Sheet. Wear goggles, as it will
blind you if it gets in your eyes. Also wear gloves and
work in a well-ventilated area. The fumes are extremely
noxious. Anything the ferric chloride touches will be
permanently stained orange. More safety info is available
at makezine.com/go/fecl3.
If you’re looking on eBay, you’ll notice you can get
anhydrous ferric chloride quite cheap. Avoid this, as it
gets extremely hot when mixed into a solution and must
be added to the water very gradually. If you add water
directly to the anhydrous crystals, it has the potential
to flash into steam, spraying your face with boiling hot
FeCl3. And you’d have to buy more ferric chloride, eliminating the cost savings.
Dip the plate into the ferric chloride and let it sit
for 10 to 30 minutes. The time required depends on
the temperature (warmer is faster) and the depth
of etching required. When you’re satisfied with the
etch, remove the plate and rinse it in water. Wipe
clean with wire wool.
That’s it — a bit of ferric chloride and a laser
printer are really all you need. This particular project requires some drilling and cutting to finish the
LCD panel, but if you’re just doing something decorative, you’re done.
Copper can be used as easily as brass. Aluminum
can also work, but be careful, as it gets very hot and
gives off noxious fumes. Use a weaker solution.
It’s also possible to cut all the way through the
metal. Suppose you’d like to make a cog. Print out
2 copies of the cog, and iron one to each side of
the plate, lining them up. The ferric chloride will eat
around the cog’s mask on both sides, leaving a hole
where the 2 sides meet in the middle, and leaving
the shape of the cog intact.
Tom Owad is the owner of Schnitz Technology, a Macintosh
consultancy in York, Pa. He spends his days tinkering and
learning, and is the owner and webmaster of applefritter.com.
Photograph by Tom Owad
48 Make: Volume 12
